JP2006105564A - Fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the cooling capability or heating capability of a vapor compressing type refrigerating cycle using a fluid machine by preventing a thermal loss caused between discharged refrigerant of a compression mechanism and expanded refrigerant of an expansion mechanism in the fluid machine. <P>SOLUTION: This fluid machine comprises a partition part 90 partitioning the internal space of a casing 31 to a first and a second spaces. The first space 101 constituting a low-pressure space to be filled with the sucked refrigerant of the compression mechanism 90, and the second space 102 constitutes a high-pressure space to be filled with the discharged refrigerant of the compression mechanism 90. The expansion mechanism 70 is arranged in the first space, and the compression mechanism 50 is arranged in the second space 102. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fluid machine in which an expansion mechanism and a compression mechanism are housed in a sealed casing and perform an expansion stroke and a compression stroke of a vapor compression refrigeration cycle.

  Conventionally, a fluid machine in which a compression mechanism and an expansion mechanism are mechanically connected is known. This fluid machine is used for an expansion stroke and a compression stroke of a vapor compression refrigeration cycle performed in a refrigerant circuit such as an air conditioner.

  For example, in an air conditioner disclosed in Patent Document 1, a refrigerant circuit is configured by sequentially connecting a compression mechanism of a fluid machine, a radiator, an expansion mechanism of the fluid machine, and an evaporator in a closed circuit. In the refrigerant circuit, carbon dioxide as a refrigerant is circulated to perform a vapor compression refrigeration cycle.

Here, at the time of heating of the air conditioner, for example, the refrigerant is compressed by the compression mechanism, becomes a high temperature and high pressure higher than the critical pressure, and flows through the radiator. In the radiator, the refrigerant radiates heat to the room air and is cooled, while the room air is heated to perform heating. The refrigerant dissipated by the radiator is expanded by the expansion mechanism to become a low-pressure refrigerant and flows through the evaporator. In the evaporator, the refrigerant absorbs heat from the outdoor air and evaporates. As described above, this fluid machine simultaneously performs the expansion of the refrigerant by the expansion mechanism, that is, the expansion stroke of the refrigeration cycle, and the compression of the refrigerant by the compression mechanism, that is, the compression stroke of the refrigeration cycle. The fluid machine collects the expansion power of the refrigerant expanded by the expansion mechanism, that is, recovers the internal energy of the expanded refrigerant and uses it as a drive source for the compression mechanism.
JP 2001-153077 A

  By the way, in the fluid machine disclosed in Patent Document 1, an expansion mechanism that expands the refrigerant and a compression mechanism that compresses the refrigerant are housed in one sealed casing. The fluid machine is a so-called high-pressure dome type fluid machine in which a high-temperature and high-pressure refrigerant compressed by a compression mechanism is once discharged into the casing and then discharged to the outside of the casing. For this reason, the periphery of the expansion mechanism is a discharge refrigerant atmosphere of the compression mechanism. Therefore, the refrigerant expanded to the expansion mechanism by the discharge refrigerant of the compression mechanism (hereinafter referred to as expansion refrigerant) is heated, and at the same time, the discharge refrigerant of the compression mechanism is cooled by the expansion refrigerant of the expansion mechanism. there were. Here, when the refrigerant discharged from the compression mechanism is cooled, for example, when the air conditioner is heated as described above, the heating capability of the radiator is reduced. On the other hand, when the expansion refrigerant of the expansion mechanism is heated, for example, when the air conditioner is cooled, the cooling capacity of the evaporator is reduced. That is, in this fluid machine, the cooling capacity and the heating capacity obtained by the vapor compression refrigeration cycle are reduced due to heat exchange between the discharge refrigerant of the compression mechanism and the expansion refrigerant of the expansion mechanism in the casing. There was a problem.

  The present invention has been made in view of such problems, and an object of the present invention is to reduce the heat loss that occurs between the refrigerant discharged from the compression mechanism and the expansion refrigerant of the expansion mechanism. It is intended to improve the cooling capacity and heating capacity of the vapor compression refrigeration cycle.

  In the present invention, the internal space of the sealed casing is divided into a low pressure space and a high pressure space, and an expansion mechanism is disposed in the low pressure space, while a compression mechanism is disposed in the high pressure space.

  More specifically, in the first invention, the expansion mechanism (70) for expanding the refrigerant and the compression mechanism (50) for compressing the refrigerant are connected and stored in the sealed casing (31), and vapor compression is performed. It is premised on a fluid machine that performs an expansion stroke and a compression stroke of a refrigeration cycle. In this fluid machine, the inside of the casing (31) is divided into a first space (101) in which the expansion mechanism (70) is arranged and a second space (102) in which the compression mechanism (50) is arranged. The first space (101) includes a partition part (90) for partitioning, and the first space (101) communicates with the suction side of the compression mechanism (50) via the introduction pipe (35) to form a low-pressure space, while the second space (102) communicates with the discharge side of the compression mechanism (50) to form a high-pressure space.

  In the first invention, the compression mechanism (50) performs the compression stroke of the vapor compression refrigeration cycle, while the expansion mechanism (70) performs the expansion stroke of the vapor compression refrigeration cycle. Here, for example, the refrigerant evaporated in the evaporator flows into the first space (101) from the predetermined pipe, flows through the introduction pipe (35), and then is sucked into the compression mechanism (50) and compressed. That is, the first space (101) in which the expansion mechanism (70) is disposed is filled with the refrigerant sucked by the compression mechanism (50). On the other hand, the refrigerant compressed by the compression mechanism (50) is discharged into the second space (102). That is, the second space (102) in which the compression mechanism (50) is disposed is filled with the refrigerant discharged from the compression mechanism (50). Therefore, unlike the conventional fluid machine, it can be avoided that the expansion mechanism is heated by the refrigerant discharged from the compression mechanism and heat loss occurs between the refrigerant discharged from the compression mechanism and the expansion refrigerant of the expansion mechanism.

  In a general vapor compression refrigeration cycle, the refrigerant sucked by the compression mechanism (50) is cooler than the refrigerant sucked by the expansion mechanism (70) and the expansion refrigerant. Therefore, the suction and expansion refrigerant in the expansion mechanism (70) exchanges heat with the suction refrigerant in the compression mechanism (50) in the first space (101), and at the same time the suction and expansion refrigerant is cooled, the compression mechanism ( 50) The suction refrigerant is heated. For this reason, after the expansion stroke by the expansion mechanism (70), for example, the temperature of the refrigerant supplied to the evaporator that cools the room can be lowered, and the cooling capacity of the evaporator can be improved. Moreover, after the compression process in the compression mechanism (50), for example, the temperature of the refrigerant supplied to the radiator that heats the room can be increased, and the heating capacity of the radiator can be improved.

  According to a second aspect of the present invention, in the fluid machine according to the first aspect, the oil in the refrigerant stored in the casing (31) flows in and is supplied to the compression mechanism (50) and the expansion mechanism (70). 49), and the oil inflow portion (91) of the oil supply passage (49) is disposed in the high-pressure space.

  In the second aspect of the invention, when oil (refrigeration oil) contained in the refrigerant is stored in the casing (31), the oil is sucked into the oil supply passage (49) from the oil inflow portion (91). And after this oil distribute | circulates the predetermined supply channel | path (49), a compression mechanism (50) and an expansion mechanism (70) are lubricated by being supplied to a compression mechanism (50) and an expansion mechanism (70). .

  Here, in this invention, the said oil inflow part (91) is arrange | positioned in the 2nd space (102) used as a high voltage | pressure space. For this reason, the oil stored in the casing (31) can be efficiently pumped to the oil inflow portion (91) using the pressure of the high-pressure refrigerant.

  Further, for example, if an oil inflow portion is disposed in the low pressure space and the oil stored in the low pressure space is sucked from the oil inflow portion, the refrigerant stored in the low pressure space is likely to evaporate. So-called homing, in which bubbles are generated, can occur. As a result, there is a possibility that the oil can not be properly sucked by the oil inflow portion.

  On the other hand, in the present invention, since the oil inflow portion (91) is disposed in the high-pressure space (102), the above-described homing hardly occurs, and the oil inflow by the oil inflow portion (91) can be suitably performed.

  According to a third invention, in the fluid machine of the first or second invention, the low-pressure space (101) also serves as a gas-liquid separator that separates the refrigerant sucked into the compression mechanism (50) into liquid refrigerant and gas refrigerant. The refrigerant suction port (35a) of the introduction pipe (35) is opened to face the gas refrigerant separated in the low-pressure space (101).

  In the said 3rd invention, the suction | inhalation refrigerant | coolant of the compression mechanism (50) with which the 1st space (101) used as low pressure space is satisfy | filled is isolate | separated into a liquid refrigerant and a gas refrigerant. That is, the low-pressure space (101) is used as a gas-liquid separator that separates the gas-liquid two-phase refrigerant into liquid refrigerant and gas refrigerant.

  The gas refrigerant separated in the low pressure space (101) is actively sucked from the refrigerant suction port (35a) of the introduction pipe (35), passes through the introduction pipe (35), and is then compressed by the compression mechanism (50). Is done. On the other hand, the liquid refrigerant separated in the low pressure space (101) is stored in the low pressure space (101), gradually evaporates while maintaining a gas-liquid equilibrium relationship with the gas refrigerant, and is sucked into the introduction pipe (35).

  In a fluid machine according to a fourth aspect, in the fluid machine according to the third aspect, in the introduction pipe (35), the oil return that sends the oil stored at the bottom of the low pressure space (101) together with the gas refrigerant to the suction side of the compression mechanism (50) A passage (35b) is provided.

  In the fourth aspect of the invention, the oil stored in the low pressure space (101) is sucked into the introduction pipe (35) from the oil return passage (35b). The oil sucked into the introduction pipe (35) is sent to the suction side of the compression mechanism (50) together with the gas refrigerant separated in the low pressure space (101).

  According to a fifth invention, in the fluid machine according to any one of the first to fourth inventions, a heat insulating material (93) having a thermal conductivity smaller than that of a material constituting the expansion mechanism (70) is provided in the partition (90). ) Is provided.

  In the said 5th invention, a heat insulating material (93) is provided in the partition part (90) which divides the internal space of a casing (31) into the low voltage | pressure space (101) and the high voltage | pressure space (102). For this reason, it can suppress that the heat | fever of the high pressure space (102) filled with the discharge refrigerant | coolant is transferred to the expansion mechanism (70) side along a partition part (90).

  In the sixth invention, fins (95) are provided on the outer surface of the expansion mechanism (70).

  In the sixth invention, heat exchange between the low-pressure refrigerant around the expansion mechanism (70) and the expansion refrigerant in the expansion mechanism (70) is promoted by the fins (95). For this reason, the expansion refrigerant of the expansion mechanism (70) can be cooled to a lower temperature by the intake refrigerant of the compression mechanism (50). In other words, the intake refrigerant of the compression mechanism (50) is sucked into the expansion mechanism (70). The refrigerant can be heated to a higher temperature.

  According to a seventh invention, in the fluid mechanism according to any one of the second to sixth inventions, in the casing (31), the oil inflow portion (91), the compression mechanism (50), and An expansion mechanism (70) is arranged.

  In the seventh aspect, the high pressure space (102) is formed near the bottom of the casing (31), and the low pressure space (101) is formed near the top. Specifically, an oil inflow portion (91) is provided near the bottom of the high pressure space (102), and a compression mechanism (50) is provided above the oil inflow portion (91). Furthermore, a low-pressure space (101) is formed above the compression mechanism (50) with the partition (90) interposed therebetween, and an expansion mechanism (70) is provided in the low-pressure space (101).

  The eighth invention is the fluid machine according to any one of the second to sixth inventions, wherein in the casing (31), the expansion mechanism (70), the oil inflow portion (91), and A compression mechanism (50) is arranged.

  In the eighth invention, contrary to the seventh invention, the low pressure space (101) is formed near the bottom of the casing (31), and the high pressure space (102) is formed near the top. Specifically, an expansion mechanism (70) is provided near the bottom of the low-pressure space (101), and a high-pressure space (102) is formed above the expansion mechanism (70) with the partition (90) interposed therebetween. . An oil inflow portion (91) is provided near the bottom of the high pressure space (101), and a compression mechanism (50) is provided above the oil inflow portion (91).

  According to a ninth aspect of the present invention, in any one of the first to eighth fluid machines, an electric motor (40) that drives the compression mechanism (50) is disposed in the high-pressure space (102).

  In the ninth aspect of the invention, the electric motor (40) serving as the drive source for the compression mechanism (50) is disposed in the high-pressure space (102). For this reason, the electric motor (40) and the expansion mechanism (70) are partitioned by the partition portion (90). Therefore, it can suppress that the heat at the time of starting of an electric motor (40) moves to an expansion mechanism (70).

  A tenth aspect of the invention is the fluid machine according to any one of the first to ninth aspects of the invention, which performs an expansion stroke and a compression stroke of a vapor compression refrigeration cycle using carbon dioxide as a refrigerant.

  In the tenth aspect of the invention, the fluid machine of the first to ninth aspects of the invention is used for an expansion stroke and a compression stroke that perform a so-called supercritical cycle using carbon dioxide as a refrigerant. Here, generally, in the supercritical cycle, the discharge refrigerant temperature of the compression mechanism (50) is relatively high, so in a conventional fluid machine, the heat loss between the discharge refrigerant of the compression mechanism and the expansion refrigerant of the expansion mechanism Tends to increase. On the other hand, in the present invention, since the atmosphere around the expansion mechanism (70) is an intake refrigerant atmosphere, such heat loss can be effectively eliminated.

  According to the first aspect of the invention, the compression mechanism (50) is disposed in the second space (102) that is a high-pressure space filled with the refrigerant discharged from the compression mechanism (50), while the suction refrigerant of the compression mechanism (50) The expansion mechanism (70) is disposed in the first space (101), which is a low-pressure space filled with. For this reason, heat loss occurs between the refrigerant discharged from the compression mechanism (50) and the refrigerant expanded from the expansion mechanism (70). As a result, the cooling capacity and heating capacity of the vapor compression refrigeration cycle in which this fluid machine is used Can be avoided.

  Further, according to the present invention, the expansion refrigerant of the expansion mechanism (70) can be cooled by the surrounding intake refrigerant, while the intake refrigerant of the compression mechanism (50) can be heated. For this reason, after expanding by the expansion mechanism (70), for example, the temperature of the refrigerant flowing through the indoor heat exchanger serving as an evaporator can be lowered, and the cooling capacity of the evaporator can be improved. In addition, after being compressed by the compression mechanism (50), for example, the temperature of the refrigerant flowing through the indoor heat exchanger serving as a radiator can be increased, and the heating capacity of the radiator can be improved.

  According to the second aspect of the invention, in the oil supply passage (49) for supplying the oil in the refrigerant to the compression mechanism (50) and the expansion mechanism (70), the oil inflow portion (91) is placed in the high-pressure space (102 ). For this reason, the oil stored in the casing (31) can be efficiently sucked into the oil inflow portion (91) using the pressure of the high-pressure refrigerant. Further, in the high-pressure space (102), the above-described homing is unlikely to occur, and therefore the oil can be preferably sucked by the oil inflow portion (91). Therefore, oil lubrication in the compression mechanism (50) and the expansion mechanism (70) can be suitably performed.

  According to the third aspect of the present invention, the refrigerant before being sucked into the compression mechanism (50) can be gas-liquid separated in the first space (101) which is a low pressure space. The gas refrigerant separated in the first space (101) is actively sent to the compression mechanism (50). For this reason, liquid compression in the compression mechanism (50) can be avoided without providing a gas-liquid separator such as an accumulator separately from the fluid machine.

  According to the fourth aspect of the invention, the oil stored in the first space (101) is sucked into the introduction pipe (35) through the oil return passage (35b), and the oil is returned to the compression mechanism (50). it can. Therefore, it is possible to easily solve the problem that the lubricating oil in the compression mechanism (50) and the expansion mechanism (70) becomes insufficient while the oil is excessively stored in the bottom portion of the first space (101).

  According to the fifth aspect of the present invention, the heat transfer between the low pressure space (101) and the high pressure space (102) can be prevented as much as possible by providing the partition member (90) with the heat insulating material (93). . For this reason, for example, the heat of the refrigerant discharged from the high-pressure space (102) is transmitted to the low-pressure space (101), and as a result, the expansion mechanism (70) can be effectively prevented from being heated. That is, the heat loss between the refrigerant discharged from the compression mechanism (50) and the suction and expansion refrigerant of the expansion mechanism (70) can be more effectively eliminated.

  According to the sixth aspect of the invention, by providing the expansion mechanism (70) with the fin (95), the efficiency of heat exchange between the expansion mechanism (70) and the suction refrigerant around the expansion mechanism (70) is improved. be able to. For this reason, the expansion refrigerant | coolant of an expansion mechanism (70) can be cooled effectively, and the suction | inhalation refrigerant | coolant of a compression mechanism (50) can be heated effectively simultaneously. Therefore, the cooling capacity and heating capacity of the vapor compression refrigeration cycle in which this fluid machine is used can be further improved.

  According to the seventh aspect, in the internal space of the casing (31), the oil inflow portion (91) is disposed closest to the bottom portion, and the compression mechanism (50) and the expansion mechanism (70) are disposed on the upper portion thereof. Yes. For this reason, the oil stored in the bottom of the casing (31) is sucked from the oil inflow part (91), and this oil is sent to the upper part to facilitate oil supply to the compression mechanism (50) and the expansion mechanism (70). Can be done.

  According to the eighth aspect of the invention, in the internal space of the casing (31), the first space (101) serving as the low pressure space is formed near the bottom, and the second space (102) serving as the high pressure space is formed near the top. is doing. If it does in this way, it will become difficult to transmit the heat | fever of the hot discharge refrigerant | coolant in 2nd space (102) to the 1st space (101) located in the lower side. For this reason, the cooling effect of the expansion mechanism (70) and the expanded refrigerant in the first space (101) can be enhanced, and the cooling capacity and heating capacity of the vapor compression refrigeration cycle in which this fluid machine is used can be further improved. .

  According to the ninth aspect of the present invention, the electric motor (40) serving as the drive source of the compression mechanism (50) is disposed in the second space (102) serving as the high-pressure space, so that the heat generated when the electric motor (40) is started up. The transmission to the expansion mechanism (70) is suppressed as much as possible. For this reason, the cooling effect of the expansion mechanism (70) and the expanded refrigerant in the first space (101) can be enhanced, and the cooling capacity and heating capacity of the vapor compression refrigeration cycle in which this fluid machine is used can be further improved. .

  According to the tenth aspect of the invention, this fluid machine can be used for the expansion stroke and the compression stroke in the supercritical cycle using carbon dioxide as the refrigerant. Here, when the supercritical cycle is performed using carbon dioxide as a refrigerant, it is possible to improve the heating ability of a radiator used particularly for heating. Further, when the expansion power by the fluid machine is recovered as a drive source of the compression mechanism (50), the expansion power increases, so that the recovery power obtained by the fluid machine can also be increased.

  On the other hand, if the refrigerant is carbon dioxide, heat loss tends to occur between the discharge refrigerant of the compression mechanism (50) and the expansion refrigerant of the expansion mechanism (70). In the present invention, this heat loss is effective. Therefore, the cooling capacity and heating capacity in the refrigeration cycle using carbon dioxide can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
First, the fluid machine according to Embodiment 1 of the present invention will be described. This fluid machine is connected to a refrigerant circuit (20) of an air conditioner (10), and performs an expansion stroke and a compression stroke of a vapor compression refrigeration cycle in the refrigerant circuit (20).

<Overall configuration of air conditioner>
As shown in FIG. 1, the air conditioner (10) is a so-called separate type air conditioner in which an outdoor unit (11) arranged outdoors and an indoor unit (13) arranged indoors are individually provided. . The outdoor unit (11) includes an outdoor fan (12), an outdoor heat exchanger (23), a first four-way switching valve (21), a second four-way switching valve (22), and a compression / expansion unit (fluid machine). (30) is stored. On the other hand, the indoor unit (13) houses an indoor fan (14) and an indoor heat exchanger (24). The outdoor unit (11) and the indoor unit (13) are connected to each other by a pair of connecting pipes (15, 16).

  The refrigerant circuit (20) includes the above-described compression / expansion unit (30), the first and second four-way switching valves (21, 22), the indoor heat exchanger (24), and the outdoor heat exchanger (23). Are connected to form a closed circuit. The refrigerant circuit (20) is filled with carbon dioxide. In the refrigerant circuit (20), carbon dioxide as a refrigerant circulates to perform a vapor compression refrigeration cycle.

  Both the outdoor heat exchanger (23) and the indoor heat exchanger (24) are constituted by cross fin type fin-and-tube heat exchangers. In the outdoor heat exchanger (23), the refrigerant circulating in the refrigerant circuit (20) exchanges heat with the outdoor air taken in by the outdoor fan (12). In the indoor heat exchanger (24), the refrigerant circulating in the refrigerant circuit (20) exchanges heat with the air taken in by the indoor fan (14).

  The first four-way selector valve (21) has four ports. The first four-way selector valve (21) has a first port connected to the discharge port (37) of the compression / expansion unit (30) and a second port connected to the indoor heat exchanger (24) via the connecting pipe (15). The third port is connected to one end of the outdoor heat exchanger (23), and the fourth port is connected to the suction port (36) of the compression / expansion unit (30). The first four-way selector valve (21) has a state in which the first port and the second port communicate with each other and a state in which the third port and the fourth port communicate with each other (state indicated by a solid line in FIG. 1), The state is switched to a state in which the first port communicates with the third port and the second port communicates with the fourth port (a state indicated by a broken line in FIG. 1).

  The second four-way selector valve (22) has four ports. The second four-way switching valve (22) has a first port at the outflow port (39) of the compression / expansion unit (30), a second port at the other end of the outdoor heat exchanger (23), and a third port. The fourth port is connected to the inflow port (38) of the compression / expansion unit (30) on the other end of the indoor heat exchanger (24) via the communication pipe (16). The second four-way selector valve (22) includes a state in which the first port and the second port communicate with each other and a state in which the third port and the fourth port communicate with each other (state indicated by a solid line in FIG. 1), The state is switched to a state in which the first port communicates with the third port and the second port communicates with the fourth port (a state indicated by a broken line in FIG. 1).

<Configuration of compression / expansion unit>
As shown in FIG. 2, the compression / expansion unit (30) includes a casing (31) which is a vertically long and cylindrical sealed container. Inside the casing (31), a compression mechanism (50), an electric motor (40), and an expansion mechanism (70) are arranged in order from the bottom to the top.

  The electric motor (40) is disposed at an intermediate position in the vertical direction of the casing (31). The electric motor (40) includes a stator (41) and a rotor (42). The stator (41) is fixed to the inner peripheral wall of the casing (31). The rotor (42) is disposed inside the stator (42), and the main shaft portion (48) of the shaft (45) penetrates coaxially. The shaft (45) constitutes a rotating shaft that rotates while connecting the compression mechanism (50) and the expansion mechanism (70). Moreover, two expansion side eccentric parts (43, 44) are formed in the upper end part of a shaft (45), and two compression side eccentric parts (46, 47) are formed in the lower end part.

  The expansion side eccentric part (43, 44) is composed of a first expansion side eccentric part (43) located on the upper side and a second expansion side eccentric part (44) located on the lower side. Each expansion-side eccentric part (43, 44) is eccentric by a predetermined amount radially outward from the axis of the shaft (45). The compression side eccentric part (46, 47) is composed of a first compression side eccentric part (46) located on the upper side and a second compression side eccentric part (47) located on the lower side. Each of the compression side eccentric portions (46, 47) is eccentric by a predetermined amount radially outward from the axis of the shaft (45). The first and second compression side eccentric parts (46, 47) are fixed to the shaft (45) in a state where the phases are different from each other by 180 ° with respect to the axis of the shaft (45).

  The expansion mechanism (70) constitutes a so-called oscillating piston type rotary expander. The expansion mechanism (70) is a two-stage expander having two sets of fluid chambers (72, 82) and two sets of pistons (73, 83) corresponding to the respective fluid chambers (72, 82). It is. The expansion mechanism (70) includes a rear head (76), a first cylinder (71), an intermediate plate (77), a second cylinder (81), and a front head (78) stacked in order from top to bottom. Yes.

  The first and second cylinders (71, 81) are each formed in an annular shape. The space inside the first cylinder (71) is closed by the rear head (76) and the intermediate plate (77) to constitute the first fluid chamber (72). Further, the space inside the second cylinder (81) is closed by the intermediate plate (77) and the front head (78) to constitute the second fluid chamber (82).

  As shown in FIG. 3, annular pistons (73, 83) are arranged in the respective expansion chambers (72, 82). Each piston (73, 83) is provided with a plate-like blade (74, 84). Each blade (74, 84) is held in a blade groove of each cylinder (71, 72) via a pair of swing bushes (75, 85).

  The first piston (73) disposed in the first fluid chamber (72) is engaged with the first expansion side eccentric portion (43) of the shaft (45). The second piston (83) disposed in the second fluid chamber (82) is engaged with the second expansion side eccentric portion (44) of the shaft (45). Each piston (73, 83) has an inner peripheral surface in sliding contact with an outer peripheral surface of each expansion side eccentric portion (43, 44), and an outer peripheral surface in sliding contact with an inner peripheral surface of the cylinder (71, 81). Each piston (73,83) rotates along the expansion side eccentric portion (43,44) and rotates along the inner peripheral surface of each cylinder (71,81) as the shaft (45) rotates. Revolve.

  As shown in FIG. 2, the expansion mechanism (70) is provided with the inflow port (38) and the outflow port (39). The inflow port (38) is formed in the front head (78), and the outflow end opens on the upper surface of the second fluid chamber (82). The inflow port (38) passes through the casing (31), and the inflow end thereof is connected to piping outside the casing (31). The outflow port (39) is formed in the first cylinder (71), and the inflow end opens on the inner peripheral surface of the first cylinder (71). The outflow port (39) passes through the casing (31), and the outflow end thereof is connected to piping outside the casing (31).

  The expansion mechanism (70) is provided with a communication path (80) shown in FIG. The communication passage (80) is formed through the intermediate plate (77), and constitutes an introduction passage for guiding the refrigerant sucked into the second fluid chamber (82) to the first fluid chamber (72). Yes.

  The expansion mechanism (70) as described above expands the refrigerant as the fluid chambers (72, 82) expand and contract with the revolution movement of the pistons (73, 83). Specifically, when the inflow port (38) and the second fluid chamber (82) communicate with the revolution of the second piston (83), the refrigerant is sucked into the second fluid chamber (82) from the inflow port (38). Is done. Thereafter, when the second piston (83) revolves further, the second fluid chamber (82) filled with the refrigerant communicates with the inflow end of the communication passage (80). As a result, the refrigerant flows through the communication path (80) and is introduced into the first fluid chamber (72). When the volume of the first fluid chamber (72) filled with the refrigerant is increased with the revolution of the first piston (73), the refrigerant is expanded. Thereafter, when the first piston (73) revolves further, the first fluid chamber (72) filled with the refrigerant communicates with the outflow port (39). As a result, the refrigerant that has been expanded to a low pressure flows through the outflow port (39) and is discharged to the outside of the expansion mechanism (70).

  As shown in FIG. 2, the compression mechanism (50) is a so-called oscillating piston type rotary compressor. The compression mechanism (50) is a two-stage compressor having two sets of compression chambers (52, 62) and two sets of pistons (53, 63) corresponding to the compression chambers (52, 62). It is. In this compression mechanism (50), a rear head (56), a first cylinder (51), an intermediate plate (57), a second cylinder (61), and a front head (58) are laminated in order from top to bottom. Yes.

  The first and second cylinders (51, 61) are each formed in an annular shape. The space inside the first cylinder (51) is closed by the rear head (56) and the intermediate plate (57) to form the first compression chamber (52). Further, the space inside the second cylinder (61) is closed by the intermediate plate (57) and the front head (58) to constitute the second compression chamber (62).

  In each compression chamber (52, 62), an annular piston (53, 63) is arranged. Each piston (53, 63) is provided with a not-shown plate-like blade. Each blade is held in a blade groove of each cylinder (51, 61) via a pair of swing bushes. The first and second compression chambers (52, 62) are partitioned into a low pressure side space and a high pressure side space by the piston (53, 63) and each blade.

  The first piston (53) disposed in the first cylinder (51) is engaged with the first compression side eccentric portion (46) of the shaft (45). The second piston (63) disposed in the second cylinder (61) is engaged with the second compression side eccentric portion (47) of the shaft (45). As for each piston (53,63), an inner peripheral surface is slidably contacted with the outer peripheral surface of each expansion side eccentric part (46,47), and an outer peripheral surface is slidably contacted with the inner peripheral surface of a cylinder (51,61). Each piston (53, 63) rotates along the compression side eccentric portion (46, 47) and rotates along the inner peripheral surface of each cylinder (51, 61) as the shaft (45) rotates. Revolve. The compression of the refrigerant by the compression mechanism (50) is performed by expanding and contracting the volume of the low pressure side and the high pressure side of each compression chamber (52, 62) by the revolution of the piston (53, 63).

  The compression mechanism (50) is provided with suction ports (54, 64) corresponding to the respective compression chambers (52, 62). These suction ports (54, 64) are composed of a first suction port (54) formed in the first cylinder (51) and a second suction port (64) formed in the second cylinder (61). Has been. The first suction port (54) communicates with the low pressure side of the first compression chamber (52). The second suction port (64) communicates with the low pressure side of the second compression chamber (62). That is, the first and second suction ports (54, 64) constitute introduction ports for sucking low-pressure refrigerant into the compression chambers (52, 62).

  Further, the compression mechanism (50) is formed with discharge ports (55, 65) corresponding to the respective compression chambers (52, 62). These discharge ports (55, 65) include a first discharge port (55) formed at the upper end of the rear head (56) and a second discharge port (65) formed at the lower end of the front head (58). It consists of and. The first discharge port (55) communicates with the high pressure side of the first compression chamber (52) via a passage (not shown). The second discharge port (65) communicates with the k high pressure side of the second compression chamber (62) via a passage (not shown). That is, each discharge port (55, 65) constitutes a discharge port for discharging the refrigerant compressed in each compression chamber (52, 62) to the outside of the compression mechanism (50). These discharge ports (55, 65) are each provided with a discharge valve (not shown). The rear head (56) is formed with a through hole (59) for sending the discharged refrigerant discharged from the second discharge port (65) to the upper part of the rear head (56).

  As a feature of the present invention, the compression / expansion unit (30) includes a partition (90) that partitions the space inside the casing (31) into two spaces. The partition portion (90) also serves as the front head (78) of the expansion mechanism (70) described above. In other words, the outer peripheral surface of the front head (78) and the inner peripheral surface of the casing (31) are almost in contact with each other, so that the space inside the casing (31) is the first space (101) formed closer to the upper part. And a second space (102) formed from the middle part to the lower part.

  One end of an introduction pipe (35) is connected to the first space (101). A part of the introduction pipe (35) extends in the vertical direction along the outside of the casing (31), and the upper and lower ends thereof are inserted and held in the casing (31), respectively. The introduction pipe (35) located in the first space (101) is bent along the outer periphery of the expansion mechanism (70), and its opening end faces upward so that the refrigerant suction port (35a) is opened. It is composed. The refrigerant suction port (35a) is located at substantially the same height as the upper end surface of the rear head (76) of the expansion mechanism (70). On the other hand, the other end of the introduction pipe (35) is branched into two and connected to the suction ports (54, 64) of the compression mechanism (50). In this way, the first space (101) communicates with the suction side (low pressure side) of the compression mechanism (50) via the introduction pipe (35), and constitutes a low pressure space.

  The suction port (36) described above is connected to the first space (101). The suction port (36) passes through the top end of the casing (31) and is inserted into the first space (101), and the opening is located on the upper extension of the shaft (45).

  As described above, the first space (101) is filled with the low-pressure refrigerant serving as the suction refrigerant of the compression mechanism (50). Therefore, in the first space (101), the suction and expansion refrigerant of the expansion mechanism (70) cools by the heat exchange between the suction and expansion refrigerant of the expansion mechanism (70) and the suction refrigerant of the compression mechanism (50). Is done.

  The first space (101) also serves as a gas-liquid separator that separates the refrigerant introduced from the suction port (36) into liquid refrigerant and gas refrigerant. That is, of the gas-liquid two-phase refrigerant flowing into the first space (101) from the suction port (36), the liquid refrigerant is placed on the upper surface side of the front head (78), which is the bottom of the first space (101). The gas refrigerant is stored above the expansion mechanism (70) in the first space (101). The introduction pipe (35) actively takes in the gas refrigerant stored in the upper portion of the first space (101) from the refrigerant suction port (35a) and guides it to the suction side of the compression mechanism (50).

  Further, the introduction pipe (35) has an oil return opening (oil return passage) through which oil (refrigeration oil) contained in the liquid refrigerant stored at the bottom of the first space (101) is sent to the suction side of the compression mechanism (50). ) (35b) is formed. The oil return opening (35b) is formed in the vicinity of the bent portion of the introduction pipe (35) at a position relatively close to the partition portion (90). The refrigerating machine oil flows into the introduction pipe (35) through the oil return opening (35b) and is sent to the suction side of the compression mechanism (50) together with the gas refrigerant flowing in from the refrigerant suction port (35a).

  The second space (102) communicates with the discharge side (high pressure side) of the compression mechanism (50) via the first and second discharge ports (55, 56) described above, and constitutes a high pressure space. Yes. The discharge port (37) described above is connected to the second space (102). The discharge port (37) is inserted at a height position near the lower side of the partition portion (90) in the body portion of the casing (31).

  In the second space (102), the refrigerating machine oil in the refrigerant stored at the bottom of the second space (102) is transferred to the compression mechanism (50) and the expansion mechanism (70) via the oil supply passage (49). An oil pump (91) which is an oil inflow portion for supplying is provided.

  The oil pump (91) is connected to the lower end portion of the shaft (45), and is constituted by a so-called centrifugal pump that sucks oil using a centrifugal force generated by the rotation of the shaft (45). The oil supply passage (49) extends in the vertical direction from the lower end to the upper end of the shaft (45) as shown by the dotted line in FIG. The oil supply passage (49) is connected to the compression chambers (52, 62) of the compression mechanism (50) and the fluid chambers (72, 82) of the expansion mechanism (70) via a plurality of oil branch passages (not shown). ).

  Furthermore, a heat insulating material (93) and a support member (94) are provided below the front head (78), which is the partition portion (90) described above. The heat insulating material (93) is an annular member through which the shaft (45) passes, and is formed in a convex shape in which the upper half of the outer peripheral surface protrudes. The heat insulating material (93) is made of a material having a lower thermal conductivity than the material constituting the expansion mechanism (70), such as a resin material such as FRP (fiber reinforced plastic). The heat insulating material (93) suppresses heat transfer between the low pressure space (101) and the high pressure space (102).

  The support member (94) is a concave and annular member formed so as to be fitted to the outer periphery of the heat insulating material (93). The outer peripheral surface of the support member (94) is fixed to the inner peripheral surface of the casing (31). The support member (94) holds the heat insulating material (93) and the expansion mechanism (70) inside the casing (31). The support member (94) is a seal that suppresses fluid leakage between the low pressure space (101) and the high pressure space (102) by filling a gap between the front head (78) and the casing (31). It also serves as a mechanism.

-Operation-
Next, the operation of the air conditioner (10) will be described. Here, the operation during the cooling operation and the heating operation of the air conditioner (10) will be described with reference to FIG. 1 and FIG. FIG. 4 is a schematic configuration diagram showing a refrigerant flow in the compression / expansion unit (30).

<Cooling operation>
During the cooling operation, the first four-way switching valve (21) and the second four-way switching valve (22) are switched to a state indicated by a broken line in FIG. In this state, when the electric motor (40) of the compression / expansion unit (30) is energized, the refrigerant circulates in the refrigerant circuit (20) to perform a vapor compression refrigeration cycle. During the cooling operation, the outdoor heat exchanger (23) serves as a radiator, while the indoor heat exchanger (24) serves as an evaporator.

  The high-temperature and high-pressure refrigerant compressed by the compression mechanism (50) of the compression / expansion unit (30) passes through the first and second discharge ports (55, 65) of FIG. 4 and is discharged into the second space (102). Is done. Thereafter, the high-temperature and high-pressure refrigerant in the second space (102) is discharged from the compression / expansion unit (30) through the discharge port (37).

  The refrigerant discharged from the compression / expansion unit (30) is sent to the outdoor heat exchanger (23) through the first four-way switching valve (21) shown in FIG. In the outdoor heat exchanger (23), the refrigerant flowing in is radiated to the outdoor air and cooled.

  The high-pressure refrigerant cooled in the outdoor heat exchanger (23) passes through the second four-way switching valve (22) and flows into the expansion mechanism (70) of the compression / expansion unit (30) from the inflow port (38). In this expansion mechanism (70), the high-pressure refrigerant expands, and its internal energy is converted into rotational power of the shaft (45) and transmitted to the compression mechanism (50). Thereby, the power load of an electric motor (40) is reduced. The expanded refrigerant flows out from the compression / expansion unit (30) through the outflow port (39), and is sent to the indoor heat exchanger (24) through the second four-way switching valve (22).

  In the indoor heat exchanger (24), the refrigerant that has flowed in absorbs heat from the room air and evaporates, thereby cooling the room air. The refrigerant evaporated in the indoor heat exchanger (24) passes through the first four-way switching valve (21) and passes from the suction port (36) shown in FIG. 4 to the first space (101) of the compression / expansion unit (30). Inhaled.

  In the first space (101), the low-temperature and low-pressure refrigerant sucked flows around the expansion mechanism (70), thereby cooling the expansion mechanism (70). Therefore, the suction and expansion refrigerant supplied from the expansion mechanism (70) to the indoor heat exchanger (24) is also cooled.

  In the first space (101), the gas-liquid two-phase refrigerant is separated into a gas refrigerant and a liquid refrigerant. Then, the gas refrigerant stored in the upper portion of the first space (101) is actively sucked into the introduction pipe (35) from the refrigerant suction port (35a). At the same time, the refrigeration oil stored in the bottom of the first space (101) is sucked from the oil return opening (35b) of the introduction pipe (35) and flows through the introduction pipe (35) together with the gas refrigerant. The gas refrigerant flowing through the introduction pipe (35) is branched, then sucked into the compression chambers (52, 62) of the compression mechanism (50), and compressed again in the compression chambers (52, 56).

<Heating operation>
During the heating operation, the first four-way switching valve (21) and the second four-way switching valve (22) are switched to the state shown by the solid line in FIG. When the electric motor (40) of the compression / expansion unit (30) is energized in this state, the refrigerant circulates in the refrigerant circuit (20), and a vapor compression refrigeration cycle is performed. During the heating operation, the indoor heat exchanger (24) serves as an evaporator, while the indoor heat exchanger (23) serves as a radiator.

  The high-temperature and high-pressure refrigerant compressed by the compression mechanism (50) of the compression / expansion unit (30) passes through the first and second discharge ports (55, 65) of FIG. 4 and is discharged into the second space (102). Is done. Thereafter, the high-temperature and high-pressure refrigerant in the second space (102) is discharged from the compression / expansion unit (30) through the discharge port (37).

  The refrigerant discharged from the compression / expansion unit (30) is sent to the indoor heat exchanger (24) through the first four-way switching valve (21) shown in FIG. In the indoor heat exchanger (24), the refrigerant that has flowed in dissipates heat to the indoor air and is cooled, thereby heating the indoor air.

  The high-pressure refrigerant cooled by the indoor heat exchanger (24) passes through the second four-way switching valve (22) and flows into the expansion mechanism (70) of the compression / expansion unit (30) from the inflow port (38). In this expansion mechanism (70), the high-pressure refrigerant expands, and its internal energy is converted into rotational power of the shaft (45) and transmitted to the compression mechanism (50). Thereby, the power load of an electric motor (40) is reduced. Then, the low-temperature and low-pressure refrigerant after expansion flows out of the compression / expansion unit (30) through the outflow port (39), and is sent to the outdoor heat exchanger (23) through the second four-way switching valve (22). It is done.

  In the outdoor heat exchanger (23), the refrigerant that has flowed in absorbs heat from the outdoor air and evaporates. The refrigerant evaporated in the outdoor heat exchanger (23) passes through the first four-way switching valve (21) and enters the first space (101) of the compression / expansion unit (30) from the suction port (36) shown in FIG. Inhaled.

  In the first space (101), the sucked refrigerant flows around the expansion mechanism (70), so that the heat of the expansion mechanism (70) is given to the low-temperature and low-pressure refrigerant. For this reason, the refrigerant compressed by the compression mechanism (50) and then supplied to the indoor heat exchanger (24) is heated in advance.

  In the first space (101), the gas-liquid two-phase refrigerant is separated into a gas refrigerant and a liquid refrigerant. Then, the gas refrigerant stored in the upper portion of the first space (101) is actively sucked into the introduction pipe (35) from the refrigerant suction port (35a). At the same time, the refrigeration oil stored in the bottom of the first space (101) is sucked from the oil return opening (35b) of the introduction pipe (35) and flows through the introduction pipe (35) together with the gas refrigerant.

  The gas refrigerant flowing through the introduction pipe (35) is branched, then sucked into the compression chambers (52, 62) of the compression mechanism (50), and compressed again in the compression chambers (52, 56).

-Effect of Embodiment 1-
According to the first embodiment, the following effects are exhibited.

  According to the embodiment, the interior of the casing (31) is partitioned by the partition (90), and the expansion mechanism (70) is disposed in the first space (101) that is the low pressure space, while the first pressure that is the high pressure space. The compression mechanism (50) is arranged in the two spaces (102). The intake refrigerant of the expansion mechanism (70) and the expansion refrigerant are cooled by the intake refrigerant of the compression mechanism (50), and at the same time, the intake refrigerant is heated. For this reason, during the cooling operation of the air conditioner (10), the temperature of the refrigerant flowing through the indoor heat exchanger (24) can be lowered, and the cooling capacity of the indoor heat exchanger (24) can be improved. In addition, during the heating operation of the air conditioner (10), the temperature of the refrigerant flowing through the indoor heat exchanger (24) can be increased, and the heating capacity of the indoor heat exchanger (24) can be improved.

  Here, as shown in FIG. 2, since the electric motor (40) that drives the compression mechanism (50) is arranged in the second space (102), which is a high-pressure space, heat generated when the electric motor (40) is started up is generated. Transmission to the first space (101) can be suppressed, and the suction of the expansion mechanism (70) and the cooling effect of the expanded refrigerant can be prevented from being impaired.

  Furthermore, since the heat insulating material (93) is provided in the partition part (90), heat transfer between the low pressure space (101) and the high pressure space (102) can be suppressed as much as possible, and the expansion mechanism (70) It is possible to more effectively prevent the suction effect and the cooling effect of the expanded refrigerant from being impaired.

  Moreover, according to the said embodiment, the oil pump (91) which is an oil inflow part of an oil supply channel | path (49) is arrange | positioned in the high voltage | pressure space (102). For this reason, the oil stored at the bottom of the casing (31) can be efficiently sucked from the oil pump (91) using the pressure of the high-pressure refrigerant. For this reason, this oil can be efficiently supplied to the compression mechanism (50) and the expansion mechanism (70), and the compression mechanism (50) and the expansion mechanism (70) can be effectively lubricated.

  Furthermore, according to the embodiment, in the first space (101), which is a low pressure space, the refrigerant before being sucked into the compression mechanism (50) can be separated into gas and liquid. The gas refrigerant separated in the first space (101) is actively sent to the compression mechanism (50). For this reason, liquid compression in the compression mechanism (50) can be avoided without providing a gas-liquid separator such as an accumulator separately from the compression / expansion unit (30).

<Modification of Embodiment 1>
Next, a modification of the first embodiment will be described. As shown in FIG. 5, this modification is different from the first embodiment in the configuration of the expansion mechanism (70).

  Specifically, the surface of the expansion mechanism (70) extends over the outer edges of the rear head (76), the first cylinder (71), the intermediate plate (77), the second cylinder (81), and the front head (78). Thus, a plurality of fins (95) are provided. The fin (95) is formed in a plate shape, for example.

  In this modification, the heat exchange rate between the suction refrigerant of the compression mechanism (50) and the expansion mechanism (70) in the first space (101) can be improved. For this reason, the suction and expansion refrigerant of the expansion mechanism (70) can be effectively cooled, and at the same time, the suction refrigerant of the compression mechanism (50) can be effectively heated. Therefore, compared with the said Embodiment 1, the further improvement of the cooling capability at the time of cooling operation or the heating capability at the time of heating operation can be aimed at.

<< Embodiment 2 of the Invention >>
Next, the configuration of the compression / expansion unit (30) according to Embodiment 2 will be described with reference to FIGS. The compression / expansion unit (30) of the second embodiment is different from the first embodiment in the arrangement of the compression mechanism (50), the expansion mechanism (70), and the electric motor (40) in the casing (31). Hereinafter, differences from the first embodiment will be described.

  As shown in FIG. 6, an expansion mechanism (70), a compression mechanism (50), and an electric motor (40) are arranged in the casing (31) in order from the bottom to the top. Further, the internal space of the casing (31) is divided into a first space (101) formed near the lower portion by a partition portion (90) shared by the rear head (76) of the expansion mechanism (70), and an upper portion from the middle portion. And is partitioned into a second space (102) formed across. In addition, a support member (94) and a heat insulating material (93) are provided on the upper portion of the partition portion (90) in an upside-down state with respect to the first embodiment.

  A suction port (36) is connected to the first space (101) and is filled with a low-pressure refrigerant that serves as a suction refrigerant of the compression mechanism (50). That is, the first space (101) constitutes a low pressure space. Therefore, in the first space (101), the suction and expansion refrigerant of the expansion mechanism (70) cools by the heat exchange between the suction and expansion refrigerant of the expansion mechanism (70) and the suction refrigerant of the compression mechanism (50). Is done. The first space (101) also serves as a gas-liquid separator that separates the refrigerant introduced from the suction port (36) into liquid refrigerant and gas refrigerant, as in the first embodiment. That is, among the gas-liquid two-phase refrigerant flowing into the first space (101) from the suction port (36), the liquid refrigerant is stored at the bottom of the first space (101), and the gas refrigerant is stored in the first space (101). In the vicinity of the periphery of the expansion mechanism (70).

  One end of the introduction pipe (35) is connected to the first space (101). The introduction pipe (35) is provided inside the casing (31) so as to penetrate the rear head (76), the support member (94), and the heat insulating material (93). One end of the introduction pipe (35) faces the bottom of the first space (101), while the other end branches into two and the first and second suction ports (54) of the compression mechanism (50). , 64). A circular refrigerant inlet (35a) is formed in the vicinity of the lower side of the partition (90) in the introduction pipe (35). Therefore, the gas refrigerant stored in the upper part of the first space (101) is sucked into the introduction pipe (35) from the refrigerant suction port (35a) and guided to the suction side of the compression mechanism (50). On the other hand, the opening end located at the lower end of the introduction pipe (35) constitutes an oil return opening (35b). For this reason, the refrigeration oil contained in the liquid refrigerant stored at the bottom of the first space (101) is sucked into the introduction pipe (35) from the oil return opening (35b) and sucked from the refrigerant suction port (35a). The gas refrigerant is sent to the compression mechanism (50). In the introduction pipe (35), an orifice (97) for providing a predetermined resistance to the flow of fluid sucked from the oil return opening (35b) is provided near the upper side of the oil return opening (35b). It has been. By providing the orifice (97) in this way, the liquid refrigerant stored in the first space (101) is prevented from being sucked from the oil return opening (35b), while stored in the first space (101). Only oil can be actively taken into the introduction pipe (35) through the oil return opening (35b).

  The second space (102) communicates with the first and second discharge ports (55, 56) of the compression mechanism (50) as in the first embodiment, and serves as a high-pressure refrigerant that is discharged from the compression mechanism (50). Filled with refrigerant. That is, the second space (102) constitutes a high-pressure space. The discharge port (37) connected to the second space (102) is inserted through the top end of the casing (31) to the second space (102).

  In the second embodiment, the shaft (45) is composed of two split shafts (45a, 45b). This split shaft (45a, 45b) is composed of a first split shaft (45a) that passes through the electric motor (40) and the compression mechanism (50), and a second split shaft (45b) that passes through the expansion mechanism (70). Has been. The divided shafts (45a, 45b) are connected to each other by a fitting member (96), so that both shafts (45a, 45b) constitute an integral shaft (45). The first split shaft (45a) is formed with a first oil supply passage (49a) extending in the vertical direction from the lower end to the height near the electric motor (40). The first oil supply passage (49a) communicates with the compression chambers (52, 62) of the compression mechanism (50) via an oil branch passage (not shown). On the other hand, the second divided shaft (45b) is formed with a second oil supply passage (49b) extending in the vertical direction from the upper end to the lower end. The second oil supply passage (49b) communicates with each fluid chamber (72, 82) of the expansion mechanism (70) via an oil branch passage (not shown).

  In addition, a slight gap is formed in the connecting portion of both shafts (45a, 45b), and this gap constitutes an oil inflow portion (91). That is, the refrigerating machine oil stored in the second space (102) is pumped to the high-pressure refrigerant and sucked from the oil inflow portion (91). The refrigerating machine oil sucked from the oil inflow portion (91) flows upward through the first oil supply passage (49a) formed in the first split shaft (45a) and is supplied to the compression mechanism (50). At the same time, the refrigerating machine oil sucked from the oil inflow portion (91) flows downward through the second oil supply passage (49b) formed in the second split shaft (45b) and is supplied to the expansion mechanism (70). .

-Effect of Embodiment 2-
According to the above-described embodiment, as in the first embodiment, the inside of the casing (31) is partitioned by the partition portion (90), and the expansion mechanism (70) is disposed in the first space (101) serving as the low-pressure space. The compression mechanism (50) is arranged in the second space (102) that is a high-pressure space. As shown in FIG. 7, the suction and expansion refrigerant of the expansion mechanism (70) is cooled by the suction refrigerant of the compression mechanism (50), and at the same time, the suction refrigerant is heated. For this reason, during the cooling operation of the air conditioner (10), the temperature of the refrigerant flowing through the indoor heat exchanger (24) can be lowered, and the cooling capacity of the indoor heat exchanger (24) can be improved. In addition, during the heating operation of the air conditioner (10), the temperature of the refrigerant flowing through the indoor heat exchanger (24) can be increased, and the heating capacity of the indoor heat exchanger (24) can be improved.

  In particular, according to the second embodiment, in the internal space of the casing (31), the high-pressure space (102) is formed on the upper side, and the low-pressure space (101) is formed on the lower side. If it does in this way, it will become difficult to transmit the heat | fever of the hot discharge refrigerant | coolant in 2nd space (102) to the 1st space (101) located in the lower side. For this reason, the cooling effect of the expansion mechanism (70) and the expanded refrigerant in the first space (101) is enhanced, and the cooling capacity and the heating capacity of the vapor compression refrigeration cycle in which the expansion / compression unit (30) is used are further improved. Can be planned.

  Moreover, according to the said Embodiment 2, a shaft (45) is comprised by the 1st and 2nd division | segmentation shaft (45a, 45b), and an oil inflow part (91) is provided in the clearance gap between both shafts (45a, 45b). Is configured. And this oil inflow part (91) is arrange | positioned in the 2nd space (102) used as a high voltage | pressure space. For this reason, the oil stored in the second space (102) can be efficiently pumped to the oil inflow portion (91) using the pressure of the high-pressure refrigerant. Then, the oil sucked from the oil inflow portion (91) is supplied to the compression mechanism (50) through the first oil supply passage (49a), and at the same time, the expansion mechanism (through the second oil supply passage (49b) ( 70) can be supplied. Therefore, the compression mechanism (50) and the expansion mechanism (70) can be effectively lubricated.

<< Other Embodiments >>
The present invention may be configured as follows with respect to the above embodiment.

  In the above embodiment, the compression mechanism (50) and the expansion mechanism (70) are configured as a swinging piston type. However, the compression mechanism (50) and the expansion mechanism (70) may be of any other type (for example, scroll type, rotary piston type).

  In the above embodiment, the electric motor (40) is provided integrally with the compression / expansion unit (30). However, the electric motor (40) may be provided separately from the compression / expansion unit (30).

  Furthermore, in the above embodiment, carbon dioxide is used as the refrigerant used in the vapor compression refrigeration cycle, but in addition to this, an HFC refrigerant, an HC refrigerant, or a natural refrigerant such as water or ammonia is used. The same effect can be obtained.

  As described above, the expansion mechanism and the compression mechanism are housed in a sealed casing, and the fluid machine that performs the expansion stroke and the compression stroke of the vapor compression refrigeration cycle is useful.

It is a refrigerant circuit figure of the air conditioner to which the fluid machine concerning an embodiment is applied. It is a longitudinal cross-sectional view which shows the whole structure of the fluid machine which concerns on Embodiment 1. FIG. 3 is a cross-sectional view of an expansion mechanism of the fluid machine according to Embodiment 1. FIG. FIG. 3 is a schematic configuration diagram illustrating a refrigerant flow in the fluid machine according to the first embodiment. It is a longitudinal cross-sectional view which shows the whole structure of the fluid machine which concerns on the modification of Embodiment 1. It is a longitudinal cross-sectional view which shows the whole structure of the fluid machine which concerns on Embodiment 2. FIG. FIG. 5 is a schematic configuration diagram illustrating a refrigerant flow in a fluid machine according to a second embodiment.

Explanation of symbols

(10) Air conditioner
(30) Compression / expansion unit (fluid machinery)
(31) Casing
(35) Introduction pipe
(35a) Refrigerant inlet
(35b) Oil return passage (oil return opening)
(40) Electric motor
(45) Shaft
(49) Oil supply passage
(50) Compression mechanism
(70) Expansion mechanism
(91) Oil inlet (oil pump)
(93) Insulation
(95) Fin
(101) First space (low pressure space)
(102) Second space (high pressure space)

Claims (10)

An expansion mechanism (70) for expanding the refrigerant and a compression mechanism (50) for compressing the refrigerant are connected and stored in the sealed casing (31), and the expansion stroke and the compression stroke of the vapor compression refrigeration cycle are stored. A fluid machine that performs
A partition (90) that divides the interior of the casing (31) into a first space (101) in which the expansion mechanism (70) is disposed and a second space (102) in which the compression mechanism (50) is disposed. With
The first space (101) communicates with the suction side of the compression mechanism (50) via the introduction pipe (35) to form a low-pressure space, while the second space (102) is the compression mechanism (50). Fluid machine that forms a high-pressure space in communication with the discharge side. The fluid machine according to claim 1,
An oil supply passage (49) through which oil in the refrigerant stored in the casing (31) flows and is supplied to the compression mechanism (50) and the expansion mechanism (70);
A fluid machine in which an oil inflow portion (91) of the oil supply passage (49) is disposed in a high-pressure space. The fluid machine according to claim 1 or 2,
The low-pressure space (101) also serves as a gas-liquid separator that separates the refrigerant sucked into the compression mechanism (50) into liquid refrigerant and gas refrigerant,
A fluid machine in which the refrigerant inlet (35a) of the introduction pipe (35) is opened so as to face the gas refrigerant separated in the low-pressure space (101). The fluid machine according to claim 3, wherein
The fluid machine in which the introduction pipe (35) is provided with an oil return passage (35b) for sending oil stored in the bottom of the low pressure space (101) together with a gas refrigerant to the suction side of the compression mechanism (50). The fluid machine according to any one of claims 1 to 4,
A fluid machine in which the partition (90) is provided with a heat insulating material (93) having a lower thermal conductivity than the material constituting the expansion mechanism (70). The fluid machine according to any one of claims 1 to 5,
A fluid machine in which fins (95) are provided on the outer surface of the expansion mechanism (70). The fluid machine according to any one of claims 2 to 6,
In the casing (31), a fluid machine in which an oil inflow portion (91), a compression mechanism (50), and an expansion mechanism (70) are arranged in order from the bottom thereof. The fluid machine according to any one of claims 2 to 6,
In the casing (31), a fluid mechanism in which an expansion mechanism (70), an oil inflow portion (91), and a compression mechanism (50) are arranged in order from the bottom thereof. The fluid machine according to any one of claims 1 to 8,
A fluid machine in which an electric motor (40) for driving a compression mechanism (50) is disposed in the high-pressure space (102). The fluid machine according to any one of claims 1 to 9,
A fluid machine that performs expansion and compression strokes in a vapor compression refrigeration cycle using carbon dioxide as a refrigerant.

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