JP2009162123A - Refrigerating cycle device and fluid machine used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the transfer of heat from a principal compressing mechanism to a motive energy recovery unit. <P>SOLUTION: A fluid machine 10A is equipped with an airtight container 11, the principal compressing mechanism 3 and the motive energy recovery unit 7. The motive energy recovery unit 7 includes a sub compressing mechanism 2 and a motive energy recovery mechanism 5. A buffer 107 is provided between the principal compressing mechanism 3 and the motive energy recovery unit 7. The buffer 107 constitutes a discharge channel of a working fluid discharged from a discharge opening 49 of the sub compressing mechanism 2 and makes a cross-sectional area of a flow path of the working fluid larger than an opening area of the discharge opening 49 of the sub compressing mechanism 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus and a fluid machine used therefor.

  In general, a refrigerant circuit includes a compressor that compresses a refrigerant, a radiator that cools the refrigerant, an expansion valve that expands the refrigerant, and an evaporator that heats the refrigerant. In the refrigeration cycle in this refrigerant circuit, the refrigerant drops in pressure from the high pressure to the low pressure in the expansion valve, and internal energy is released at that time. For this reason, when the pressure difference between the low pressure side (evaporator side) and the high pressure side (heat radiator side) of the refrigerant circuit is large, the released internal energy becomes relatively large. Therefore, the energy efficiency of the refrigeration cycle is greatly reduced.

  In view of such a problem, various techniques for recovering the internal energy of the refrigerant released during expansion have been proposed. For example, in Patent Document 1 and Non-Patent Document 1, power recovery is performed by arranging a positive displacement fluid machine composed of an expansion mechanism and a blower (sub compression mechanism) connected to each other by a shaft as a power recovery mechanism. A refrigeration cycle apparatus has been proposed.

In the refrigeration cycle apparatus described in Patent Literature 1 and Non-Patent Literature 1, as shown in FIG. 6 of Patent Literature 1, the positive displacement fluid machine and the main compression mechanism are housed in separate sealed containers. Each sealed container is provided with an oil reservoir in which the refrigerating machine oil supplied to the positive displacement fluid machine and the main compression mechanism is stored.
JP 2006-266171 A International Refrigeration and Air Conditioning Conference at Purdue, July 17-20, 2006, R169, “BASIC OPERATINGCHARACTERISTICS OF CO2 REFRIGERATION CYCLES WITH EXPANDER-COMPRESSOR UNIT”

  However, as in the refrigeration cycle apparatus described in Patent Document 1 and Non-Patent Document 1, separate oil reservoirs are provided in each of the sealed container that houses the positive displacement fluid machine and the sealed container that houses the main compression mechanism. When installed, the balance between the amount of refrigerating machine oil stored in one oil reservoir and the amount of refrigerating machine oil stored in the other oil reservoir is lost, and lubrication and sealing of the displacement fluid machine and main compression mechanism are appropriate. There is a risk that it will not be performed. This is because the amount of refrigerating machine oil discharged from the main compression mechanism to the refrigerant circuit is different from the amount of refrigerating machine oil discharged from the positive displacement fluid machine to the refrigerant circuit.

  For example, in Non-Patent Document 1, an oil separator is disposed between a main compression mechanism and a radiator, and refrigeration oil recovered by the oil separator is supplied to a sealed container in which an expansion mechanism-sub-compression mechanism unit is stored. It is described. By doing in this way, the reduction | decrease in the quantity of the refrigerating machine oil stored in the airtight container in which the expansion mechanism-subcompression mechanism unit was accommodated can be suppressed, for example.

  However, as described in Non-Patent Document 1, even when an oil separator is provided between the main compression mechanism and the radiator, the oil reservoir in the sealed container in which the expansion mechanism-sub-compression mechanism unit is accommodated. In addition, it is difficult to sufficiently suppress the decrease in the amount of refrigerating machine oil stored in the oil reservoir in the sealed container in which the main compression mechanism is housed. This is because the amount of refrigerating machine oil discharged from the expansion mechanism-sub-compression mechanism unit to the refrigerant circuit even if the refrigerating machine oil recovered by the oil separator is supplied into the sealed container in which the expansion mechanism-sub-compression mechanism unit is stored. Is more than the amount of refrigerating machine oil recovered by the oil separator, the amount of refrigerating machine oil stored in the oil reservoir in the sealed container containing the expansion mechanism-sub-compression mechanism unit is reduced. It is. In addition, when the amount of refrigerating machine oil discharged from the main compression mechanism to the refrigerant circuit is relatively large, the amount of refrigerating machine oil stored in the oil reservoir in the sealed container in which the main compression mechanism is stored decreases. is there.

  The present invention has been made in view of such a point, and an object of the present invention is to stably supply oil to the compression mechanism and the power recovery mechanism.

  As a fluid machine that can solve the above problem, the present inventors have proposed the following fluid machine in the previous application.

The fluid machine is
An airtight container in which an oil reservoir in which oil is stored is formed at the bottom;
A main compression mechanism that is disposed in an airtight container and is supplied with oil stored in an oil reservoir and compresses a working fluid;
A rotating electric motor disposed above the oil reservoir in the sealed container;
A main compressor shaft that connects the main compression mechanism and the rotary motor so that the main compression mechanism is driven by the rotary motor;
(Ii) a power recovery mechanism that recovers power from the working fluid by performing a suction stroke for sucking the working fluid and a discharge stroke for discharging the sucked working fluid; A sub-compression mechanism that is driven by the recovery mechanism and compresses the working fluid and discharges it to the main compression mechanism; and (iii) a power recovery mechanism so that the sub-compression mechanism is driven by the power recovered by the power recovery mechanism; And a power recovery unit that includes a power recovery shaft that connects the sub-compression mechanism.

  In the fluid machine, oil that lubricates the main compression mechanism and the power recovery unit is collectively stored in an oil reservoir in the hermetic container. For this reason, there is essentially no problem of excessive or insufficient oil, and oil can be stably supplied to the main compression mechanism and the power recovery unit. Since the main compression mechanism and the power recovery unit are accommodated in a common sealed container, it is advantageous for reducing the installation space.

  However, there is a new problem caused by housing the main compression mechanism and the power recovery unit in a single sealed container. Since the working fluid is compressed by the main compression mechanism to be in a high temperature and high pressure state, members constituting the main compression mechanism are relatively hot. On the other hand, since the working fluid is expanded by the power recovery mechanism of the power recovery unit to be in a low temperature and low pressure state, the members constituting the power recovery unit are relatively low in temperature. The sub-compression mechanism has an action of compressing the working fluid, but the temperature rise and pressure rise in the sub-compression mechanism are not large. Accordingly, when the main compression mechanism and the power recovery unit are accommodated in a single sealed container and lubricated with the refrigerating machine oil stored in the common oil reservoir, the power recovery unit is removed from the main compression mechanism via the refrigerating machine oil. The heat moves to. This heat transfer causes a decrease in the temperature of the working fluid discharged from the main compression mechanism and an increase in the temperature of the working fluid discharged from the power recovery mechanism, and hinders improvement in energy efficiency.

  As a result of intensive studies to suppress heat transfer from the main compression mechanism to the power recovery unit, the present inventors have completed the following invention. Specifically, in the fluid machine, a buffer is provided between the main compression mechanism and the power recovery unit. The buffer forms a suction path for guiding the working fluid to the suction port of the sub-compression mechanism or a discharge path of the working fluid discharged from the discharge port of the sub-compression mechanism, and the cross-sectional area of the flow path of the working fluid is set to the suction port It plays the role which expands rather than the opening area of this, or the opening area of a discharge outlet.

  The buffer forms a suction path for guiding the working fluid to the suction port of the sub-compression mechanism, and an upstream portion that extends the cross-sectional area of the flow path of the working fluid beyond the opening area of the suction port; It may include a downstream portion that forms a discharge path for the working fluid discharged from the discharge port and expands the cross-sectional area of the flow path of the working fluid beyond the opening area of the discharge port.

  According to the present invention, oil can be stably supplied to the compression mechanism and the power recovery unit. By providing a buffer between the main compression mechanism and the power recovery unit, heat transfer from the main compression mechanism to the power recovery unit can be suppressed. Moreover, the heat which moves toward the power recovery unit side from the main compression mechanism side can be recovered by the working fluid flowing through the buffer.

<Embodiment>
FIG. 1 is a cross-sectional view of a fluid machine 10A used in the refrigeration cycle apparatus 1A according to the present embodiment. FIG. 2 is a configuration diagram of the refrigeration cycle apparatus 1A according to the present embodiment. First, a schematic configuration of the refrigeration cycle apparatus 1A will be described with reference to FIG. Note that the refrigeration cycle apparatus 1A described here is an example of a preferred embodiment in which the present invention is implemented, and the present invention is not limited to the following configuration.

<Outline configuration of refrigeration cycle apparatus 1A>
As shown in FIG. 2, the refrigeration cycle apparatus 1 </ b> A includes a refrigerant circuit 9 having a main compression mechanism 3, a radiator 4, a power recovery mechanism 5, an evaporator 6, a sub-compression mechanism 2, and a buffer 107. I have. The refrigerant circuit 9 is filled with a refrigerant that becomes a supercritical pressure in a high-pressure side portion from the main compression mechanism 3 through the radiator 4 to the power recovery mechanism 5. Specifically, the refrigerant circuit 9 is filled with carbon dioxide. However, the present invention is not limited to this configuration. For example, the refrigerant circuit 9 may be filled with a refrigerant that does not reach the supercritical pressure on the high pressure side. Specifically, the refrigerant circuit 9 may be filled with, for example, a fluorocarbon refrigerant.

  The main compression mechanism 3 is driven by an electric motor 8 which is a kind of rotary electric motor. The main compression mechanism 3 compresses the refrigerant circulating in the refrigerant circuit 9 to high temperature and high pressure. In the present embodiment, an example in which the main compression mechanism 3 is a scroll type compression mechanism will be described. However, in the present invention, the main compression mechanism 3 is not limited to the scroll type compression mechanism. In the present invention, the main compression mechanism 3 may be, for example, a rotary type compression mechanism.

  A radiator (gas cooler) 4 is connected to the main compression mechanism 3. The radiator 4 radiates the refrigerant compressed by the main compression mechanism 3. In other words, the radiator 4 cools the refrigerant compressed by the main compression mechanism 3. The refrigerant cooled by the radiator 4 becomes low temperature and high pressure.

  The power recovery mechanism 5 is connected to the radiator 4. In the present embodiment, the power recovery mechanism 5 is constituted by a rotary fluid pressure motor. Specifically, the power recovery mechanism 5 performs a process of sucking the refrigerant from the radiator 4 and a process of discharging the sucked refrigerant substantially continuously. That is, the power recovery mechanism 5 sucks the refrigerant that has been made low temperature and high pressure by the radiator 4 and discharges it to the evaporator 6 side without substantially changing the volume. Here, due to the main compression mechanism 3, the radiator 4 side has a relatively high pressure across the power recovery mechanism 5, and the evaporator 6 side has a relatively low pressure. For this reason, the refrigerant sucked into the power recovery mechanism 5 expands to a low pressure when discharged from the power recovery mechanism 5. In the present invention, the power recovery mechanism 5 is not limited to a rotary fluid pressure motor. The power recovery mechanism 5 may be a fluid pressure motor other than the rotary type. The power recovery mechanism 5 may be, for example, an expansion mechanism having a specific volume ratio (the volume ratio is greater than 1).

  The evaporator 6 is connected to the power recovery mechanism 5. The evaporator 6 heats and evaporates the refrigerant from the power recovery mechanism 5.

  The sub-compression mechanism 2 is disposed between the evaporator 6 and the main compression mechanism 3, specifically, between the evaporator 6 and the buffer 107. The sub-compression mechanism 2 is connected to the power recovery mechanism 5 by a power recovery shaft 12. The sub compression mechanism 2 is driven by the power recovered by the power recovery mechanism 5. The sub compression mechanism 2 preliminarily boosts the refrigerant from the evaporator 6 side and then supplies the refrigerant to the main compression mechanism 3. In the present embodiment, the sub-compression mechanism 2, the power recovery mechanism 5, and the power recovery shaft 12 constitute a power recovery unit 7.

  The sub-compression mechanism 2 is not limited to the one that discharges the sucked refrigerant after it is compressed in the working chamber. For example, the sub-compression mechanism 2 may be a supercharger that substantially continuously performs a process of sucking the refrigerant from the evaporator 6 and a process of discharging the sucked refrigerant to the main compression mechanism 3 side. Good. That is, the sub compression mechanism 2 is not particularly limited as long as it can boost the pressure of the refrigerant sucked into the main compression mechanism 3. Here, an example in which the sub compression mechanism 2 is configured by a supercharger will be described.

<Specific configuration of refrigeration cycle apparatus 1A>
(Fluid machine 10A)
As shown in FIGS. 1 and 2, the fluid machine 10 </ b> A includes a substantially cylindrical airtight container 11, a main compression mechanism 3, an electric motor 8, and a power recovery unit 7. The sealed container 11 includes a cylindrical trunk shell 11a, an upper shell 11b, and a bottom shell 11c. The upper opening of the trunk shell 11a is closed by a lid-like upper shell 11b. On the other hand, the lower opening of the trunk shell 11a is closed by a bowl-shaped bottom shell 11c.

  An oil reservoir 16 in which refrigerator oil is stored is formed at the bottom of the sealed container 11. The main compression mechanism 3 and the electric motor 8 are arranged at a position higher than the oil reservoir 16 in the sealed container 11. Specifically, the main compression mechanism 3 is disposed farthest from the oil reservoir 16. The electric motor 8 is disposed at a position lower than the main compression mechanism 3. A power recovery unit 7 is disposed in the oil reservoir 16. Of the power recovery unit 7, the sub-compression mechanism 2 is disposed closer to the main compression mechanism 3. That is, the sub compression mechanism 2 is disposed at a relatively high position.

  Between the main compression mechanism 3 and the power recovery unit 7 in the axial direction of the power recovery shaft 12, a buffer component 244 having a buffer 107 is disposed. The buffer component 244 is provided in the oil reservoir 16. The buffer 107 serves as a flow path (discharge path) for the refrigerant discharged from the sub-compression mechanism 2 and expands the cross-sectional area of the flow path. The buffer constituent member 244 suppresses heat transfer from the main compression mechanism 3 to the power recovery unit 7 (particularly, the power recovery mechanism 5), and the main compression mechanism is cooled by the refrigerant flowing through the buffer 107 in the buffer constituent member 244. 3 and the exhaust heat of the electric motor 8 are collected.

(Configuration of electric motor 8 and main compression mechanism 3)
The electric motor 8 includes a cylindrical stator 8b and a columnar rotor 8a. The stator 8b is fixed to the body shell 11a of the sealed container 11 in a non-rotatable manner by shrink fitting. The rotor 8a is disposed inside the stator 8b. The rotor 8a is rotatable with respect to the stator 8b. A through hole penetrating in the axial direction is formed in the center of the rotor 8a in plan view. A main compressor shaft 38 extending vertically from the rotor 8a is inserted and fixed in the through hole. The main compressor shaft 38 rotates when the electric motor 8 is driven.

  The lower end portion of the main compressor shaft 38 is rotatably inserted into a substantially disc-shaped sub-bearing member 71 fixed to the body shell 11a. The auxiliary bearing member 71 is disposed in the oil reservoir 16. The auxiliary bearing member 71 is formed with one or a plurality of openings 71 a so that the refrigerating machine oil stored in the oil reservoir 16 can flow up and down the auxiliary bearing member 71. The auxiliary bearing member 71 also functions as an oil level stabilizer for stabilizing the oil level.

  An oil pump 72 as an oil supply unit is disposed at the lower end of the main compressor shaft 38. The refrigeration oil stored in the oil reservoir 16 is sucked up by the oil pump 72, and the refrigeration oil is supplied to the main compression mechanism 3 through an oil supply hole (not shown) formed in the main compressor shaft 38. Supplied. Thereby, the main compression mechanism 3 is lubricated and sealed. The refrigerating machine oil supplied to the main compression mechanism 3 passes through a gap between the rotor 8a and the stator 8b and returns to the oil reservoir 16 again.

  As shown in FIG. 1, the main compression mechanism 3 is a scroll type compression mechanism. The main compression mechanism 3 is fixed to the trunk shell 11 a of the sealed container 11. The main compression mechanism 3 includes a fixed scroll 32, an orbiting scroll 33, an Oldham ring 34, a bearing member 35, and a muffler 36.

  The fixed scroll 32 is attached to the trunk shell 11a of the sealed container 11 so that it cannot be displaced. On the lower surface of the fixed scroll 32, a spiral wrap 32a (for example, an involute shape) is formed. The orbiting scroll 33 is disposed to face the fixed scroll 32. In the center of the surface of the orbiting scroll 33 facing the fixed scroll 32, a wrap 33a having a spiral shape (for example, an involute shape) meshing with the wrap 32a is formed. A crescent-shaped working chamber (compression chamber) 39 is defined between the wrap 32a and the wrap 33a. The fixed scroll 32 has an opening 32 d that opens into the working chamber 39. A suction pipe 32c is attached to the opening 32d. The suction pipe 32c is connected to the discharge pipe 51 by a communication pipe 70 as shown in FIG. The refrigerant is supplied to the working chamber 39 through the communication pipe 70 and the suction pipe 32c.

  The peripheral portion of the facing surface of the orbiting scroll 33 is supported by being in contact with a thrust bearing 32b provided to protrude from the lower surface peripheral portion of the fixed scroll 32.

  An eccentric portion 38a having a central axis different from that of the main compressor shaft 38 is fitted and inserted into the center portion of the lower surface of the orbiting scroll 33 and provided at the upper end portion of the main compressor shaft 38 extending from the rotor 8a. It is fixed. An Oldham ring 34 is disposed below the orbiting scroll 33. This Oldham ring 34 regulates the rotation of the orbiting scroll 33. Due to the function of the Oldham ring 34, the orbiting scroll 33 orbits in a state of being eccentric from the central axis of the main compressor shaft 38 as the main compressor shaft 38 rotates.

  With the turning motion of the turning scroll 33, the working chamber 39 formed between the wrap 32a and the wrap 33a moves from the outside to the inside. Along with this movement, the volume of the working chamber 39 is reduced. Thereby, the refrigerant sucked into the working chamber 39 from the suction pipe 32c is compressed. The compressed refrigerant passes through a discharge hole 40 formed in the fixed scroll 32 and the bearing member 35 through a discharge hole 32e formed in the center of the fixed scroll 32 and an internal space 36a of the muffler 36. It is discharged into the internal space 11e of the sealed container 11. The discharged refrigerant temporarily stays in the internal space 11e. Refrigerating machine oil or the like mixed in the refrigerant during the residence period is separated by gravity or centrifugal force. And the refrigerant | coolant from which refrigeration oil etc. were isolate | separated is discharged to the refrigerant circuit 9 from the discharge pipe 11d attached to the upper shell 11b of the airtight container 11. FIG.

(Power recovery unit 7)
As shown in FIGS. 1 and 2, the power recovery unit 7 is disposed in the oil reservoir 16. The power recovery unit 7 includes a power recovery mechanism 5 disposed relatively below and a sub-compression mechanism 2 disposed relatively above. The power recovery mechanism 5 and the sub-compression mechanism 2 are integrally disposed via the power recovery shaft 12 and the first closing member 15. The power recovery unit 7 is fixed to the trunk shell 11 a in a third closing member 14 that is a constituent member of the sub compression mechanism 2.

-Configuration of power recovery mechanism 5-
As shown in FIG. 1, the power recovery mechanism 5 includes a first closing member 15 and a second closing member 13. The first closing member 15 and the second closing member 13 are opposed to each other. A first cylinder 22 is disposed between the first closing member 15 and the second closing member 13. The first cylinder 22 has a substantially cylindrical internal space. The internal space of the first cylinder 22 is closed by the first closing member 15 and the second closing member 13.

  The power recovery shaft 12 passes through the first cylinder 22 in the axial direction of the first cylinder 22. The power recovery shaft 12 is disposed on the central axis of the first cylinder 22. The power recovery shaft 12 is supported by the second closing member 13 and a third closing member 14 described later. The power recovery shaft 12 is formed with an oil supply hole 12a (see FIGS. 3 and 4) penetrating the power recovery shaft 12 in the axial direction. The refrigerating machine oil in the sealed container 11 is supplied to the bearings and gaps of the sub-compression mechanism 2 and the power recovery mechanism 5 through the oil supply hole 12a.

  The first piston 21 is disposed in a substantially cylindrical internal space defined by the inner peripheral surface of the first cylinder 22, the first closing member 15, and the second closing member 13. The first piston 21 is fitted into the power recovery shaft 12 in an eccentric state with respect to the central axis of the power recovery shaft 12. Specifically, the power recovery shaft 12 includes an eccentric portion 12 b having a central axis different from the central axis of the power recovery shaft 12. A cylindrical first piston 21 is fitted in the eccentric portion 12b. For this reason, the first piston 21 is eccentric with respect to the central axis of the first cylinder 22. Accordingly, the first piston 21 performs an eccentric rotational movement with the rotation of the power recovery shaft 12.

  A first working chamber 23 is defined in the first cylinder 22 by the first piston 21, the inner peripheral surface of the first cylinder 22, the first closing member 15, and the second closing member 13 (also in FIG. 3). reference).

  As shown in FIG. 3, a linear groove 22 a that opens to the first working chamber 23 is formed in the first cylinder 22. A plate-like first partition member 24 is slidably inserted into the linear groove 22a. A biasing means 25 is disposed between the first partition member 24 and the bottom of the linear groove 22a. By this biasing means 25, the first partition member 24 is pressed against the outer peripheral surface of the first piston 21. Thereby, the first working chamber 23 is partitioned into two spaces. Specifically, the first working chamber 23 is divided into a high-pressure side suction working chamber 23a and a low-pressure side discharge working chamber 23b.

  The urging means 25 can be constituted by a spring, for example. Specifically, the biasing means 25 may be a compression coil spring.

  Further, the biasing means 25 may be a so-called gas spring or the like. That is, when the first partition member 24 slides in the direction of reducing the volume of the back space 65 of the first partition member 24, the pressure in the space between the first partition member 24 and the bottom of the linear groove 22a. However, the pressure in the direction of the first piston 21 may act on the first partition member 24 due to the pressure difference. . Specifically, for example, when the back space 65 of the first partition member 24 is a sealed space, a reaction force is applied to the first partition member 24 when the volume of the back space 65 is reduced by the first partition member 24. Also good. Of course, the biasing means 25 may be constituted by a plurality of types of springs such as a compression coil spring and a gas spring. The pressure in the first working chamber 23 is the average pressure of the pressure in the suction working chamber 23a and the pressure in the discharge working chamber 23b.

  As shown in FIG. 3, a suction path 27 is opened in a portion adjacent to the first partition member 24 of the suction working chamber 23a. As shown in FIG. 1, the suction path 27 is formed in the second closing member 13 located below the first cylinder 22. The suction path 27 communicates with the suction pipe 28. The high-pressure refrigerant from the radiator 4 shown in FIG. 2 is guided to the suction working chamber 23 a through the suction pipe 28 and the suction path 27.

  An opening (suction port) 26 with respect to the suction working chamber 23a of the suction path 27 is formed in a substantially fan shape extending in an arc shape in a direction in which the suction working chamber 23a extends from a portion adjacent to the first partition member 24 of the suction working chamber 23a. Yes. The suction port 26 is completely closed by the first piston 21 only when the first piston 21 is located at the top dead center. At least a part of the suction port 26 is exposed to the suction working chamber 23a over the entire period except for the moment when the first piston 21 is located at the top dead center. Specifically, in plan view, the outer side edge 26a of the suction port 26 is formed in an arc shape along the outer peripheral surface of the first piston 21 located at the top dead center. In other words, the outer end side 26 a is formed in an arc shape having substantially the same radius as the outer peripheral surface of the first piston 21.

  On the other hand, a discharge path 30 is opened in a portion adjacent to the first partition member 24 of the discharge working chamber 23b. As shown in FIG. 1, the discharge path 30 is also formed in the second closing member 13 in the same manner as the suction path 27. The discharge path 30 communicates with the discharge pipe 31. Thereby, the refrigerant in the discharge working chamber 23 b is discharged to the evaporator 6 side through the discharge path 30 and the discharge pipe 31.

  An opening (discharge port) 29 of the discharge passage 30 with respect to the discharge working chamber 23b is formed in a substantially fan shape that extends in an arc shape in a direction in which the discharge working chamber 23b extends from a portion adjacent to the first partition member 24 of the discharge working chamber 23b. Yes. The discharge port 29 is completely closed by the first piston 21 only when the first piston 21 is located at the top dead center. In addition, at least a part of the discharge port 29 is exposed to the discharge working chamber 23b over the entire period except for the moment when the first piston 21 is located at the top dead center. Specifically, in plan view, the outer end side 29a of the discharge port 29 located on the radially outer side of the first cylinder 22 is formed in an arc shape along the outer peripheral surface of the first piston 21 located at the top dead center. Has been. In other words, the outer end side 29 a is formed in an arc shape having substantially the same radius as the outer peripheral surface of the first piston 21.

  When the first piston 21 is located at the top dead center, as shown in FIG. 5A, the center axis (eccentric axis) of the first piston 21 is located closest to the first partition member 24. Say. The “moment when the first piston 21 is located at the top dead center” is not strictly limited to the moment when the first piston 21 is located at the top dead center. It may have a certain period with respect to when it is located at a point. That is, when the rotation angle (θ) of the first piston 21 when the first piston 21 is located at the top dead center is 0 °, for example, the rotation angle (θ) of the first piston 21 is 0 ° ± 5. A configuration in which both the suction port 26 and the discharge port 29 are closed over a period of within (or within 0 ° ± 3 °) is also included in the configuration in which the refrigerant does not blow from the suction path 27 to the discharge path 30. To do.

  By forming the suction path 27 and the discharge path 30 as described above, as shown in FIG. 5 (a), the suction port 26 and the discharge port 29 are only at the moment when the first piston 21 is located at the top dead center. Both are completely closed. That is, both the suction port 26 and the discharge port 29 are completely closed at the moment when the first working chamber 23 becomes one. More specifically, the suction working chamber 23 a communicates with the suction passage 27 until the moment when the suction working chamber 23 a communicates with the discharge passage 30. The suction port 26 is closed by the first piston 21 after the moment when the suction working chamber 23a communicates with the discharge path 30 and the suction working chamber 23a becomes the discharge working chamber 23b. For this reason, the blow-through of the refrigerant from the suction path 27 to the discharge path 30 is suppressed. Therefore, highly efficient power recovery is realized.

  Note that, from the viewpoint of completely restricting the flow of refrigerant from the suction path 27 to the discharge path 30, both the suction port 26 and the discharge port 29 are closed at the moment when the first piston 21 is located at the top dead center. It is preferable. However, even when only one of the suction port 26 and the discharge port 29 is closed at the moment when the first piston 21 is located at the top dead center, the timing at which the suction port 26 is closed and the discharge port 29 If the difference from the timing at which the valve is closed is smaller than about 10 ° in terms of the rotation angle of the power recovery shaft 12, substantially no blow-through occurs between the suction path 27 and the discharge path 30. That is, the difference between the timing at which the suction port 26 is closed and the timing at which the discharge port 29 is closed is set to be smaller than about 10 ° as the rotation angle of the power recovery shaft 12, so The blow-through of the refrigerant to 30 can be suppressed.

  As described above, the suction working chamber 23a is always in communication with the suction path 27. Further, the discharge working chamber 23 b is always in communication with the discharge path 30. In other words, in the power recovery mechanism 5, the process of sucking the refrigerant and the process of discharging the sucked refrigerant are performed substantially continuously. The power recovery mechanism 5 does not have a specific volume ratio, and the ratio of the suction volume and the discharge volume is 1. For this reason, the sucked refrigerant passes through the power recovery mechanism 5 without substantially changing its volume.

-Operation of the power recovery mechanism 5-
Next, the operation principle of the power recovery mechanism 5 will be described in detail with reference to FIG. FIG. 5A is a view when the rotation angle (θ) of the first piston 21 is 0 °, 360 °, and 720 °. FIG. 5B is a view when the rotation angle (θ) of the first piston 21 is 90 ° and 450 °. FIG. 5C is a view when the rotation angle (θ) of the first piston 21 is 180 °, 540 °. FIG. 5D is a view when the rotation angle (θ) of the first piston 21 is 270 ° and 630 °. The rotation angle (θ) is obtained when the counterclockwise direction in FIG. 5 is positive.

  As shown in FIG. 5A, when the first piston 21 is located at the top dead center (θ = 0 °), both the suction port 26 and the discharge port 29 are closed by the first piston 21. For this reason, the first working chamber 23 is in an isolated state where it does not communicate with either the suction path 27 or the discharge path 30.

  When the first piston 21 rotates from this state, a suction working chamber 23 a communicating with the suction path 27 via the suction port 26 is formed. Here, the suction working chamber 23 a is connected to the high pressure side of the refrigerant circuit 9. Therefore, when the suction port 26 is opened, the volume of the suction working chamber 23a is increased by the high-pressure refrigerant flowing from the suction port 26 as shown in FIGS. 5 (b) to 5 (d). The rotational torque applied to the first piston 21 as the volume of the suction working chamber 23a is increased becomes a part of the rotational driving force of the power recovery shaft 12. This refrigerant suction process is performed until the rotation angle (θ) reaches 360 °, that is, until the first piston 21 is positioned at the top dead center again. That is, the suction stroke of the refrigerant is performed until just before the suction working chamber 23 a communicates with the discharge path 30.

  As shown in FIG. 5A, at the moment when the first piston 21 is again at the top dead center, in the present embodiment, both the suction port 26 and the discharge port 29 are closed by the first piston 21. As a result, the first working chamber 23 is isolated again.

  From this state, when the first piston 21 rotates, the isolated first working chamber 23 communicates with the discharge path 30 through the discharge port 29 to become the discharge working chamber 23b. Here, with the power recovery mechanism 5 as a boundary, the evaporator 6 side is at a lower pressure than the radiator 4 side due to the action of the main compression mechanism 3. For this reason, at the moment when the isolated first working chamber 23 communicates with the discharge path 30 via the discharge port 29 to become the discharge working chamber 23b, the low-temperature and high-pressure refrigerant in the discharge working chamber 23b is sucked to the low-pressure side. The Therefore, the refrigerant in the first working chamber 23 expands. The pressure in the discharge working chamber 23b is equal to the pressure on the low pressure side of the refrigerant circuit 9. The rotational torque applied to the first piston 21 by this refrigerant discharge stroke also becomes part of the rotational driving force of the power recovery shaft 12. That is, the power recovery shaft 12 rotates due to the flow of high-pressure refrigerant into the suction working chamber 23a and the suction of the refrigerant in the discharge stroke. The rotational torque of the power recovery shaft 12 is used as power for the sub-compression mechanism 2 as will be described in detail later.

  Further, as the rotation angle (θ) of the first piston 21 increases, the refrigerant in the discharge working chamber 23b is sequentially discharged to the low pressure side of the refrigerant circuit 9. Then, as shown in FIG. 5A, when the first piston 21 is again at the top dead center (θ = 720 °), the discharge working chamber 23b disappears. In synchronization with the discharge stroke, the suction working chamber 23a is formed again, and the next suction stroke is performed. As described above, a series of strokes from the start of the suction stroke to the end of the discharge stroke is completed when the first piston 21 rotates 720 °.

-Configuration of sub-compression mechanism 2-
The sub-compression mechanism 2 is connected to the power recovery mechanism 5 by a power recovery shaft 12. In other words, the power recovery shaft 12 of the power recovery mechanism 5 also serves as the shaft of the sub compression mechanism 2. In other words, the shaft of the power recovery mechanism 5 and the shaft of the sub compression mechanism 2 are integrally connected.

  The basic configuration of the sub-compression mechanism 2 is substantially the same as the power recovery mechanism 5 described above. Specifically, the sub-compression mechanism 2 includes a first closing member 15 and a third closing member 14 as shown in FIG. The first closing member 15 is a common component member of the sub compression mechanism 2 and the power recovery mechanism 5. The first closing member 15 and the third closing member 14 face each other. Specifically, the third closing member 14 faces the surface of the first closing member 15 opposite to the surface facing the second closing member 13. A second cylinder 42 is disposed between the first closing member 15 and the third closing member 14. The second cylinder 42 has a substantially cylindrical internal space. The internal space of the second cylinder 42 is closed by the first closing member 15 and the third closing member 14.

  The power recovery shaft 12 passes through the second cylinder 42 in the axial direction of the second cylinder 42. The power recovery shaft 12 is disposed on the central axis of the second cylinder 42. The second piston 41 is disposed in a substantially cylindrical internal space defined by the inner peripheral surface of the second cylinder 42, the first closing member 15, and the third closing member 14. The second piston 41 is fitted into the power recovery shaft 12 in an eccentric state with respect to the central axis of the power recovery shaft 12. Specifically, the power recovery shaft 12 includes an eccentric portion 12 c having a central axis different from the central axis of the power recovery shaft 12. A cylindrical second piston 41 is fitted in the eccentric portion 12c. For this reason, the second piston 41 is eccentric with respect to the central axis of the second cylinder 42. Accordingly, the second piston 41 rotates eccentrically with the rotation of the power recovery shaft 12.

  The eccentric portion 12c to which the second piston 41 is attached is eccentric in the same direction as the eccentric portion 12b to which the first piston 21 is attached. For this reason, in this embodiment, the eccentric direction of the first piston 21 with respect to the central axis of the first cylinder 22 and the eccentric direction of the second piston 41 with respect to the central axis of the second cylinder 42 are substantially the same.

  A second working chamber 43 is defined in the second cylinder 42 by the second piston 41, the inner peripheral surface of the second cylinder 42, the first closing member 15, and the third closing member 14 (also in FIG. 4). reference).

  As shown in FIG. 4, a linear groove 42 a that opens to the second working chamber 43 is formed in the second cylinder 42. A plate-like second partition member 44 is slidably inserted into the linear groove 42a. A biasing means 45 is disposed between the second partition member 44 and the bottom of the linear groove 42a. The second partition member 44 is pressed against the outer peripheral surface of the second piston 41 by the urging means 45. Thereby, the second working chamber 43 is partitioned into two spaces. Specifically, the second working chamber 43 is partitioned into a low-pressure side suction working chamber 43a and a high-pressure side discharge working chamber 43b.

  The urging means 45 can be constituted by a spring, for example. Specifically, the biasing means 45 may be a compression coil spring.

  Further, the biasing means 45 may be a so-called gas spring or the like. That is, when the second partition member 44 is slid in the direction of reducing the volume of the back space 55, the pressure in the back space 55 is set to be higher than the pressure in the second working chamber 43. A pressing force in the direction of the second piston 41 may act on the second partition member 44 due to a pressure difference between the back space 55 and the second working chamber 43. Specifically, for example, the back space 55 may be a sealed space, and the reaction force may be applied to the second partition member 44 when the volume of the back space 55 is reduced by the second partition member 44. Further, when the second partition member 44 is located closest to the second piston 41, the back space 55 is not a sealed space, but when the second partition member 44 is separated from the second piston 41 to some extent, the back space 55 is a sealed space. You may make it become. Of course, the biasing means 45 may be constituted by a plurality of types of springs such as a compression coil spring and a gas spring. The pressure in the second working chamber 43 is the average pressure of the pressure in the suction working chamber 43a and the pressure in the discharge working chamber 43b.

  As shown in FIG. 4, a suction path 47 is opened in a portion adjacent to the second partition member 44 of the suction working chamber 43a. As shown in FIG. 1, the suction path 47 is formed in the third closing member 14 located above the second cylinder 42. The suction path 47 communicates with the suction pipe 48. The refrigerant from the evaporator 6 (see FIG. 2) is guided to the suction working chamber 43a through the suction pipe 48 and the suction path 47.

  As shown in FIG. 4, the opening (suction port) 46 of the suction passage 47 with respect to the suction working chamber 43a is formed in an arc shape in a direction in which the suction working chamber 43a extends from a portion adjacent to the second partition member 44 of the suction working chamber 43a. It is formed in a substantially fan shape that extends. The suction port 46 is completely closed by the second piston 41 only when the second piston 41 is located at the top dead center. Then, at least a part of the suction port 46 is exposed to the suction working chamber 43a over the entire period except for the moment when the second piston 41 is located at the top dead center. Specifically, in plan view, the outer end side 46a of the suction port 46 located on the radially outer side of the second cylinder 42 is formed in an arc shape along the outer peripheral surface of the second piston 41 located at the top dead center. Has been. In other words, the outer end side 46 a is formed in an arc shape having substantially the same radius as the outer peripheral surface of the second piston 41.

  On the other hand, a discharge path 50 is opened in a portion adjacent to the second partition member 44 of the discharge working chamber 43b. As shown in FIG. 1, the discharge path 50 is also formed in the third closing member 14 in the same manner as the suction path 47. The discharge path 50 communicates with the discharge pipe 51. Thereby, the refrigerant in the discharge working chamber 43b is discharged to the buffer 107 via the discharge path 50 (see FIGS. 1 and 2). The refrigerant discharged to the buffer 107 is supplied to the main compression mechanism 3 through the communication pipe 70 and the suction pipe 32c.

  An opening (discharge port) 49 of the discharge path 50 with respect to the discharge working chamber 43b is formed in a substantially fan shape extending in an arc shape in a direction in which the discharge working chamber 43b extends from a portion adjacent to the second partition member 44 of the discharge working chamber 43b. Yes. The discharge port 49 is completely closed by the second piston 41 only when the second piston 41 is located at the top dead center. Then, at least a part of the discharge port 49 is exposed to the discharge working chamber 43b over the entire period except for the moment when the second piston 41 is located at the top dead center. Specifically, in plan view, the outer end side 49a of the discharge port 49 located on the radially outer side of the second cylinder 42 is formed in an arc shape along the outer peripheral surface of the second piston 41 located at the top dead center. Has been. In other words, the outer end side 49 a is formed in an arc shape having substantially the same radius as the outer peripheral surface of the second piston 41.

  When the second piston 41 is located at the top dead center, as shown in FIG. 6A, the center axis (eccentric axis) of the second piston 41 is located closest to the second partition member 44. Say. The “moment when the second piston 41 is located at the top dead center” is not strictly limited to the moment when the second piston 41 is located at the top dead center. It may have a certain period with respect to when it is located at a point. That is, when the rotation angle (θ) of the second piston 41 when the second piston 41 is located at the top dead center is 0 °, for example, the rotation angle (θ) of the second piston 41 is 0 ° ± 5. A configuration in which both the suction port 46 and the discharge port 49 are closed over a period of within (or within 0 ° ± 3 °) is also included in the configuration in which the refrigerant does not blow from the suction path 47 to the discharge path 50. And

  By forming the suction path 47 and the discharge path 50 as described above, as shown in FIG. 6A, the suction port 46 and the discharge port 49 are only at the moment when the second piston 41 is located at the top dead center. Both are completely closed. That is, at the moment when the second working chamber 43 becomes one, both the suction port 46 and the discharge port 49 are completely closed. More specifically, the suction working chamber 43 a communicates with the suction passage 47 until the moment when the suction working chamber 43 a communicates with the discharge passage 50. The suction port 46 is closed by the second piston 41 after the moment when the suction working chamber 43a communicates with the discharge path 50 and the suction working chamber 43a becomes the discharge working chamber 43b. For this reason, the reverse flow of the refrigerant from the discharge path 50 having a relatively high pressure to the suction path 47 having a relatively low pressure is suppressed. Therefore, highly efficient supercharging is realized. As a result, the utilization efficiency of the recovered power is improved.

  Note that, from the viewpoint of completely regulating the reverse flow of the refrigerant from the discharge path 50 to the suction path 47, both the suction path 47 and the discharge path 50 are closed at the moment when the second piston 41 is located at the top dead center. It is preferable. However, even when only one of the suction port 46 and the discharge port 49 is closed at the moment when the second piston 41 is located at the top dead center, the timing at which the suction port 46 is closed and the discharge port 49 If the difference from the timing at which the engine is closed is smaller than about 10 ° in terms of the rotation angle of the power recovery shaft 12, the reverse flow of the refrigerant from the discharge path 50 to the suction path 47 does not substantially occur. That is, the difference between the timing at which the suction port 46 is closed and the timing at which the discharge port 49 is closed is set to be smaller than about 10 ° as the rotation angle of the power recovery shaft 12, so The reverse flow of the refrigerant to 47 can be suppressed.

  As described above, the suction working chamber 43a is always in communication with the suction path 47. Further, the discharge working chamber 43b is always in communication with the discharge path 50. In other words, in the sub compression mechanism 2, the process of sucking the refrigerant and the process of discharging the sucked refrigerant are performed substantially continuously. The sub-compression mechanism 2 does not have a specific volume ratio, and the ratio of the suction volume and the discharge volume is 1. For this reason, the sucked refrigerant passes through the sub-compression mechanism 2 without substantially changing the volume.

-Operation of sub-compression mechanism 2-
Next, the operating principle of the sub-compression mechanism 2 will be described in detail with reference to FIG. FIG. 6A is a view when the rotation angle (θ) of the second piston 41 is 0 °, 360 °, and 720 °. FIG. 6B is a view when the rotation angle (θ) of the second piston 41 is 90 ° and 450 °. FIG. 6C is a view when the rotation angle (θ) of the second piston 41 is 180 °, 540 °. FIG. 6D is a view when the rotation angle (θ) of the second piston 41 is 270 ° and 630 °. The rotation angle (θ) is obtained when the counterclockwise direction in FIG. 6 is positive.

  As described above, the power recovery shaft 12 is rotated by the power recovered by the power recovery mechanism 5. Along with the rotation of the power recovery shaft 12, the second piston 41 also rotates, and the sub-compression mechanism 2 is driven.

  As shown in FIG. 6A, when the second piston 41 is located at the top dead center (θ = 0 °), both the suction port 46 and the discharge port 49 are closed by the second piston 41. For this reason, the second working chamber 43 does not communicate with either the suction path 47 or the discharge path 50 (see FIG. 4), and the second working chamber 43 is in an isolated state.

  When the second piston 41 rotates from this state, a suction working chamber 43 a communicating with the suction path 47 through the suction port 46 is formed. As the rotation angle (θ) increases until the rotation angle (θ) of the second piston 41 reaches 360 °, the suction working chamber 43a expands. When the rotation angle (θ) reaches 360 °, the refrigerant suction process ends.

  The suction working chamber 43a is always in communication with the suction path 47 until the rotation angle (θ) reaches 360 °. When the rotation angle (θ) reaches 360 °, the suction path 47 is closed by the second piston 41. When the rotation angle (θ) is 360 °, the discharge path 50 is also closed. That is, the second working chamber 43 is isolated and isolated from both the suction path 47 and the discharge path 50. When the rotation angle (θ) rotates beyond 360 °, the second working chamber 43 communicates with the discharge path 50 through the discharge port 49 and becomes the discharge working chamber 43b. When the rotation angle (θ) of the second piston 41 further increases from 360 °, the capacity of the discharge working chamber 43b decreases. At the same time, the refrigerant is discharged from the discharge working chamber 43b to the main compression mechanism 3 side. Then, as shown in FIG. 6A, when the second piston 41 is again at the top dead center (θ = 720 °), the discharge working chamber 43b disappears. The discharge working chamber 43b is always in communication with the discharge path 50 throughout the discharge stroke. Then, in synchronization with this discharge stroke, the suction working chamber 43a is formed again, and the next suction stroke is performed. As described above, a series of strokes from the start of the suction stroke to the end of the discharge stroke is completed when the second piston 41 rotates 720 °.

  As described above, the capacity of the second working chamber 43 is substantially unchanged. In addition, the suction working chamber 43 a is always in communication with the suction path 47. The discharge working chamber 43b is always in communication with the discharge path 50. For this reason, the refrigerant is neither compressed nor expanded in the second working chamber 43 of the sub-compression mechanism 2. Since the power recovery shaft 12 is rotated by the power recovery mechanism 5 and the sub compression mechanism 2 is driven, the pressure on the downstream side of the second working chamber 43 is higher than that on the upstream side of the second working chamber 43. In other words, the pressure on the main compression mechanism 3 side from the discharge port 49 becomes higher than the pressure on the evaporator 6 side from the suction port 46 by the sub compression mechanism 2 driven by the power recovered by the power recovery mechanism 5. That is, the pressure is increased by the sub compression mechanism 2.

  In the present embodiment, the timing at which the first piston 21 of the power recovery mechanism 5 is located at the top dead center and the timing at which the second piston 41 of the sub compression mechanism 2 is located at the top dead center are substantially the same. It has become.

(Buffer component 244)
The buffer constituent member 244 is provided adjacent to the power recovery unit 7. The buffer component member 244 partitions the oil reservoir 16 into a first oil reservoir 16a located on the main compression mechanism 3 side and a second oil reservoir 16b located on the power recovery unit 7 side. The periphery of the oil pump 72 for supplying the refrigeration oil to the main compression mechanism 3 is filled with the refrigeration oil stored in the first oil reservoir 16a. The periphery of the power recovery unit 7 is filled with refrigerating machine oil stored in the second oil reservoir 16b.

  The buffer constituent member 244 includes an upper buffer member 243 that forms the bottom surface of the first oil reservoir 16a, and a lower buffer member 242 that is in contact with the third closing member 14 of the power recovery unit 7. The upper buffer member 243 and the lower buffer member 242 each have an outer diameter that matches the inner diameter of the sealed container 11. The upper buffer member 243 is configured by a disk-shaped member. The lower buffer member 242 is configured by a bowl-shaped member having a disk-shaped bottom portion and a side portion rising from the outer peripheral portion of the bottom portion. By these combinations, a flat cylindrical buffer 107 is formed. When the outer diameter of the buffer constituent member 244 and the inner diameter of the sealed container 11 coincide with each other and the buffer constituent member 244 and the sealed container 11 are in direct contact with each other, the thermal resistance between them can be reduced. Therefore, the amount of heat transfer from the sealed container 11 to the buffer component 244 can be increased. In other words, heat that travels along the sealed container 11 from the main compression mechanism 3 side toward the power recovery unit 7 side can be guided to the buffer component 244.

  The buffer constituent member 244 may be fixed to the sealed container 11 or may not be fixed. Further, struts for increasing the strength of the buffer constituent member 244 may be provided in the buffer 107. Moreover, the combination of the members which comprise the buffer structural member 244 is not specifically limited. For example, the third closing member 14 of the power recovery unit 7 and / or a part of the sealed container 11 may be shared by the buffer component 244. The same applies to other embodiments described later.

  A through hole 242h that relays between the discharge path 50 of the sub-compression mechanism 2 and the buffer 107 is formed at the bottom of the buffer component 244 (the bottom of the lower buffer member 242). The refrigerant pre-compressed in the sub compression mechanism 2 is guided to the buffer 107 through the through hole 242h. The discharge path 50 of the sub-compression mechanism 2 extends inside the third closing member 14 toward the outside in the radial direction, and is connected to the through hole 242 h at the outer peripheral portion of the third closing member 14. A discharge pipe 51 penetrating the sealed container 11 is directly inserted and fixed to a side portion of the buffer constituting member 244 (side portion of the lower buffer member 242). With such a structure, an increase in the number of parts due to the provision of the buffer constituent member 244 can be suppressed as much as possible.

  It is preferable that the position of the discharge pipe 51 and the position of the through hole 242h be as far as possible from the viewpoint of increasing the refrigerant flow distance in the buffer 107. In the present embodiment, the position of the discharge pipe 51 and the position of the through hole 242h are opposite to each other by 180 ° across the axis of the power recovery shaft 12.

  The buffer 107 which is the internal space of the buffer constituent member 244 has a role of expanding the refrigerant flow path. Specifically, the cross-sectional area of the buffer 107 orthogonal to the refrigerant flow direction is larger than the opening area of the discharge port 49 of the sub compression mechanism 2. In other words, the flow path area of the buffer 107 is larger than the flow path area of the discharge path 50 of the sub compression mechanism 2. Further, the height of the buffer 107 in the axial direction of the power recovery shaft 12 is larger than the outer diameter of the discharge pipe 51. Therefore, the flow path area of the buffer 107 is wider than the cross-sectional area of the discharge pipe 51. By providing the buffer 107 having a large flow path area, the heat moving from the main compression mechanism 3 side toward the power recovery unit 5 side can be efficiently recovered by the refrigerant flowing through the buffer 107. In addition, an excellent heat insulating effect can be obtained between the main compression mechanism 3 and the power recovery unit 7.

  The buffer component 244 restricts the refrigerating machine oil between the first oil reservoir 16a and the second oil reservoir 16b. On the other hand, a communication passage 235 that allows the refrigerating machine oil to pass between the first oil reservoir 16a and the second oil reservoir 16b is provided. The communication passage 235 automatically adjusts the amount of oil between the first oil reservoir 16a and the second oil reservoir 16b.

  In the present embodiment, the communication passage 235 is constituted by an oil equalizing pipe 235 that passes through the buffer constituent member 244 in the axial direction of the power recovery shaft 12. The oil equalizing pipe 235 as the communication passage is firmly fixed to the buffer component 244 so that the refrigeration oil does not leak into the buffer 107. The oil leveling pipe 235 allows the refrigerating machine oil to flow smoothly between the first oil reservoir 16a and the second oil reservoir 16b. A through hole is also formed in the third closing member 14 of the power recovery unit 7 as a communication passage that allows the refrigerating machine oil to pass between the first oil reservoir 16a and the second oil reservoir 16b.

  In the fluid machine 10A of the present embodiment, the following heat flow is formed by the refrigerating machine oil. The refrigeration oil supplied to the main compression mechanism 3 through the oil supply passage in the main compressor shaft 38 by the action of the oil pump 72 is used for lubrication and sealing. At this time, the refrigerating machine oil is heated by the main compression mechanism 3. Thereafter, the refrigerating machine oil is discharged below the bearing member 35 through the oil discharge port 37 and returns to the oil reservoir 16. On the other hand, a part of the refrigerating machine oil is discharged toward the electric motor 8 through the discharge path 40 in a state of being mixed in the refrigerant. The refrigerating machine oil mixed with the refrigerant is heated by the electric motor 8 when passing through the electric motor 8. The refrigerating machine oil is separated from the refrigerant by gravity and centrifugal force, and returns to the oil reservoir 16. By such a process, the refrigerating machine oil returns to the oil reservoir 16, more specifically, the first oil reservoir 16a in a heated state.

  In order to stably supply oil to the main compression mechanism 3, an amount of refrigerating machine oil whose oil level is located above the auxiliary bearing member 71 is accumulated in the oil reservoir 16 in a normal operation state of the refrigeration cycle apparatus 1 </ b> A. It is done. Refrigerating machine oil that has been heated by the main compression mechanism 3 and the electric motor 8 is stored in the first oil reservoir 16a. Therefore, when there is no buffer constituent member 244, the high-temperature refrigeration oil directly contacts the third closing member 14 of the power recovery unit 7, and heat is easily transferred to the low-temperature power recovery unit 7. The sealed container 11 is in contact with the main compression mechanism 3 and the stator 8 b of the electric motor 8. Therefore, heat is transmitted to the refrigerant flowing through the suction pipe 28 and the discharge pipe 31 of the power recovery mechanism 5 using the sealed container 11 as a heat transfer path, or the heat is transferred to the refrigerating machine oil in the second oil reservoir 16b. When heat is transmitted to the refrigerating machine oil in the second oil reservoir 16b, heat convection occurs in the second oil reservoir 16b, and heat is more easily transmitted to the power recovery mechanism 5.

  On the other hand, the heat transfer from the first oil reservoir 16a to the power recovery unit 7 can be suppressed by providing the buffer constituent member 244 below the first oil reservoir 16a as in the present embodiment. Furthermore, a part of the heat that moves from the first oil reservoir 16a toward the power recovery unit 7 can be recovered using the refrigerant flowing through the internal space (buffer 107) of the buffer component 244. Thus, heat transfer from the main compression mechanism 3 that is a high heat source to the power recovery unit 7 that is a low heat source, in particular, to the power recovery mechanism 5 can be suppressed. By recovering the exhaust heat from the main compression mechanism 3 with the refrigerant flowing through the buffer 107, the temperature of the refrigerant discharged from the main compression mechanism 3 rises. Therefore, when the refrigeration cycle apparatus 1A including the fluid machine 10A is applied to a water heater or a heating device, the hot water supply capability and the heating capability are improved.

  From the viewpoint of positively recovering heat with the refrigerant flowing through the buffer 107, a material that is more excellent in heat transfer than the material that forms the sealed container 11 and / or the power recovery unit 7 is used as the material that constitutes the buffer component 244. May be. Generally, the sealed container 11 and the power recovery unit 7 are made of an iron-based material such as carbon steel or cast iron. In this case, the buffer constituent member 244 can be made of a material having a high thermal conductivity, for example, a copper-based material such as brass or an aluminum-based material such as duralumin. By doing so, the thermal resistance from the buffer 107 to the sealed container 11 is reduced, and the effect of recovering heat by the refrigerant flowing through the buffer 107, in other words, the effect of cooling the closed container 11 by the refrigerant flowing through the buffer 107. Becomes higher. In addition, the magnitude of thermal conductivity shall be judged in the temperature range (for example, 0 degreeC-100 degreeC) at the time of operation | movement of 10 A of fluid machines.

  Next, the refrigeration cycle in the refrigeration cycle apparatus 1A will be described. The refrigerant is carbon dioxide. For comparison, the refrigeration cycle without the buffer component 244 will be described first, and then the refrigeration cycle with the buffer component 244 will be described.

  FIG. 7A is a Mollier diagram showing a refrigeration cycle when there is no buffer component 244. The refrigeration cycle in the absence of the buffer component 244 is represented by a-a1-b-c-c1-d-a.

The refrigerant discharged from the discharge port 32e (point a) of the main compression mechanism 3 radiates heat in the internal space 11e of the sealed container 11 and is guided to the inlet (point a1) of the radiator 4. The amount of heat refrigerant loses internal space 11e and q _a. Next, in the radiator 4, the refrigerant gives heat to the surrounding medium (for example, water). The amount of heat released at this time is q _gc . Next, the refrigerant is guided to the power recovery mechanism 5. The refrigerant absorbs part of the heat lost in the internal space 11 e of the sealed container 11 in the suction pipe 28 and the closing member 13 of the power recovery mechanism 5. Therefore, the enthalpy of the refrigerant at the suction port 26 (point b) of the power recovery mechanism 5 assumes that no heat absorption occurs at the suction pipe 28 or the closing member 13 (point b ′). ) Is higher than the enthalpy of the refrigerant. The difference between the refrigerant enthalpy at the suction port 26 (point b ′) of the power recovery mechanism 5 and the refrigerant enthalpy at the suction port 26 (point b) of the power recovery mechanism 5 assuming that there is no heat absorption is q _e1 . To do.

Due to the action of the power recovery mechanism 5, the refrigerant expands to a low temperature and low pressure state. At this time, the energy released from the refrigerant is recovered by the power recovery mechanism 5. The change (point b → point c) at this time has a larger slope than the isentropic line (point b → point ci). Let q _e2 be the difference between the enthalpy of the refrigerant at point c and the enthalpy of the refrigerant at point ci. The refrigerant that has reached the cold / low pressure state in the power recovery mechanism 5 further absorbs part of the heat lost in the internal space 11 e of the sealed container 11 in the discharge pipe 31 and the closing member 13 of the power recovery mechanism 5. Therefore, the enthalpy of the refrigerant at the inlet (point c1) of the evaporator 6 is higher than the enthalpy of the refrigerant at the discharge port 29 (point c) of the power recovery mechanism 5. The difference between the enthalpy of the refrigerant at the inlet (point c1) of the evaporator 6 and the enthalpy of the refrigerant at the discharge port 29 (point c) of the power recovery mechanism 5 is defined as q _e3 .

Assuming that there is no heat exchange between the sealed container 11 and the surrounding medium (air around the sealed container 11), the following relationship is established.
q _a = q _e1 + q _e2 + q _e3

The expanded refrigerant takes heat away from the surrounding medium (for example, air) in the evaporator 6. The endothermic amount at this time is defined as q _eva . Thereafter, the refrigerant is pressurized from the point d to the point e by the sub-compression mechanism 2, and from the point e to the point a by the main compression mechanism 3.

  Next, FIG. 7B shows a refrigeration cycle in the present embodiment. When the buffer constituent member 244 having the buffer 107 is provided, the heat released on the high temperature side (main compression mechanism 3 side) is recovered by the refrigerant flowing through the buffer 107. The refrigeration cycle in this case is represented by a'-a'1-b'-c'-d-fa '.

The heat lost by the refrigerant in the internal space 11 e of the sealed container 11 is recovered by the buffer 107 provided on the refrigerant circuit between the sub compression mechanism 2 and the main compression mechanism 3. A change in state of the refrigerant flowing through the buffer 107 can be represented by a change from the point e to the point f. With the heat recovery in the buffer 107, the state of the refrigerant at the discharge port 32e of the main compression mechanism 3 shifts from the point a to the point a ′, and the state of the refrigerant at the inlet of the radiator 4 also changes from the point a1 to the point a′1. Shift to. The difference between the enthalpy of the refrigerant at point a and the enthalpy of the refrigerant at point a ′ is represented by q _a + dq _m . dq _m −dq _a is an increase in the input of the electric motor 8 due to the shift of the compression stroke to the high enthalpy side. The amount of heat (heat radiation amount) that the refrigerant compressed by the main compression mechanism 3 loses in the internal space 11e of the sealed container 11 is represented by the enthalpy difference q _a + dq _a between the points a ′ and a′1. The amount of heat released to the internal space 11e (q _a + dq _a ) is expected to increase dq _a as compared to the case where the buffer component 244 is not provided. This is because the discharge temperature of the main compression mechanism 3 has increased. Is.

Further, with the heat recovery at the buffer 107, the heat receiving at the suction pipe 28 and the closing member 13 of the power recovery mechanism 5 becomes so small that it can be ignored, so the state of the refrigerant at the suction port 26 of the power recovery mechanism 5 is also from point b. It changes to point b '. Therefore, the amount of heat q _gc ′ dissipated by the radiator 4 is as follows.
_{q gc '= q gc + q} a + q e1 + (dq m -dq a)

As described with reference to FIG. 7A, q _gc is a heat radiation amount when the buffer component 244 is not provided. Thus, the buffer component 244 having the buffer 107 increases the amount of heat dissipated in the radiator 4, that is, improves the heating capability of the radiator 4.

On the other hand, as a result of the refrigerant state at the suction port 26 of the power recovery mechanism 5 shifting from the point b to the point b ′, the refrigerant state at the discharge port 29 of the power recovery mechanism 5 is also shifted from the point c to the point c ′. Assuming that there is no loss other than heat exchange, the change from the point b ′ to the point c ′ is an isentropic change. Further, with the heat recovery in the buffer 107, the heat receiving in the discharge pipe 31 and the closing member 13 of the power recovery mechanism 5 can be ignored, so the endothermic process (point c → point c1) described with reference to FIG. ) Disappears. As a result, the amount of heat q _eva ′ taken from the surroundings by the refrigerant in the evaporator 6 is as shown below.
q _eva '= q _eva + q _e3 + q _c

As described with reference to FIG. 7A, q _eva is an endothermic amount when the buffer component 244 is not provided. q _c (> q _e2 ) is an increase in the amount of heat that accompanies that the refrigerant does not absorb heat from the suction portion (suction pipe 28 and closing member 13) of the power recovery mechanism 5 and the expansion stroke. Thus, the buffer component 244 having the buffer 107 increases the amount of heat absorbed in the evaporator 6, that is, the cooling capacity of the evaporator 6 is improved.

  When the isentropic process is taken into consideration, the power that can be recovered as the expansion work is reduced by shifting the expansion stroke to the low temperature side. On the Mollier diagram, the slope of the point b ′ → the point c ′ is larger than that of the isentropic line (the point b → the point ci). Therefore, the compression work performed by the sub-compression mechanism 2 is smaller than the difference between the refrigerant enthalpy at the point e and the refrigerant enthalpy at the point f multiplied by the flow rate, but is reflected in FIG. 7B for simplicity. I have not let it.

  As described above, by providing the buffer constituent member 244 having the buffer 107, the heat transfer can be restricted to the compression stroke side (the main compression stroke by the main compression mechanism 3 and the sub compression stroke by the sub compression mechanism 2). Therefore, the heat reception of the power recovery mechanism 5 can be reduced, and the discharge temperature of the main compression mechanism 3 can be increased. As a result, the heating capacity and cooling capacity of the refrigeration cycle apparatus 1A can be improved.

<< Other functions and effects >>
In the present embodiment, the power recovery unit 7 is disposed in an oil reservoir 16 provided in the sealed container 11 and in which refrigeration oil supplied to the main compression mechanism 3 is stored. By doing in this way, the oil sump which supplies refrigerating machine oil to the main compression mechanism 3 and the power recovery unit 7 can be put together.

  For example, when an oil sump for the power recovery unit 7 is provided separately from the oil sump for the main compression mechanism 3, the refrigeration oil that has flowed out of the one oil sump into the refrigerant circuit 9 returns to the other oil sump, There is a risk that the amount of refrigerating machine oil stored in one oil reservoir will decrease. If so, there is a risk that the main compression mechanism 3 or the power recovery unit 7 will not be sufficiently lubricated or sealed.

  On the other hand, when the oil reservoirs of the main compression mechanism 3 and the power recovery unit 7 are made common as in this embodiment, even if the refrigeration oil flows out from the oil reservoir 16 to the refrigerant circuit 9, it flows out. The refrigerating machine oil returns to the oil reservoir 16 again through the refrigerant circuit 9. Therefore, it is possible to suppress a decrease in the amount of the refrigerating machine oil stored in the oil reservoir 16. As a result, the refrigeration oil can be stably supplied to the main compression mechanism 3 and the power recovery unit 7. Therefore, the reliability of the refrigeration cycle apparatus 1A can be improved by appropriate lubrication of the sliding portions of the main compression mechanism 3 and the power recovery unit 7. Moreover, since it becomes possible to seal the leak clearance of the main compression mechanism 3 or the power recovery unit 7 with high certainty, the operating efficiency of the refrigeration cycle apparatus 1A can be improved.

  In the present embodiment, the refrigerant from the main compression mechanism 3 is discharged into the sealed container 11, and the refrigerating machine oil is separated from the refrigerant in the sealed container 11. The separated refrigerating machine oil returns to the oil reservoir 16 again. Thus, since the refrigeration oil mixed in the refrigerant is separated from the refrigerant in the sealed container 11 and returns to the oil reservoir 16, the reduction of the refrigeration oil accumulated in the oil reservoir 16 is more effectively suppressed. As a result, the refrigeration oil can be supplied to the main compression mechanism 3 and the power recovery unit 7 more stably.

  Further, the refrigerant compressed by the main compression mechanism 3 is temporarily discharged into the sealed container 11, whereby the pressure in the sealed container 11 can be made relatively high. As a result, refrigerating machine oil is easily supplied to the main compression mechanism 3 via an oil supply hole (not shown) formed in the main compressor shaft 38. Further, penetration of the refrigeration oil into the power recovery unit 7 is also promoted. As a result, the refrigeration oil can be more reliably supplied to the main compression mechanism 3 and the power recovery unit 7. Thereby, the reliability of the refrigeration cycle apparatus 1A is further improved, and the operation efficiency of the refrigeration cycle apparatus 1A is further improved.

  Further, by sharing the oil reservoirs of the main compression mechanism 3 and the power recovery unit 7, each oil reservoir is provided for the power recovery unit 7 separately from the oil reservoir for the main compression mechanism 3. A special mechanism such as an oil equalizing pipe for balancing the amount of refrigerating machine oil accumulated in the reservoir becomes unnecessary. Therefore, the configuration of the refrigeration cycle apparatus 1A can be simplified and the manufacturing cost can be reduced.

  Furthermore, by disposing the power recovery unit 7 in the oil reservoir 16, a separate sealed container for the power recovery unit 7 becomes unnecessary. Accordingly, the refrigeration cycle apparatus 1A can be reduced in size and cost. Further, by using the first closing member 15 in common for the power recovery mechanism 5 and the sub-compression mechanism 2, the fluid machine 10A and thus the refrigeration cycle apparatus 1A can be further downsized.

  Further, if the power recovery unit 7 is disposed in the oil reservoir 16 as in the present embodiment, it is only necessary to change one or both of the body shell 11a and the bottom shell 11c of the sealed container 11, and the main compression mechanism There is no need to change the third design. In other words, the main compression mechanism 3 can be freely designed regardless of the power recovery unit 7. Therefore, a high degree of freedom can be realized. Further, the configuration of the present embodiment can be adopted only by changing the shape of the sealed container 11 and without changing other designs so much, so that the design cost can be reduced. It is also relatively easy to share parts with other refrigeration cycle apparatuses. As a result, further cost reduction of the refrigeration cycle apparatus 1A can be realized.

  In the present embodiment, the main compressor shaft 38 of the main compression mechanism 3 and the power recovery shaft 12 of the power recovery unit 7 are separate. For this reason, the design freedom of the main compression mechanism 3 and the power recovery unit 7 becomes higher. As a result, further cost reduction can be achieved.

  Further, according to this configuration, it is necessary to arrange the main compressor shaft 38 and the power recovery shaft 12 so that the axis of the main compressor shaft 38 and the axis of the power recovery shaft 12 are located on a straight line. Disappear. Therefore, the degree of freedom of arrangement of the main compression mechanism 3 and the power recovery unit 7 is also improved. As a result, the design freedom of the fluid machine 10A is improved. In some cases, further downsizing can be achieved. However, it is advantageous to reduce vibration and noise by matching the central axis of the main compressor shaft 38 and the central axis of the power recovery shaft 12 as in this embodiment.

  From the viewpoint of improving the degree of freedom of design, the power recovery unit 7 is fixed to the sealed container 11 without directly fixing the main compression mechanism 3 and the electric motor 8 and the power recovery unit 7 as in the present embodiment. Is preferred. By doing so, it becomes easier to share the unit of the power recovery unit 7, the main compression mechanism 3, and the electric motor 8 with the other refrigeration cycle apparatus 1A. Therefore, the development cost and the manufacturing cost can be further reduced.

  In the present embodiment, since the power recovery unit 7 is fixed to the trunk shell 11a, the design freedom of the upper shell 11b and the bottom shell 11c is very high. Since the trunk shell 11a is cylindrical, it is easy to make the height relatively high. Accordingly, by fixing the power recovery unit 7 to the shell shell 11a, a particularly high degree of design freedom can be realized.

  Further, by fixing the power recovery unit 7 to the shell shell 11a, the main compression mechanism 3 is also fixed to the shell shell 11a, thereby reducing the error in the distance between the suction pipe 32c and the discharge pipe 51. Can do. For this reason, attachment of the connecting pipe 70 can be facilitated. As a result, further cost reduction of the refrigeration cycle apparatus 1A is realized. The positional relationship between the main compression mechanism 3 and the buffer constituent member 244 may be set so that the connection between the suction pipe 32c and the discharge pipe 51 is easiest. For example, the position of the suction pipe 32c in the circumferential direction of the shaft 38 and the position of the discharge pipe 51 are preferably matched.

  In addition, by using the communication pipe 70 disposed outside the sealed container 11, the suction pipe 32 c and the discharge pipe 51 can be easily connected regardless of the configuration of the main compression mechanism 3 and the power recovery unit 7. Moreover, according to this structure, since the design change of the structure in the airtight container 11 becomes substantially unnecessary, it becomes easy to make the main compression mechanism 3 and the power recovery unit 7 common with the other refrigeration cycle apparatuses 1A.

  In the present embodiment, power is recovered by the power recovery mechanism 5. The power recovered by the power recovery mechanism 5 is used as power for the sub-compression mechanism 2. For this reason, high energy efficiency is realized. For example, in the refrigeration cycle apparatus in which the sub compression mechanism 2 is not disposed, the main compression mechanism 3 compresses the refrigerant from the point d to the point a. On the other hand, in the refrigeration cycle apparatus 1A of the present embodiment provided with the sub compression mechanism 2 connected to the power recovery mechanism 5, the refrigerant is boosted from point d to point e by being discharged from the sub compression mechanism 2. Is done. For this reason, the main compression mechanism 3 should just compress a refrigerant | coolant from the point e to the point a. Therefore, the work amount of the main compression mechanism 3 can be reduced by an energy corresponding to the difference between the enthalpy of the refrigerant at the point e and the enthalpy of the refrigerant at the point d. As a result, the COP (coefficient of performance) of the refrigeration cycle apparatus 1A can be improved.

  In the case where carbon dioxide is used as the refrigerant, the difference between the pressure in the radiator 4 and the pressure in the evaporator 6 is relatively large. For this reason, when carbon dioxide is used as a refrigerant, a relatively large energy can be recovered by disposing the power recovery mechanism 5 between the radiator 4 and the evaporator 6 as in the present embodiment. High energy efficiency can be realized.

  By the way, it is conceivable to recover the power by connecting the power recovery shaft 12 of the power recovery mechanism 5 to the main compression mechanism 3 without arranging the sub-compression mechanism 2. However, the main compression mechanism 3 is very hot compared to the power recovery mechanism 5. For this reason, when the main compression mechanism 3 and the power recovery mechanism 5 are connected, heat exchange is easily performed between the main compression mechanism 3 and the power recovery mechanism 5. Specifically, the temperature of the main compression mechanism 3 is lowered. As a result, the COP of the refrigeration cycle apparatus 1A decreases. On the other hand, the sub compression mechanism 2 is not as hot as the main compression mechanism 3. For this reason, when the sub compression mechanism 2 and the power recovery mechanism 5 are connected, heat exchange does not occur as much as when the power recovery mechanism 5 and the main compression mechanism 3 are connected. Therefore, as in the present embodiment, the sub compression mechanism 2 is provided separately from the main compression mechanism 3, and the sub compression mechanism 2 and the power recovery mechanism 5 are connected to reduce the COP of the refrigeration cycle apparatus 1A. Can be suppressed. In other words, the energy efficiency of the refrigeration cycle apparatus 1A can be improved.

  In the present embodiment, the sub-compression mechanism 2 is disposed near the relatively high temperature main compression mechanism 3, and the relatively low-temperature power recovery mechanism 5 is further away from the main compression mechanism 3 than the sub-compression mechanism 2. Placed in position. In other words, the power recovery unit 7 is disposed in the oil reservoir 16 in a posture in which the sub compression mechanism 2 is positioned between the buffer 107 and the power recovery mechanism 5. Therefore, heat exchange between the main compression mechanism 3 and the power recovery mechanism 5 is effectively suppressed.

  In the present embodiment, the power recovery unit 7 is fixed to the sealed container 11 in the sub-compression mechanism 2. Specifically, the third closing member 14 is fixed to the sealed container 11. For this reason, the heat from the sealed container 11 is not directly transmitted to the power recovery mechanism 5 but is transmitted via the sub-compression mechanism 2. Therefore, the sub-compression mechanism 2 becomes a thermal resistance, and heat conduction to the power recovery mechanism 5 via the sealed container 11 is effectively suppressed.

  Unlike the power recovery mechanism 5, the sub-compression mechanism 2 does not have a big problem even if the temperature rises somewhat. When heat transfer occurs from the main compression mechanism 3 to the sub-compression mechanism 2, the energy imparted to the refrigerant in the main compression mechanism 3 is reduced by that amount, but the amount of heat transferred to the sub-compression mechanism 2 is discharged from the sub-compression mechanism 2. The temperature of the refrigerant to be increased. In other words, although the energy imparted to the refrigerant in the main compression mechanism 3 decreases, the energy imparted to the refrigerant in the sub-compression mechanism 2 increases, and a higher temperature refrigerant is supplied to the main compression mechanism 3. Become. That is, even if heat transfer occurs from the main compression mechanism 3 to the sub compression mechanism 2, the decrease in energy imparted to the refrigerant by the main compression mechanism 3 is substantially due to the increase in energy imparted to the refrigerant by the sub compression mechanism 2. Therefore, the COP of the refrigeration cycle apparatus 1A does not decrease so much.

  An electric motor 8 is disposed between the main compression mechanism 3 and the sub compression mechanism 2. For this reason, the power recovery mechanism 5 is further away from the main compression mechanism 3. Accordingly, heat exchange between the main compression mechanism 3 and the power recovery mechanism 5 is more effectively suppressed.

  In the present embodiment, the oil pump 72 is disposed at the lower end of the main compressor shaft 38. By configuring in this way, the main compression mechanism 3 having a relatively high temperature can be moved away from the oil reservoir 16. As a result, the temperature rise of the oil reservoir 16 can be prevented. Therefore, the temperature rise of the power recovery mechanism 5 disposed in the oil reservoir 16 can be suppressed. Therefore, the COP of the refrigeration cycle apparatus 1A can be further improved.

  In the present embodiment, the sub-compression mechanism 2 and the power recovery mechanism 5 are each a fluid pressure motor. However, each of the sub-compression mechanism 2 and the power recovery mechanism 5 compresses or expands the sucked refrigerant. The refrigerant may be discharged after performing the stroke. That is, the sub compression mechanism 2 and the power recovery mechanism 5 may each have a specific volume ratio. However, the fluid pressure motor has a simple configuration as compared with the compression mechanism in which the compression stroke is performed and the expansion mechanism in which the expansion stroke is performed. Therefore, by using the sub-compression mechanism 2 and the power recovery mechanism 5 as fluid pressure motors, the configuration of the fluid machine 10A can be further simplified and downsized. As a result, the refrigeration cycle apparatus 1A can be further simplified, reduced in size, and reduced in cost. From the viewpoint of simplification, miniaturization, and cost reduction, it is particularly preferable that the sub-compression mechanism 2 and the power recovery mechanism 5 are each a rotary fluid pressure motor.

  Thus, the capacity of the oil reservoir 16 can be reduced by reducing the size of the power recovery unit 7. Thereby, the amount of refrigerating machine oil stored in the oil reservoir 16 can also be reduced. As a result, the oil level of the oil reservoir 16 can be further stabilized. Therefore, the refrigeration oil can be more reliably supplied to the main compression mechanism 3 and the power recovery unit 7.

  Further, each of the sub-compression mechanism 2 and the power recovery mechanism 5 is configured by a fluid pressure motor, so that both the waveform of the recovery torque by the power recovery mechanism 5 and the waveform of the load torque of the sub-compression mechanism 2 are A substantially sinusoidal shape with a rotation angle of 360 ° as one cycle can be obtained. As a result, the power recovery shaft 12 rotates smoothly without decelerating. Therefore, energy recovery efficiency can be improved. Moreover, generation | occurrence | production of the vibration and noise in 1 A of refrigeration cycle apparatuses can be suppressed.

  Specifically, by synchronizing the timing at which the first piston 21 of the power recovery mechanism 5 is located at the top dead center with the timing at which the second piston 41 of the sub compression mechanism 2 is located at the top dead center, The waveform and the waveform of the recovery torque can be matched with each other. In other words, the ratio between the load torque and the recovery torque is substantially constant at any rotation angle of the power recovery shaft 12. Accordingly, uneven rotation speed of the shaft can be suppressed. As a result, the energy efficiency of the refrigeration cycle apparatus 1A can be further improved. Moreover, since the rotational speed unevenness of the shaft can be suppressed, vibration and noise of the refrigeration cycle apparatus 1A can also be suppressed.

  More specifically, in the present embodiment, the direction in which the first partition member 24 is disposed with respect to the power recovery shaft 12 and the direction in which the second partition member 44 is disposed with respect to the power recovery shaft 12 are mutually determined. Power recovery is achieved by making the eccentric direction of the first piston 21 with respect to the central axis of the first cylinder 22 and the eccentric direction of the second piston 41 with respect to the central axis of the second cylinder 42 substantially the same. The timing at which the first piston 21 of the mechanism 5 is located at the top dead center is synchronized with the timing at which the second piston 41 of the sub compression mechanism 2 is located at the top dead center. By doing in this way, manufacture of fluid machine 10A becomes easy.

  Further, by making the eccentric direction of the first piston 21 with respect to the central axis of the first cylinder 22 and the eccentric direction of the second piston 41 with respect to the central axis of the second cylinder 42 substantially the same, the power recovery shaft 12, The frictional force between the second closing member 13 and the third closing member 14 supporting the power recovery shaft 12 can be reduced.

  Specifically, the first piston 21 of the power recovery mechanism 5 is subjected to a differential pressure from the relatively high pressure suction working chamber 23a toward the relatively low pressure discharge working chamber 23b. Similarly, a differential pressure from the relatively high pressure discharge working chamber 43b to the relatively low pressure suction working chamber 43a acts on the second piston 41 of the sub-compression mechanism 2. These differential pressures push the power recovery shaft 12 through the eccentric portions 12b and 12c, and act on the bearing portions of the second closing member 13 and the third closing member 14 that pivotally support the power recovery shaft 12. As a result, a rotation inhibiting force is generated on the power recovery shaft 12, and the wear of the power recovery shaft 12 and the wear of the bearing portion are promoted. On the other hand, in the present embodiment, the first piston 21 and the second piston 41 have opposite pressure directions. For this reason, the differential pressure cancels between the first piston 21 and the second piston 41. As a result, the frictional force between the power recovery shaft 12 and the second closing member 13 and the third closing member 14 can be reduced. Therefore, power required for rotating the power recovery shaft 12 can be reduced, and energy recovery can be improved. In addition, wear of the power recovery shaft 12, the second closing member 13, and the third closing member 14 can be suppressed.

  Further, the form of the buffer constituent member and the buffer formed therein is not limited to that shown in FIG. Hereinafter, another embodiment in which the buffer and the buffer constituent member forming the buffer are changed will be described. Members common to the embodiment shown in FIG. 1 are denoted by common reference numerals, and description thereof is omitted.

(Second Embodiment)
FIG. 8 is a longitudinal sectional view of the fluid machine according to the second embodiment. The fluid machine 10 </ b> B includes a buffer component 247 disposed between the main compression mechanism 3 and the power recovery unit 7. The buffer constituent member 247 is provided adjacent to the power recovery unit 7. The buffer component member 247 partitions the oil reservoir 16 into a first oil reservoir 16a located on the main compression mechanism 3 side and a second oil reservoir 16b located on the power recovery unit 7 side. Inside the buffer component 247, the buffer 107 described in the first embodiment and the branch buffer 108 branched from the buffer 107 are formed. The branch buffer 108 is connected to the buffer 107 inside the buffer constituent member 247, and can be filled with the refrigerant that should flow through the buffer 107, that is, the refrigerant that has been pressurized by the sub-compression mechanism 2.

  FIG. 9 shows an exploded perspective view of the buffer constituent member 247. As shown in FIG. 9, the buffer constituting member 247 includes an upper buffer member 245 and a lower buffer member 246 disposed adjacent to the upper buffer member 246. The outer diameters of the upper buffer member 245 and the lower buffer member 246 coincide with the inner diameter of the sealed container 11. The lower buffer member 246 is configured by a bowl-shaped member having a disk-shaped bottom portion 246a and an annular side portion 246b rising from the outer peripheral portion of the bottom portion 246a. A space surrounded by the bottom portion 246a and the annular side portion 246b is the buffer 107. The lower buffer member 246 has substantially the same structure as that of the first embodiment, but is different in that a groove 246k as a communication passage for refrigerating machine oil is formed on the outer peripheral surface of the side portion 246b. Further, in the lower buffer member 246, a through hole 246j for inserting the discharge pipe 51 is provided in the side portion 246b, and a through hole 246h for relaying the discharge path 50 of the sub compression mechanism 2 and the buffer 107 is provided in the bottom portion 246a. Is formed.

  The upper buffer member 245 has a disk-shaped bottom portion 245a and an annular side portion 245b that rises from the outer periphery of the bottom portion 245a. A plurality of through holes 108 are formed in the side portion 245b of the upper buffer member 245 so as to penetrate the side portion 245b in the axial direction (height direction). These through holes 108 are connected to the buffer 107 of the lower buffer member 246 in the vertical direction and function as the branch buffer 108. The upper surface 245p of the side portion 245b of the upper buffer member 245 is in contact with the lower surface 71q of the auxiliary bearing member 71, and the branch buffer 108 is sealed by the lower surface 71q of the auxiliary bearing member 71. A space surrounded by the side portion 245b of the upper buffer member 245 becomes the first oil reservoir 16a. The refrigerating machine oil after lubricating the main compression mechanism 3 returns to the first oil reservoir 16a through the opening 71a of the auxiliary bearing member 71.

  The side portion 245b of the upper buffer member 245 has a shape in which a part in the circumferential direction is cut away. Further, a groove 245k is formed by cutting out a part of the bottom 245a so that the side 245b faces the cut-out portion. The groove 245k is connected to the groove 246k formed in the side portion 246b of the lower buffer member 246 in the axial direction (up and down direction), so that the refrigerating machine oil flows between the first oil reservoir 16a and the second oil reservoir 16b. The communication passages 245k and 246k that allow the The amount of oil between the first oil reservoir 16a and the second oil reservoir 16b is automatically adjusted by the communication passages 245k and 246k.

  Also in this embodiment, the same effect as described in the first embodiment, that is, heat is recovered by the refrigerant filling the buffer 107 inside the buffer constituent member 247 and is transferred from the first oil reservoir 16a to the power recovery mechanism 5. The effect of suppressing the heat transfer is obtained. Furthermore, according to the present embodiment, the branch buffer 108 extends in the oil surface direction along the inner peripheral surface of the sealed container 11 and surrounds the first oil reservoir 16a in the circumferential direction. The outer diameter of the buffer constituent member 247 matches the inner diameter of the sealed container 11, and the outer peripheral surface of the buffer constituent member 247 is in surface contact with the inner peripheral surface of the sealed container 11. Therefore, compared with 1st Embodiment, the airtight container 11 heated by the main compression mechanism 3 or the electric motor 8 can be positively cooled.

  The heat transfer from the main compression mechanism 3 side, which is a high heat source, to the power recovery unit 7 side, which is a low heat source, occurs using mechanical structural parts such as the power recovery shaft 12 and the closing member 14 as a heat transfer path, The refrigerating machine oil stored in the second oil reservoir 16b is used as a heat transfer path. When the improvement which expands the contact length of the axial direction of the buffer structural member 247 and the airtight container 11 is given like this embodiment, in order to suppress the heat transfer which uses the airtight container 11 as a heat-transfer path | route, It is advantageous. In other words, by increasing the contact area between the buffer component 247 and the sealed container 11, heat that moves from the main compression mechanism 3 side toward the power recovery unit 7 side with the sealed container 11 as a heat transfer path can be efficiently obtained. It becomes possible to collect.

  In the present embodiment, the upper buffer member 245 and the lower buffer member 246 form the buffer constituent member 247. However, as long as the buffer 107 and the branch buffer 108 can be formed, the shape of the buffer constituent member and the number of parts Is not particularly limited. For example, the upper buffer member 245 may be composed of a plurality of parts. For example, the bottom portion 245a may be configured with one component, and the side portion 245b having the branch buffer 108 may be configured with a pair of components. By doing so, the contact between the portion where the branch buffer 108 is formed and the sealed container 11 becomes good, and the heat recovery efficiency by the branch buffer 108 is improved.

(Third embodiment)
FIG. 10 is a longitudinal sectional view of a fluid machine according to a third embodiment. The fluid machine 10C includes a second buffer constituent member 248 in addition to the buffer constituent member 247 (first buffer constituent member 247) described in the second embodiment. In other respects, the present embodiment is common to the second embodiment.

  As shown in FIG. 10, the first buffer constituting member 247 having the buffer 107 and the branch buffer 108 is provided adjacent to the upper surface of the third closing member 14 constituting the power recovery unit 7. On the other hand, the second buffer component 248 having the branch buffer 109 is provided adjacent to the lower surface of the third closing member 14. The branch buffer 109 inside the second buffer constituent member 248 is filled with the refrigerant that should flow through the buffer 107 of the first buffer constituent member 247 so that the discharge path 50 and the branch discharge path inside the third closing member 14 are filled. The first buffer constituent member 247 is connected to the buffer 107 via 50a. Further, the branch buffer 109 extends in the direction of the bottom surface along the inner peripheral surface of the sealed container 11 and surrounds the oil reservoir 16 (second oil reservoir 16b) in the circumferential direction around the power recovery unit 7.

  FIG. 11 is a perspective view of the second buffer component 248. As shown in FIG. 11, the second buffer component 248 has an annular shape. A power recovery unit 7 is disposed in the central space. A plurality of bottomed holes 109 as branch buffers 109 are formed so as to surround the central space portion. The outer diameter of the second buffer component 248 matches the inner diameter of the sealed container 11, and the outer peripheral surface of the second buffer component 248 is in surface contact with the inner peripheral surface of the sealed container 11.

  As shown in FIG. 10, a branch discharge path 50 a branched from the discharge path 50 is formed inside the third closing member 14 of the power recovery unit 7. The branch discharge path 50 a and the branch buffer 109 inside the second buffer component 248 overlap vertically, and the refrigerant whose pressure has been increased by the sub-compression mechanism 2 is guided to the branch buffer 109. In addition, a groove 248k is formed at the upper end of the second buffer component 248 as a communication passage that allows the oil to pass between the first oil reservoir 16a and the second oil reservoir 16b. The second buffer constituent member 248 may be configured as an assembly of a plurality of parts. By doing so, it becomes easy to improve the adhesion between the second buffer component 248 and the sealed container 11. If the adhesion is improved, the thermal resistance is reduced, and heat is easily transferred from the sealed container 11 to the second buffer component 248.

  According to the present embodiment, heat can be more effectively suppressed from moving to the refrigerating machine oil in the second oil reservoir 16a using the sealed container 11 as a heat transfer path, and heat can be recovered with the refrigerant filling the branch buffer 109. Can do. This effect is obtained by superimposing the effect described in the first embodiment and the second embodiment. In the present embodiment, the buffer component 248 is disposed only on the side surface of the sealed container 11, but may be disposed on the bottom surface of the sealed container 11 in order to further enhance the effect of suppressing heat transfer.

(Fourth embodiment)
FIG. 13 is a longitudinal sectional view of a fluid machine according to the fourth embodiment, and FIG. 12 is a configuration diagram of a refrigeration cycle apparatus using the fluid machine. As shown in FIG. 12, the refrigeration cycle apparatus 1B includes a main compression mechanism 3, a radiator 4, a power recovery mechanism 5, an evaporator 6, an upstream buffer 112 (upstream portion), a sub compression mechanism 2, and a downstream buffer 113. (Downstream part). These elements are connected in this order, and the refrigerant circuit 9 is formed. That is, in this embodiment, buffers are provided on both the upstream side and the downstream side of the sub-compression mechanism 2. The upstream buffer 112 forms a suction path for guiding the refrigerant to the suction port 46 of the sub compression mechanism 2. The downstream buffer 113 forms a discharge path for the refrigerant discharged from the discharge port 49 of the sub compression mechanism 2. The upstream buffer 112 has a role of expanding the cross-sectional area of the flow path beyond the opening area of the suction port 46. The downstream buffer 113 has a role of expanding the cross-sectional area of the flow path beyond the opening area of the discharge port 49. The upstream buffer 112 and the downstream side 113 recover exhaust heat from the main compression mechanism 3 that is a high heat source, and suppress heat transfer to the power recovery unit 7 that is a low heat source (particularly, the power recovery mechanism 5). Is done.

  As shown in FIG. 13, in the fluid machine 10 </ b> D of the present embodiment, an upstream buffer 112 and a downstream buffer 113 are provided between the main compression mechanism 3 and the power recovery unit 7 in the axial direction of the power recovery shaft 12. A buffer component 232 having an internal space is provided adjacent to the power recovery unit 7. The buffer constituent member 232 includes an upper buffer member 230 and a lower buffer member 231. The upper buffer member 230 is configured by a disk-shaped member. The lower buffer member 231 is configured by a bowl-shaped member that is closed by the upper buffer member 230.

  FIG. 14 is a perspective view of the lower buffer member 231 of the buffer component 232. The lower buffer member 231 extends from the disc-shaped bottom portion 251, the annular side portion 250 rising in the axial direction from the outer peripheral portion of the bottom portion 251, the bearing portion 253 provided in the center portion, and the bearing portion 253 toward the side portion 250. Two partition parts 252L and 252R are included. An annular space around the bearing portion 253 is partitioned into an upstream buffer 112 and a downstream buffer 113 by partition portions 252L and 252R. In other words, the internal space of the buffer component 232 is partitioned so that the upstream buffer 112 is formed on one side and the downstream buffer 113 is formed on the other side with the bearing portion 253 as a boundary. Each of the buffers 112 and 113 has a substantially fan shape when viewed in plan from the axial direction.

  A suction port 46 and a discharge port 49 of the sub compression mechanism 2 are formed in the bottom portion 251. The suction port 46 faces the upstream buffer 112, and the discharge port 49 faces the downstream buffer 113. In the side portion 250, a through hole 250 h for inserting the suction pipe 48 is located at a position facing the upstream buffer 112, and a through hole 250 j for inserting the discharge pipe 51 is located at a position facing the downstream buffer 113. Each is formed. Further, a groove 250k is formed on the outer peripheral surface of the side portion 250 as a communication passage that allows the oil to come and go between the first oil reservoir 16a and the second oil reservoir 16b.

  As shown in FIG. 12, in this embodiment, a portion corresponding to the third closing member 14 in the first to third embodiments is omitted. That is, the buffer constituent member 232 is also used as a closing member that closes the bearing of the power recovery shaft 12 and the sub compression mechanism 2. Therefore, an effect of suppressing heat transfer from the main compression mechanism 3 side to the power recovery unit 7 side by collecting heat by the refrigerant flowing through the buffers 112 and 113 can be obtained without substantially increasing the number of parts. . In order to sufficiently obtain such an effect, the cross-sectional area perpendicular to the refrigerant flow direction of the upstream buffer 112 is larger than the opening area of the suction port 46, and the same cross-sectional area of the downstream buffer 113 is larger than the opening area of the discharge port 49. It should be wide. In the first to third embodiments, the cross-sectional area of the discharge path 50 of the third closing member 14 is small. Therefore, the effect of heat recovery cannot be expected with only the third closing member 14.

  Next, the refrigeration cycle in the refrigeration cycle apparatus 1B shown in FIG. 12 will be described. The refrigeration cycle in the refrigeration cycle apparatus 1B is represented by a'-a'1-b'-c'-dd "-e" -f "-a 'as shown in the Mollier diagram of FIG. .

The refrigerant compressed by the main compression mechanism 3 loses the amount of heat (q _a + dq _a ) lost in the internal space 11 e of the sealed container 11, the amount of heat q _u recovered by the upstream buffer 112, and is recovered by the downstream buffer 113. between the heat q _d, the following relationship is established.
q _a + dq _a = q _u + q _d

Similarly to the first embodiment, the heat dissipation amount q _gc ′ of the refrigerant in the radiator 4 and the heat absorption amount q _eva ′ of the refrigerant in the evaporator 6 are as follows.
_{q gc '= q gc + q} a + q e1 + (dq m -dq a)
q _eva '= q _eva + q _e3 + q _c

  As described above, even when the buffers 112 and 113 are provided on the upstream side and the downstream side of the sub-compression mechanism 2, the same effect as that of the first embodiment can be obtained.

  In addition, according to the present embodiment, since the buffer 112 is provided on the upstream side of the sub compression mechanism 2, it is possible to prevent the liquid refrigerant from being sucked into the sub compression mechanism 2. This is because when the refrigerant going from the evaporator 6 to the sub-compression mechanism 2 contains liquid refrigerant, the liquid refrigerant receives heat and vaporizes when it flows through the upstream buffer 112. By preventing liquid compression, the efficiency and reliability of the sub-compression mechanism 2 are increased.

(Fifth embodiment)
FIG. 16 is a longitudinal sectional view of a fluid machine according to a fifth embodiment. This embodiment is a combination of the second embodiment and the fourth embodiment. Therefore, the effects obtained in the second and fourth embodiments can be obtained in a superimposed manner.

  As shown in FIG. 16, the buffer component 260 in the fluid machine 10E is configured by the upper buffer member 245 described in the second embodiment and the lower buffer member 231 described in the fourth embodiment. An upstream buffer 112 and a downstream buffer 113 are formed in the lower buffer member 231. A first branch buffer 108 a and a second branch buffer 108 b are formed inside the upper buffer member 245. That is, half of the plurality of through holes 108 included in the upper buffer member 245 described with reference to FIG. 9 overlaps the upper buffer 112 in the upper and lower directions, and is filled with the refrigerant to be compressed by the sub compression mechanism 2. The buffer 108a becomes the second branch buffer 108b in which the remaining half overlaps with the downstream buffer 113 in the vertical direction and is filled with the refrigerant compressed by the sub compression mechanism 2.

(Sixth embodiment)
FIG. 17 is a longitudinal sectional view of a fluid machine according to a sixth embodiment. This embodiment is a combination of the third embodiment and the fourth embodiment. Therefore, the effects obtained in the third and fourth embodiments can be obtained in a superimposed manner.

  As shown in FIG. 16, the buffer component 270 in the fluid machine 10 </ b> F is described in the upper buffer member 245 described in the third embodiment, the lower buffer member 231 described in the fourth embodiment, and the third embodiment. A portion corresponding to the second buffer constituent member 248 (referred to as an auxiliary buffer member 248). According to the present embodiment, since the buffer component member 270 is also used as a closing member that closes the sub compression mechanism 2 and a bearing of the power recovery shaft 12, the auxiliary buffer member 248 is provided adjacent to the lower buffer member 231. There is an advantage that can be.

  Inside the auxiliary buffer member 248, a third branch buffer 109a and a fourth branch buffer 109b are formed. That is, half of the plurality of bottomed holes 109 included in the auxiliary buffer member 248 (second buffer constituent member in the third embodiment) described with reference to FIG. The third branch buffer 109a is filled with the refrigerant to be compressed at 2, and the remaining half overlaps with the downstream buffer 113 at the top and bottom, and the fourth branch buffer 109b is filled with the refrigerant compressed by the sub compression mechanism 2. Become. The lower buffer member 231 includes a passage 231c (for example, a through hole) that relays the upstream buffer 112 and the third branch buffer 109a, and a passage 231d (for example, a through hole) that relays the downstream buffer 113 and the fourth branch buffer 109. ) And are formed.

(Seventh embodiment)
FIG. 18 is a configuration diagram of a refrigeration cycle apparatus in which a buffer is provided between the evaporator and the sub compression mechanism in the refrigerant circuit. As shown in FIG. 18, the refrigeration cycle apparatus 1C includes a main compression mechanism 3, a radiator 4, a power recovery mechanism 5, an evaporator 6, a buffer 105, and a sub compression mechanism 2. These elements are connected in this order, and the refrigerant circuit 9 is formed. That is, in the present embodiment, the buffer 105 is provided on the upstream side of the sub compression mechanism 2. The buffer 105 forms a flow path (suction path) for guiding the refrigerant to the suction port 46 of the sub compression mechanism 2 and has a function of expanding the cross-sectional area of the flow path. The buffer 105 collects exhaust heat from the main compression mechanism 3 that is a high heat source and suppresses heat transfer to the power recovery unit 7 that is a low heat source (particularly, the power recovery mechanism 5).

A refrigeration cycle in the refrigeration cycle apparatus 1C shown in FIG. 18 will be described. Refrigeration cycle in the refrigeration cycle apparatus 1C, as shown in the Mollier diagram of FIG. 19, represented by a'-a'1-b'-c'- d-d 3 -e 3 -a '.

The amount of heat that the refrigerant compressed by the main compression mechanism 3 loses in the internal space 11e of the sealed container 11 is represented by (q _a + dq _a ). This heat is recovered in the buffer 105. That is, as shown in FIG. 19, the enthalpy of the refrigerant at the suction port 46 (point d ₃ ) of the sub-compression mechanism 2 is obtained by adding the heat quantity (q _a + dq _a ) to the enthalpy without the buffer 105. . Similarly, the state of the refrigerant at the discharge port 32e (point a ′) of the main compression mechanism 3 is also shifted to the high enthalpy side.

Therefore, the heat dissipation amount q _gc ′ of the refrigerant in the radiator 4 and the heat absorption amount q _eva ′ of the refrigerant in the evaporator 6 are as follows, as in the first embodiment.
_{q gc '= q gc + q} a + q e1 + (dq m -dq a)
q _eva '= q _eva + q _e3 + q _c

  Thus, even when the buffer 105 is provided on the upstream side of the sub-compression mechanism 2, the same effect as that of the first embodiment in which the buffer is provided on the downstream side can be obtained. That is, a configuration in which a buffer is provided on the upstream side of the sub-compression mechanism 2 may be employed in the second embodiment or the third embodiment. Further, according to the present embodiment, since the buffer 105 is provided on the upstream side of the sub-compression mechanism 2, the effect of preventing liquid compression can be obtained as in the fourth embodiment.

  Further, according to each embodiment of the present invention, since the buffer is provided on the refrigerant circuit, an effect of attenuating pressure pulsations generated from the main compression mechanism 3, the sub compression mechanism 2, and the power recovery mechanism 5 can be expected.

  The refrigeration cycle apparatus provided with the fluid machine of the present invention can be applied to a water heater, an air conditioner, a heating device, and the like.

Sectional drawing of the fluid machine concerning 1st Embodiment of this invention. Configuration diagram of a refrigeration cycle apparatus using the fluid machine shown in FIG. III-III arrow view in FIG. IV-IV arrow view in Fig. 1 Operation principle diagram of power recovery mechanism Operation principle diagram of sub-compression mechanism Mollier diagram showing refrigeration cycle when no buffer component is provided Mollier diagram showing the refrigeration cycle when a buffer component is provided Sectional drawing of the fluid machine concerning 2nd Embodiment of this invention. The disassembled perspective view of the buffer structural member of the fluid machine shown in FIG. Sectional drawing of the fluid machine concerning 3rd Embodiment of this invention. The perspective view of the 2nd buffer structural member shown in FIG. Configuration diagram of a refrigeration cycle apparatus using the fluid machine shown in FIG. Sectional drawing of the fluid machine concerning 4th Embodiment of this invention. The perspective view of the buffer structural member of the fluid machine shown in FIG. Mollier diagram showing the refrigeration cycle of the refrigeration cycle apparatus shown in FIG. Sectional drawing of the fluid machine concerning 5th Embodiment of this invention. Sectional drawing of the fluid machine concerning 6th Embodiment of this invention. Configuration diagram of a refrigeration cycle apparatus in which a buffer is provided between an evaporator and a sub compression mechanism in a refrigerant circuit Mollier diagram showing the refrigeration cycle in the refrigeration cycle apparatus shown in FIG.

Explanation of symbols

1A, 1B, 1C Refrigeration cycle apparatus 2 Sub compression mechanism 3 Main compression mechanism 5 Power recovery mechanism 7 Power recovery unit 8 Electric motors 10A to 10F Fluid machine 11 Sealed container 12 Power recovery shaft 16 Oil reservoir 16a First oil reservoir 16b Second oil Pool 38 Main compressor shaft 43 Working chamber 46 Sub compression mechanism suction port 49 Sub compression mechanism discharge port 105, 107 Buffers 108, 108a, 108b, 109, 109a, 109b Branch buffer 112 Upstream buffer 113 Downstream buffer 235 , 245k, 246k, 248k, 250k Communication passages 232, 244, 247, 248, 260, 270 Buffer components

Claims (11)

An airtight container in which an oil reservoir in which oil is stored is formed at the bottom;
A main compression mechanism that is disposed in the sealed container and is supplied with the oil stored in the oil reservoir, and compresses the working fluid;
In the sealed container, a rotary electric motor disposed above the oil reservoir;
A main compressor shaft connecting the main compression mechanism and the rotary electric motor so that the main compression mechanism is driven by the rotary electric motor;
(Ii) a power recovery mechanism that recovers power from the working fluid by performing a suction stroke for sucking the working fluid and a discharge stroke for discharging the sucked working fluid; and (ii) ) A sub-compression mechanism driven by the power recovery mechanism to compress the working fluid and discharge it to the main compression mechanism side; and (iii) the sub-compression mechanism is driven by the power recovered by the power recovery mechanism. And a power recovery shaft that connects the power recovery mechanism and the sub-compression mechanism, and a power recovery unit,
A suction path that is provided between the main compression mechanism and the power recovery unit and guides the working fluid to the suction port of the sub compression mechanism or a discharge path of the working fluid discharged from the discharge port of the sub compression mechanism. And a buffer that expands the cross-sectional area of the flow path of the working fluid more than the opening area of the suction port or the opening area of the discharge port,
With fluid machine. An airtight container in which an oil reservoir in which oil is stored is formed at the bottom;
A main compression mechanism that is disposed in the sealed container and is supplied with the oil stored in the oil reservoir, and compresses the working fluid;
In the sealed container, a rotary electric motor disposed above the oil reservoir;
A main compressor shaft connecting the main compression mechanism and the rotary electric motor so that the main compression mechanism is driven by the rotary electric motor;
(Ii) a power recovery mechanism that recovers power from the working fluid by performing a suction stroke for sucking the working fluid and a discharge stroke for discharging the sucked working fluid; and (ii) ) A sub-compression mechanism driven by the power recovery mechanism to compress the working fluid and discharge it to the main compression mechanism side; and (iii) the sub-compression mechanism is driven by the power recovered by the power recovery mechanism. And a power recovery shaft that connects the power recovery mechanism and the sub-compression mechanism, and a power recovery unit,
An upstream portion that forms a suction path for guiding the working fluid to the suction port of the sub-compression mechanism, extends a cross-sectional area of the flow path of the working fluid beyond the opening area of the suction port, and a discharge of the sub-compression mechanism A downstream portion that forms a discharge path for the working fluid discharged from the outlet and expands a cross-sectional area of the flow path of the working fluid beyond the opening area of the discharge port, the main compression mechanism, the power recovery unit, A buffer provided between
With fluid machine. The central axis of the main compressor shaft coincides with the central axis of the power recovery shaft,
3. The fluid machine according to claim 1, wherein the power recovery unit is disposed in the oil reservoir in a posture in which the sub compression mechanism is positioned between the buffer and the power recovery mechanism. A buffer component having the buffer as an internal space is provided adjacent to the power recovery unit,
The buffer component member partitions the oil reservoir into a first oil reservoir located on the main compression mechanism side and a second oil reservoir located on the power recovery unit side,
The fluid machine according to any one of claims 1 to 3, further comprising a communication passage that allows the oil to pass between the first oil reservoir and the second oil reservoir.   The fluid machine according to claim 4, wherein the communication passage is configured by an oil leveling pipe that penetrates the buffer component member in an axial direction of the power recovery shaft or a groove formed in an outer peripheral portion of the buffer component member.   A branch buffer connected to the buffer so as to be filled with a working fluid to flow through the buffer, and extending in an oil surface direction along an inner peripheral surface of the sealed container to surround the oil reservoir in the circumferential direction; The fluid machine according to any one of claims 1 to 5. A buffer component having the buffer and the branch buffer as an internal space is provided adjacent to the power recovery unit,
The buffer constituent member partitions the oil reservoir into a first oil reservoir located on the main compression mechanism side and a second oil reservoir located on the power recovery unit side,
The fluid machine according to claim 6, wherein the first oil sump is surrounded by the branch buffer.   It is connected to the buffer so that it can be filled with the working fluid that should flow through the buffer, extends in the direction of the bottom along the inner peripheral surface of the sealed container, and the oil reservoir around the power recovery unit in the circumferential direction The fluid machine according to claim 1, further comprising an enclosing branch buffer. A buffer component having an internal space as the buffer and a bearing portion that supports the power recovery shaft is provided adjacent to the power recovery unit,
The internal space of the buffer component is partitioned so that an upstream buffer as the upstream portion is formed on one side with the bearing portion as a boundary, and a downstream buffer as the downstream portion is formed on the other side. The fluid machine according to claim 8.   The heat conductivity of the material which comprises the said buffer structural member is larger than the heat conductivity of the material which comprises the said airtight container and / or the said power recovery unit, The claim 7, Claim 9 or Claim 9 Fluid machinery.   A refrigeration cycle apparatus comprising the fluid machine according to any one of claims 1 to 10.

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