JP2010163934A - Expander - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure the reliability of an expander connected to a refrigerant circuit while enabling the change of the amount of refrigerant flowing thereinto. <P>SOLUTION: In a compression/expansion unit (30) connected to the refrigerant circuit, a compression mechanism (50), a motor (45), and an expansion mechanism (60) housed in a casing (31) are connected to each other through a shaft (40). The expansion mechanism (60) is a rotary fluid machine. A cylinder space (90) is formed in the expansion mechanism (60). The cylinder space (90) is partitioned into an auxiliary space (91) and a space for driving (92) by a piston member (93). The auxiliary space (91) is connected to a first fluid chamber (72) which constitutes an expansion chamber. An oil inflow tube (101) for supplying a refrigerator oil into the space for driving (92) and an oil outflow tube (102) for discharging the refrigerator oil from the space for driving (92) are connected to the space for driving (92). When the refrigerator oil flows into or from the space for driving (92), the piston member (93) moves and the volume of the auxiliary space (91) is changed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an expander connected to a refrigerant circuit that performs a refrigeration cycle.

  Conventionally, an expander connected to a refrigerant circuit that performs a refrigeration cycle is known. This expander is constituted by a fluid machine, and is for recovering the energy of the high-pressure refrigerant in the refrigerant circuit as power. The power generated in the expander is used to drive the compressor of the refrigerant circuit or to drive the generator. Patent Document 1 discloses this type of expander. The expander includes an expansion mechanism that forms a fluid chamber. This expansion mechanism is constituted by a rotary fluid machine which is a kind of positive displacement fluid machine.

  Here, the circulation amount of the refrigerant in the refrigerant circuit varies depending on the operating conditions of the refrigeration cycle. For this reason, about the expander connected to a refrigerant circuit, it is desirable that the amount of refrigerant passing through the expander per unit time can be changed. Therefore, in the expander disclosed in Patent Document 1, the amount of refrigerant passing through the expander per unit time is variable by changing the volume of the refrigerant flowing into the expansion mechanism in one inflow stroke.

Specifically, in the expander disclosed in Patent Document 1, an auxiliary chamber communicating with the fluid chamber is formed in the expansion mechanism. And in this expander, the volume of the refrigerant | coolant which flows in into an expansion mechanism is changed in one inflow stroke by moving the piston which forms an auxiliary chamber, and changing the volume of an auxiliary chamber.
JP 2006-046257 A

  In the expander disclosed in Patent Document 1, a rod is connected to a piston forming an auxiliary chamber, and the piston is moved by driving the piston through the rod. When the piston is driven by such a mechanical mechanism, there is a problem that the possibility of troubles such as failure of the piston driving mechanism is increased.

  This invention is made | formed in view of this point, The objective is to ensure reliability, making it possible to change the refrigerant | coolant amount which flows in about the expander connected to a refrigerant circuit.

  The first invention is directed to an expander connected to a refrigerant circuit (20) that performs a refrigeration cycle. The expansion mechanism (60) includes a expansion mechanism (60) configured by a positive displacement fluid machine that forms the fluid chamber (72), and the refrigerant expands in the fluid chamber (72). Movement for partitioning the auxiliary space (91) communicating with the chamber (72), the driving space (92) filled with the incompressible fluid, the auxiliary space (91) and the driving space (92) And a piston member (93) that can be freely moved to supply the incompressible fluid to the drive space (92) and to discharge the incompressible fluid from the drive space (92). By moving (93), the volume of the auxiliary space (91) is changed.

  In the expansion mechanism (60) of the first invention, a fluid chamber (72) and an auxiliary space (91) communicating with the fluid chamber (72) are formed. In the inflow stroke in which the refrigerant flows into the expansion mechanism (60), the refrigerant flows into the fluid chamber (72) and the auxiliary space (91). In addition, a driving space (92) is formed in the expansion mechanism (60), and a space between the auxiliary space (91) and the driving space (92) is partitioned by the piston member (93). The drive space (92) is filled with an incompressible fluid. When the incompressible fluid is supplied to the drive space (92), the piston member (93) moves and the volume of the auxiliary space (91) decreases. When the incompressible fluid is discharged from the drive space (92), the piston member (93) moves and the volume of the auxiliary space (91) increases. When the volume of the auxiliary space (91) changes, the amount of refrigerant flowing into the expansion mechanism (60) changes in one inflow stroke.

  According to a second invention, in the first invention, the refrigerating machine oil present in the refrigerant circuit (20) is used as the incompressible fluid filling the drive space (92).

  In the second invention, refrigeration oil is used as the incompressible fluid for driving the piston member (93). In the expansion mechanism (60) of the present invention, the piston member (93) is driven by allowing the refrigerating machine oil to flow into and out of the drive space (92).

  According to a third aspect, in the second aspect, the refrigerating machine oil stored in a portion of the refrigerant circuit (20) where the high-pressure gas refrigerant discharged from the compressor (50) of the refrigerant circuit (20) is present. And an oil inflow passage (101) for allowing the refrigerant to flow into the drive space (92), and refrigeration oil in the drive space (92) is drawn into the compressor (50) in the refrigerant circuit (20). And an oil outflow passage (102) for flowing out to a portion through which the low-pressure refrigerant flows.

  In the third invention, the expander (30) is provided with the oil inflow passage (101) and the oil outflow passage (102). The portion of the refrigerant circuit (20) where the high-pressure gas refrigerant discharged from the compressor (50) is present has the highest pressure in the refrigerant circuit (20). That is, the pressure in this portion is higher than the pressure in the drive space (92). Therefore, the refrigeration oil stored in this portion flows into the drive space (92) through the oil inflow passage (101). On the other hand, the portion of the refrigerant circuit (20) through which the low-pressure refrigerant sucked into the compressor (50) flows has the lowest pressure in the refrigerant circuit (20). That is, the pressure in this portion is lower than the pressure in the drive space (92). Therefore, the refrigeration oil in the drive space (92) is discharged from the drive space (92) through the oil outflow passage (102).

  According to a fourth invention, in the first invention, the liquid refrigerant present in the refrigerant circuit (20) is used as the incompressible fluid filling the drive space (92).

  In the fourth invention, liquid refrigerant is used as the incompressible fluid for driving the piston member (93). In the expansion mechanism (60) of the present invention, the piston member (93) is driven by allowing the liquid refrigerant to flow into and out of the drive space (92).

  According to a fifth invention, in the fourth invention, the high-pressure liquid refrigerant before expansion flowing through a portion of the refrigerant circuit (20) connected to the inflow side of the expansion mechanism (60) is supplied to the drive space (92). A refrigerant inflow passage (111) for inflow into the drive space (92) and a liquid refrigerant in the drive space (92) connected to the outflow side of the expansion mechanism (60) in the refrigerant circuit (20) to expand the low pressure after expansion A refrigerant outflow passage (112) for flowing out to a portion through which the refrigerant flows is provided.

  In the fifth invention, the expander (30) is provided with the refrigerant inflow passage (111) and the refrigerant outflow passage (112). In the refrigerant circuit (20), the portion connected to the inflow side of the expansion mechanism (60) is the high-pressure liquid refrigerant before expansion (that is, the incompressible high-pressure liquid refrigerant) flows, and this high-pressure liquid refrigerant flows into the refrigerant. It flows into the drive space (92) through the passage (111). On the other hand, in the portion of the refrigerant circuit (20) connected to the outflow side of the expansion mechanism (60), the low-pressure refrigerant after expansion flows, and the refrigerant in the drive space (92) is directed toward this portion. It flows out through the outflow passage (112).

  According to a sixth invention, in any one of the first to fifth inventions, there is provided an elastic member (94) for applying a force in the direction of the drive space (92) to the piston member (93). It is to be prepared.

  Here, in the expansion stroke in which the refrigerant expands in the fluid chamber (72) of the expansion mechanism (60), the pressure in the fluid chamber (72) gradually decreases, and the auxiliary chamber communicates with the fluid chamber (72) accordingly. The pressure in the space (91) also gradually decreases. For this reason, during operation of the expander (30), the pressure in the auxiliary space (91) acting on the piston member (93) changes periodically, and the piston member (93) may vibrate due to this change. There is.

  On the other hand, in the sixth invention, the piston member (93) is pressed against the incompressible fluid filling the drive space (92) by the force received from the elastic member (94). Therefore, even if the pressure in the auxiliary space (91) fluctuates during operation of the expander (30), the piston member (93) is incompressible in the drive space (92) by the elastic member (94). It is kept pressed against the fluid.

  A seventh invention is the fluid machine for compressing the refrigerant in any one of the first to sixth inventions, and a compression mechanism (50) constituting the compressor of the refrigerant circuit (20), A rotation shaft (40) that connects the compression mechanism (50) to the expansion mechanism (60) is provided.

  In the seventh invention, the expansion mechanism (60) and the compression mechanism (50) are connected to the rotating shaft (40). The power generated in the expansion mechanism (60) is transmitted to the compression mechanism (50) by the rotating shaft (40) and used to drive the compression mechanism (50).

  In the expander (30) of the present invention, the piston member (93) is moved by allowing an incompressible fluid to flow into and out of the drive space (92) formed in the expansion mechanism (60). That is, in the expander (30) of the present invention, the piston member (93) for changing the volume of the auxiliary space (91) controls the flow of the incompressible fluid without using a mechanical mechanism. Is driven by that. Therefore, according to the present invention, the cause of the trouble of the expander (30) can be reduced as compared with the case where the piston member (93) is driven using a mechanical mechanism, and the reliability of the expander (30) can be reduced. Can be improved.

  In the second and third inventions, refrigeration oil is used as the incompressible fluid for driving the piston member (93). That is, in these inventions, in order to lubricate the compressor (50) and the expander (30), the piston member (93) is driven by using the refrigerating machine oil that inevitably exists in the refrigerant circuit (20). be able to. Therefore, according to these inventions, it is possible to drive the piston member (93) using fluid while keeping the configuration of the expander (30) simple.

  In particular, in the third aspect of the invention, the refrigerating machine oil is supplied to the drive space (92) from the highest pressure portion in the refrigerant circuit (20) through the oil inflow passage (101) and driven through the oil outflow passage (102). Refrigerating machine oil is discharged from the working space (92) to the lowest pressure part in the refrigerant circuit (20). Therefore, according to this invention, the supply of the refrigerating machine oil to the drive space (92) and the discharge of the refrigerating machine oil from the drive space (92) can be reliably performed, and the piston member (93) can be reliably It can be moved.

  In the fourth and fifth inventions, the liquid refrigerant is used as the incompressible fluid for driving the piston member (93). That is, in these inventions, the piston member (93) can be driven using the liquid refrigerant that inevitably exists in the refrigerant circuit (20). Therefore, according to these inventions, it is possible to drive the piston member (93) using fluid while keeping the configuration of the expander (30) simple.

  In particular, in the fifth aspect of the invention, the refrigerant is supplied from the inflow side portion of the expander (30), which is the portion where the incompressible high-pressure refrigerant exists in the refrigerant circuit (20), to the drive space (92). The refrigerant is discharged from the drive space (92) to a portion where the refrigerant flows, which is supplied and flows when passing through the expansion mechanism (60). Therefore, according to the present invention, the supply of the liquid refrigerant to the drive space (92) and the discharge of the liquid refrigerant from the drive space (92) can be reliably performed, and the piston member (93) can be reliably connected. It can be moved.

  In the sixth aspect, the piston member (93) is pressed against the incompressible fluid in the drive space (92) by the elastic member (94). For this reason, even if the pressure in the auxiliary space (91) fluctuates during operation of the expander (30), the vibration of the piston member (93) caused by the fluctuation can be suppressed, and the piston member (93) can be damaged. Generation of noise can be prevented in advance.

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

Embodiment 1 of the Invention
A first embodiment of the present invention will be described. This embodiment is an air conditioner (10) including a compression / expansion unit (30) that is an expander.

<Overall configuration of air conditioner>
As shown in FIG. 1, the air conditioner (10) is of a so-called separate type, and includes an outdoor unit (11) and an indoor unit (13). 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 (30). It is stored. The indoor unit (13) houses an indoor fan (14) and an indoor heat exchanger (24). The outdoor unit (11) is installed outdoors, and the indoor unit (13) is installed indoors. The outdoor unit (11) and the indoor unit (13) are connected by a pair of connecting pipes (15, 16). Details of the compression / expansion unit (30) will be described later.

The air conditioner (10) is provided with a refrigerant circuit (20). The refrigerant circuit (20) is a closed circuit to which a compression / expansion unit (30), an indoor heat exchanger (24), and the like are connected. The refrigerant circuit (20) is filled with carbon dioxide (CO ₂ ) as a refrigerant.

  The outdoor heat exchanger (23) and the indoor heat exchanger (24) are both fin-and-tube heat exchangers for exchanging heat between the refrigerant and air. In the outdoor heat exchanger (23), the refrigerant circulating in the refrigerant circuit (20) exchanges heat with outdoor air. In the indoor heat exchanger (24), the refrigerant circulating in the refrigerant circuit (20) exchanges heat with room air.

  The first four-way selector valve (21) has four ports. The first four-way switching valve (21) has a first port connected to the discharge pipe (36) of the compression / expansion unit (30) and a second port connected to the indoor heat exchanger (15) via the connecting pipe (15). 24), a third port is connected to one end of the outdoor heat exchanger (23), and a fourth port is connected to the suction port (32) of the compression / expansion unit (30). The first four-way switching valve (21) is in a state where the first port and the second port communicate with each other and the third port and the fourth port communicate with each other (a state indicated by a solid line in FIG. 1). Then, the first port and the third port communicate with each other and the second port and the fourth port communicate with each other (state indicated by a broken line in FIG. 1).

  The second four-way selector valve (22) has four ports. The second four-way selector valve (22) has a first port at the outflow port (35) of the compression / expansion unit (30), a second port at the other end of the outdoor heat exchanger (23), The third port is connected to the other end of the indoor heat exchanger (24) via the connecting pipe (16), and the fourth port is connected to the inflow port (34) of the compression / expansion unit (30). The second four-way selector valve (22) is in a state where the first port and the second port communicate with each other and the third port and the fourth port communicate with each other (a state indicated by a solid line in FIG. 1). Then, the first port and the third port communicate with each other and the second port and the fourth port communicate with each other (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 (45), and an expansion mechanism (60) are arranged in order from the bottom to the top.

  A discharge pipe (36) is attached to the casing (31). The discharge pipe (36) is disposed between the electric motor (45) and the expansion mechanism (60) and communicates with the internal space of the casing (31).

  The electric motor (45) is disposed at the center in the longitudinal direction of the casing (31). The electric motor (45) includes a stator (46) and a rotor (47). The stator (46) is fixed to the casing (31). The rotor (47) is disposed inside the stator (46). Further, the main shaft portion (44) of the shaft (40) passes through the rotor (47) coaxially with the rotor (47).

  The shaft (40) constitutes a rotation axis. In the shaft (40), two lower eccentric portions (58, 59) are formed on the lower end side, and two large-diameter eccentric portions (41, 42) are formed on the upper end side.

  The two lower eccentric portions (58, 59) are formed to have a larger diameter than the main shaft portion (44), the lower one being the first lower eccentric portion (58) and the upper one being the second. A lower eccentric portion (59) is formed. In the first lower eccentric portion (58) and the second lower eccentric portion (59), the eccentric directions of the main shaft portion (44) with respect to the axial center are reversed.

  The two large-diameter eccentric parts (41, 42) are formed with a larger diameter than the main shaft part (44), the lower one constitutes the first large-diameter eccentric part (41), and the upper one is A second large-diameter eccentric portion (42) is configured. The first large-diameter eccentric part (41) and the second large-diameter eccentric part (42) are both eccentric in the same direction. The outer diameter of the second large-diameter eccentric part (42) is larger than the outer diameter of the first large-diameter eccentric part (41). Further, the amount of eccentricity of the main shaft portion (44) with respect to the shaft center is larger in the second large-diameter eccentric portion (42) than in the first large-diameter eccentric portion (41).

  The compression mechanism (50) constitutes an oscillating piston type rotary compressor. The compression mechanism (50) includes two cylinders (51, 52) and two pistons (57). In the compression mechanism (50), in order from the bottom to the top, the rear head (55), the first cylinder (51), the intermediate plate (56), the second cylinder (52), and the front head (54) Are stacked.

  One cylindrical piston (57) is disposed inside each of the first and second cylinders (51, 52). Although not shown, a flat plate-like blade projects from the side surface of the piston (57), and this blade is supported by the cylinder (51, 52) via a swing bush. The piston (57) in the first cylinder (51) engages with the first lower eccentric portion (58) of the shaft (40). On the other hand, the piston (57) in the second cylinder (52) engages with the second lower eccentric portion (59) of the shaft (40). Each piston (57, 57) has its inner peripheral surface in sliding contact with the outer peripheral surface of the lower eccentric portion (58, 59), and its outer peripheral surface is in sliding contact with the inner peripheral surface of the cylinder (51, 52). A compression chamber (53) is formed between the outer peripheral surface of the piston (57, 57) and the inner peripheral surface of the cylinder (51, 52).

  One suction port (33) is formed in each of the first and second cylinders (51, 52). Each suction port (33) penetrates the cylinder (51, 52) in the radial direction, and its terminal end opens on the inner peripheral surface of the cylinder (51, 52). Each suction port (33) is extended to the outside of the casing (31) by piping.

  One discharge port is formed in each of the front head (54) and the rear head (55). The discharge port of the front head (54) allows the compression chamber (53) in the second cylinder (52) to communicate with the internal space of the casing (31). The discharge port of the rear head (55) allows the compression chamber (53) in the first cylinder (51) to communicate with the internal space of the casing (31). Each discharge port is provided with a discharge valve consisting of a reed valve at its end, and is opened and closed by this discharge valve. In FIG. 2, the discharge port and the discharge valve are not shown. The gas refrigerant discharged from the compression mechanism (50) into the internal space of the casing (31) is sent out from the compression / expansion unit (30) through the discharge pipe (36).

  Refrigerating machine oil is stored in the internal space of the casing (31). This refrigerating machine oil is collected at the bottom of the internal space of the casing (31). As described above, the high-pressure gas refrigerant compressed in the compression mechanism (50) is discharged into the internal space of the casing (31). For this reason, the pressure of the refrigerating machine oil stored in the casing (31) becomes equal to the pressure of the high-pressure gas refrigerant discharged from the compression mechanism (50). The high-pressure refrigerating machine oil stored in the casing (31) is supplied to the compression mechanism (50) and the expansion mechanism (60) through an oil supply passage formed in the shaft (40).

  The expansion mechanism (60) is a so-called oscillating piston type fluid machine. The expansion mechanism (60) is provided with two pairs of cylinders (71, 81) and pistons (75, 85). The expansion mechanism (60) includes a front head (61), an intermediate plate (63), and a rear head (62).

  In the expansion mechanism (60), the front head (61), the first cylinder (71), the intermediate plate (63), the second cylinder (81), and the rear head (62) are stacked in order from bottom to top. It has become. In this state, the first cylinder (71) has its lower end face closed by the front head (61) and its upper end face closed by the intermediate plate (63). On the other hand, the second cylinder (81) has its lower end face closed by the intermediate plate (63) and its upper end face closed by the rear head (62). The inner diameter of the second cylinder (81) is larger than the inner diameter of the first cylinder (71). The shaft (40) passes through the stacked front head (61), first cylinder (71), intermediate plate (63), second cylinder (81), and rear head (62).

  As shown in FIGS. 3 and 4, a first piston (75) is provided in the first cylinder (71), and a second piston (85) is provided in the second cylinder (81). The first and second pistons (75, 85) are both formed in an annular shape or a cylindrical shape. The outer diameter of the first piston (75) and the outer diameter of the second piston (85) are equal to each other. The first large-diameter eccentric portion (41) penetrates the first piston (75), and the second large-diameter eccentric portion (42) penetrates the second piston (85). A first fluid chamber (72) is formed in the first cylinder (71) between the inner peripheral surface thereof and the outer peripheral surface of the first piston (75). A second fluid chamber (82) is formed in the second cylinder (81) between the inner peripheral surface thereof and the outer peripheral surface of the second piston (85).

  One blade (76, 86) is provided integrally with each of the first and second pistons (75, 85). The blades (76, 86) are formed in a plate shape extending in the radial direction of the piston (75, 85), and protrude outward from the outer peripheral surface of the piston (75, 85).

  Each cylinder (71, 81) is provided with a pair of bushes (77, 87). Each bush (77, 87) is a small piece formed such that the inner surface is a flat surface and the outer surface is a circular arc surface. The pair of bushes (77, 87) are installed with the blade (76, 86) sandwiched therebetween. Each bush (77, 87) slides on its inner surface with the blade (76, 86) and its outer surface with the cylinder (71, 81). The blade (76, 86) integral with the piston (75, 85) is supported by the cylinder (71, 81) via the bush (77, 87) and is rotatable with respect to the cylinder (71, 81). And you can move forward and backward. The first cylinder (71) and the second cylinder (81) are arranged in such a posture that the positions of the bushes (77, 87) in the respective circumferential directions coincide.

  The first fluid chamber (72) in the first cylinder (71) is partitioned by a first blade (76) integral with the first piston (75), and the first blade (76) in FIGS. The left side is a first high pressure chamber (73) on the high pressure side, and the right side is a first low pressure chamber (74) on the low pressure side. The second fluid chamber (82) in the second cylinder (81) is partitioned by a second blade (86) integral with the second piston (85), and the second blade (86) in FIGS. The left side is a high pressure side second high pressure chamber (83), and the right side is a low pressure side second low pressure chamber (84).

  An inflow port (34) is formed in the first cylinder (71). The inflow port (34) opens at a position slightly on the left side of the bush (77) in FIGS. 3 and 4 in the inner peripheral surface of the first cylinder (71). The inflow port (34) can communicate with the first high pressure chamber (73). On the other hand, the outflow port (35) is formed in the second cylinder (81). The outflow port (35) opens at a position slightly on the right side of the bush (87) in FIGS. 3 and 4 in the inner peripheral surface of the second cylinder (81). The outflow port (35) can communicate with the second low pressure chamber (84).

  A communication path (64) is formed in the intermediate plate (63). The communication path (64) penetrates the intermediate plate (63) in the thickness direction. On the surface of the intermediate plate (63) on the first cylinder (71) side, one end of the communication path (64) is opened at a location on the right side of the first blade (76). On the surface of the intermediate plate (63) on the second cylinder (81) side, the other end of the communication path (64) is opened at a location on the left side of the second blade (86). The communication path (64) extends obliquely with respect to the thickness direction of the intermediate plate (63), and allows the first low pressure chamber (74) and the second high pressure chamber (83) to communicate with each other.

  In the expansion mechanism (60) configured as described above, the first cylinder (71), the bush (77) provided therein, the first piston (75), and the first blade (76) are provided. A first rotary mechanism (70) is configured. The second cylinder (81), the bush (87) provided there, the second piston (85), and the second blade (86) constitute a second rotary mechanism (80). . Further, in this expansion mechanism (60), the displacement volume of the second rotary mechanism section (80) (in comparison with the displacement volume of the first rotary mechanism section (70) (that is, the maximum volume of the first fluid chamber (72)) ( That is, the maximum volume of the second fluid chamber (82) is larger.

  As described above, in the expansion mechanism (60), the timing at which the first blade (76) retreats most to the outside of the first cylinder (71) and the second blade (86) to the outside of the second cylinder (81). The timing of the most withdrawal is synchronized. That is, the process in which the volume of the first low pressure chamber (74) decreases in the first rotary mechanism (70) and the volume of the second high pressure chamber (83) increases in the second rotary mechanism (80). The going process is synchronized (see FIG. 4). In addition, as described above, the first low pressure chamber (74) of the first rotary mechanism (70) and the second high pressure chamber (83) of the second rotary mechanism (80) communicate with the communication path (64). Are in communication with each other. The first low pressure chamber (74), the communication passage (64), and the second high pressure chamber (83) form one closed space, and this closed space constitutes the expansion chamber (66).

  As shown in FIG. 2, in the expansion mechanism (60), a cylinder space (90) is formed in the front head (61). The cylinder space (90) is formed by a bottomed hole extending from the outer peripheral surface of the front head (61) toward the center thereof. The bottomed hole forming the cylinder space (90) has a circular cross-sectional shape, and the opening end on the outer peripheral surface of the front head (61) is closed by the casing (31).

  A piston member (93) is accommodated in the cylinder space (90). The piston member (93) is formed in a slightly thick disk shape and is movable in the axial direction of the cylinder space (90). The cylinder space (90) is divided into two spaces by the piston member (93). In the two spaces defined by the piston member (93), the space on the bottom side of the hole forming the cylinder space (90) (the left side of the piston member (93) in FIG. 2) constitutes the auxiliary space (91). The remaining space constitutes a drive space (92).

  The front head (61) is formed with a connection passage (95) for communicating the auxiliary space (91) with the first fluid chamber (72) of the first rotary mechanism (70). One end of the connection passage (95) opens near the bottom surface of the hole forming the cylinder space (90), and the other end opens on the front surface (upper surface in FIG. 2) of the front head (61). As shown in FIG. 3, on the front surface of the front head (61), the connection passage (95) opens at a position along the inner peripheral surface of the first cylinder (71). In addition, on the front surface of the front head (61), the connection passage (95) opens at a position advanced about 270 ° counterclockwise in FIG. 3 from the position of the first blade (76). The opening position of the connection passage (95) on the front surface of the front head (61) is from the position advanced about 180 ° counterclockwise in FIG. 3 from the position of the first blade (76), to the communication passage ( It is desirable to set between 64 and the position near the right side of the opening.

  A coil spring (94), which is an elastic member, is accommodated in the auxiliary space (91). The coil spring (94) has one end fixed to the piston member (93) and the other end fixed to the casing (31). The coil spring (94) applies a force in a direction in which the piston member (93) is pulled toward the drive space (92) to the piston member (93).

  As shown in FIG. 2, the compression / expansion unit (30) includes an oil circulation pipe (100), an oil inflow pipe (101) constituting an oil inflow passage, and an oil outflow pipe (102) constituting an oil outflow passage. And are provided.

  One end of the oil circulation pipe (100) passes through the casing (31) and opens into the drive space (92). One end of an oil inflow pipe (101) and one end of an oil outflow pipe (102) are connected to the other end of the oil circulation pipe (100). A capillary tube (103) is provided in the middle of the oil circulation pipe (100). The capillary tube (103) is provided in order to suppress the flow rate of the fluid (refrigeration machine oil) flowing through the oil circulation pipe (100).

  The other end of the oil inflow pipe (101) passes through the bottom of the casing (31) and opens into the internal space of the casing (31). The other end of the oil inflow pipe (101) is immersed in refrigeration oil stored at the bottom of the casing (31). An inflow side electromagnetic valve (104) is provided in the middle of the oil inflow pipe (101).

  The other end of the oil outflow pipe (102) is connected to a pipe connected to the suction port (32) of the compression mechanism (50) (that is, a pipe through which the low-pressure gas refrigerant sucked into the compression mechanism (50) flows). . In the middle of the oil outflow pipe (102), an outflow side solenoid valve (105) is provided.

-Driving action-
The operation of the air conditioner (10) will be described. Here, the operation of the air conditioner (10) during the cooling operation and the heating operation will be described, and then the operation of the expansion mechanism (60) will be described.

<Cooling operation>
During the cooling operation, the first four-way switching valve (21) and the second four-way switching valve (22) are switched to the state indicated by the broken line in FIG. When the electric motor (45) of the compression / expansion unit (30) is energized in this state, the refrigerant circulates in the refrigerant circuit (20) to perform a vapor compression refrigeration cycle.

  The refrigerant compressed by the compression mechanism (50) is discharged from the compression / expansion unit (30) through the discharge pipe (36). In this state, the refrigerant pressure is higher than the critical pressure. This discharged refrigerant is sent to the outdoor heat exchanger (23) through the first four-way switching valve (21). In the outdoor heat exchanger (23), the flowed refrigerant radiates heat to the outdoor air.

  The refrigerant radiated by the outdoor heat exchanger (23) passes through the second four-way switching valve (22) and flows into the expansion mechanism (60) of the compression / expansion unit (30) through the inflow port (34). In the expansion mechanism (60), the high-pressure refrigerant expands and the shaft (40) is driven. The low-pressure refrigerant after expansion flows out from the compression / expansion unit (30) through the outflow port (35), passes through the second four-way switching valve (22), and is sent to the indoor heat exchanger (24).

  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 low-pressure gas refrigerant coming out of the indoor heat exchanger (24) passes through the first four-way switching valve (21) and is sucked into the compression mechanism (50) of the compression / expansion unit (30) through the suction port (32). Is done. The compression mechanism (50) compresses and discharges the sucked refrigerant.

<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 (45) of the compression / expansion unit (30) is energized in this state, the refrigerant circulates in the refrigerant circuit (20) to perform a vapor compression refrigeration cycle.

  The refrigerant compressed by the compression mechanism (50) is discharged from the compression / expansion unit (30) through the discharge pipe (36). In this state, the refrigerant pressure is higher than the critical pressure. The discharged refrigerant passes through the first four-way switching valve (21) and is sent to the indoor heat exchanger (24). In the indoor heat exchanger (24), the refrigerant that has flowed in dissipates heat to the room air, and the room air is heated.

  The refrigerant radiated by the indoor heat exchanger (24) passes through the second four-way switching valve (22) and flows into the expansion mechanism (60) of the compression / expansion unit (30) through the inflow port (34). In the expansion mechanism (60), the high-pressure refrigerant expands and the shaft (40) is driven. The low-pressure refrigerant after expansion flows out from the compression / expansion unit (30) through the outflow port (35), passes through the second four-way switching valve (22), and is sent to the outdoor heat exchanger (23).

  In the outdoor heat exchanger (23), the refrigerant that has flowed in absorbs heat from the outdoor air and evaporates. The low-pressure gas refrigerant discharged from the outdoor heat exchanger (23) passes through the first four-way switching valve (21) and is sucked into the compression mechanism (50) of the compression / expansion unit (30) through the suction port (32). Is done. The compression mechanism (50) compresses and discharges the sucked refrigerant.

<Operation of expansion mechanism>
The operation of the expansion mechanism (60) will be described with reference to FIG.

  First, a process in which the supercritical high pressure refrigerant flows into the first high pressure chamber (73) of the first rotary mechanism (70) will be described.

  When the shaft (40) rotates slightly from the state where the rotation angle is 0 °, the contact position between the first piston (75) and the first cylinder (71) passes through the opening of the inflow port (34), and the inflow port ( 34) The high-pressure refrigerant begins to flow from the first high-pressure chamber (73). Thereafter, as the rotation angle of the shaft (40) gradually increases to 90 °, 180 °, and 270 °, the high-pressure refrigerant flows into the first high-pressure chamber (73). The inflow of the high-pressure refrigerant into the first high-pressure chamber (73) continues until the rotation angle of the shaft (40) reaches 360 °. Further, the auxiliary space (91) communicates with the first high pressure chamber (73) through the connection passage (95) until the rotation angle of the shaft (40) reaches from 270 ° to 360 °. Accordingly, during this time, the high-pressure refrigerant also flows into the auxiliary space (91).

  Next, the process of expanding the refrigerant in the expansion mechanism (60) will be described.

  When the shaft (40) is slightly rotated from the state where the rotation angle is 0 °, the first low pressure chamber (74) and the second high pressure chamber (83) communicate with each other via the communication passage (64), and the first low pressure chamber The refrigerant begins to flow from (74) into the second high pressure chamber (83). Thereafter, as the rotation angle of the shaft (40) gradually increases to 90 °, 180 °, and 270 °, the volume of the first low pressure chamber (74) gradually decreases and the volume of the second high pressure chamber (83) gradually increases. As a result, the volume of the expansion chamber (66) gradually increases. This increase in the volume of the expansion chamber (66) continues until just before the rotation angle of the shaft (40) reaches 360 °.

  The refrigerant in the expansion chamber (66) expands while the pressure drops in the process of increasing the volume of the expansion chamber (66). The first piston (75) is driven by the internal pressure difference between the first high pressure chamber (73) and the first low pressure chamber (74), while the internal pressure between the second high pressure chamber (83) and the second low pressure chamber (84). The second piston (85) is driven by the difference, and as a result, the shaft (40) is rotationally driven. Thus, the refrigerant in the first low pressure chamber (74) flows through the communication passage (64) while expanding into the second high pressure chamber (83). Further, the auxiliary space (91) communicates with the first low pressure chamber (74) constituting the expansion chamber (66) until the rotation angle of the shaft (40) reaches from 0 ° to 270 °. For this reason, the refrigerant in the auxiliary space (91) flows into the first low pressure chamber (74) and expands as the internal pressure of the expansion chamber (66) decreases.

  Finally, the process in which the refrigerant flows out from the second low pressure chamber (84) of the second rotary mechanism (80) will be described.

  The second low pressure chamber (84) starts to communicate with the outflow port (35) when the rotation angle of the shaft (40) is 0 °. That is, the refrigerant starts to flow from the second low pressure chamber (84) to the outflow port (35). After that, the shaft (40) has a rotation angle gradually increased to 90 °, 180 °, and 270 °, and after the expansion from the second low pressure chamber (84) until the rotation angle reaches 360 °. The low-pressure refrigerant flows out.

<Volume adjustment operation of compression / expansion unit>
In the compression / expansion unit (30), an operation of operating the inflow side solenoid valve (104) or the outflow side solenoid valve (105) is performed in order to change the volume of the auxiliary space (91).

  Specifically, in order to reduce the volume of the auxiliary space (91), the inflow side electromagnetic valve (104) is opened. The outflow side solenoid valve (105) is kept closed. In the state where the inflow side solenoid valve (104) is open, the high-pressure refrigerating machine oil stored in the casing (31) passes through the oil inflow pipe (101) and the oil circulation pipe (100) in this order to drive space (92 ). When the refrigeration oil flows into the drive space (92), the piston member (93) is pushed toward the auxiliary space (91), and as a result, the volume of the auxiliary space (91) decreases.

  When the volume of the auxiliary space (91) is decreased, the amount of decrease in the volume of the auxiliary space (91) changes according to the time during which the inflow side solenoid valve (104) is open. In other words, if the time during which the inflow side solenoid valve (104) is opened is lengthened, the amount of refrigerating machine oil flowing into the drive space (92) increases and the amount of movement of the piston member (93) increases. (91) The volume reduction amount increases. In addition, if the time during which the inflow side solenoid valve (104) is opened is shortened, the amount of refrigerating machine oil flowing into the drive space (92) decreases and the amount of movement of the piston member (93) decreases. The volume reduction amount of (91) becomes smaller.

  On the other hand, when increasing the volume of the auxiliary space (91), the outflow side solenoid valve (105) is opened. The inflow side solenoid valve (104) is kept closed. When the outflow side solenoid valve (105) is open, the refrigeration oil in the drive space (92) flows out to the oil distribution pipe (100). The refrigerating machine oil flows into the oil outflow pipe (102) from the oil circulation pipe (100), and is then sucked into the compression mechanism (50) together with the low-pressure gas refrigerant. When the refrigeration oil flows out from the drive space (92), the piston member (93) is pulled back toward the drive space (92), and as a result, the volume of the auxiliary space (91) increases.

  When the volume of the auxiliary space (91) is increased, the increase amount of the volume of the auxiliary space (91) changes according to the time during which the outflow side solenoid valve (105) is open. In other words, if the time during which the outflow side solenoid valve (105) is opened is lengthened, the amount of refrigerating machine oil flowing out from the drive space (92) increases and the amount of movement of the piston member (93) increases. (91) Increase in volume increases. In addition, if the time during which the outflow side solenoid valve (105) is opened is shortened, the amount of refrigerating machine oil flowing out from the drive space (92) decreases and the amount of movement of the piston member (93) decreases. The increase in volume of (91) becomes smaller.

  When the adjustment of the volume of the auxiliary space (91) is completed, the inflow side solenoid valve (104) and the outflow side solenoid valve (105) are kept closed. In this state, the driving space (92) is maintained in a state filled with the refrigerating machine oil that is an incompressible fluid, and the refrigerating machine oil does not flow into and out of the driving space (92). For this reason, when the inflow side solenoid valve (104) and the outflow side solenoid valve (105) are closed, the piston member (93) is substantially fixed, and the volume of the auxiliary space (91) is constant. Retained.

  When the volume of the auxiliary space (91) is changed, the volume of the high-pressure refrigerant flowing into the expansion mechanism (60) changes while the shaft (40) rotates once. That is, in the expansion mechanism (60) of the present embodiment, one inflow stroke is performed every time the shaft (40) rotates once. Therefore, when the volume of the auxiliary space (91) is changed, in the one inflow stroke The volume of the high-pressure refrigerant flowing into the expansion mechanism (60) changes.

  The necessity of changing the volume of the auxiliary space (91) will be briefly described.

  The power output from the expansion mechanism (60) is maximized because the refrigerant pressure in the expansion chamber (66) at the time when the volume of the expansion chamber (66) is maximized is the outflow port of the expansion mechanism (60). This is the case where the refrigerant pressure in the pipe connected to (35) is substantially equal to the low pressure of the refrigeration cycle. However, the high pressure and low pressure values of the refrigeration cycle performed in the refrigerant circuit (20) vary depending on the operating conditions (for example, outdoor or indoor temperature) of the air conditioner (10). For this reason, during operation of the air conditioner (10), the refrigerant pressure in the expansion chamber (66) at the time when the volume of the expansion chamber (66) becomes maximum is applied to the outflow port (35) of the expansion mechanism (60). It may be too high or too low with respect to the refrigerant pressure in the pipe to be connected.

  When the operation state of the expansion mechanism (60) is insufficiently expanded, the refrigerant pressure in the expansion chamber (66) at the time when the volume of the expansion chamber (66) reaches the maximum is the outflow of the expansion mechanism (60). It becomes higher than the refrigerant pressure in the pipe connected to the port (35). In this case, the refrigerant flows out of the expansion mechanism (60) even though the refrigerant pressure is not sufficiently reduced in the expansion chamber (66), and the power generated in the expansion mechanism (60) is reduced. . Therefore, in such a case, the volume of the auxiliary space (91) is reduced, and the volume of the high-pressure refrigerant flowing into the expansion mechanism (60) in one inflow stroke is reduced.

  On the other hand, when the operation state of the expansion mechanism (60) is overexpanded, the refrigerant pressure in the expansion chamber (66) at the time when the volume of the expansion chamber (66) becomes maximum is the expansion mechanism (60). It becomes lower than the refrigerant pressure in the pipe connected to the outflow port (35). In this case, the refrigerant pressure in the expansion chamber (66) must be lowered to a value lower than the refrigerant pressure in the outflow port (35), and power is consumed to reduce the refrigerant pressure in the expansion chamber (66). Therefore, the power output from the expansion mechanism (60) is reduced. Therefore, in such a case, the volume of the auxiliary space (91) is increased, and the volume of the high-pressure refrigerant flowing into the expansion mechanism (60) in one inflow stroke is increased.

-Effect of Embodiment 1-
In the compression / expansion unit (30) of the present embodiment, the piston member (93) is moved by allowing the refrigerating machine oil, which is an incompressible fluid, to flow into and out of the drive space (92) formed in the expansion mechanism (60). It is moved. That is, in the compression / expansion unit (30) of the present embodiment, the piston member (93) for changing the volume of the auxiliary space (91) controls the flow of the refrigerating machine oil without using a mechanical mechanism. Is driven by that. Therefore, according to this embodiment, the cause of the trouble of the compression / expansion unit (30) can be reduced as compared with the case where the piston member (93) is driven using a mechanical mechanism, and the compression / expansion unit (30 ) Reliability can be improved.

  In the compression / expansion unit (30) of the present embodiment, as described above, refrigeration oil is used as an incompressible fluid for driving the piston member (93). That is, in this compression / expansion unit (30), the piston member (93) is utilized by utilizing the refrigerating machine oil that inevitably exists in the refrigerant circuit (20) in order to lubricate the compression mechanism (50) and the expansion mechanism (60). ) Can be driven. Therefore, according to this embodiment, it is possible to drive the piston member (93) using the fluid while keeping the configuration of the compression / expansion unit (30) simple.

  Here, the internal space of the casing (31) of the compression / expansion unit (30) is the highest pressure portion in the refrigerant circuit (20). Further, the pipe connected to the suction port (32) of the compression mechanism (50) is the part having the lowest pressure in the refrigerant circuit (20). In the compression / expansion unit (30) of the present embodiment, the refrigerating machine oil stored in the internal space of the casing (31) can be supplied to the drive space (92) through the oil inflow pipe (101). Further, in the compression / expansion unit (30), the refrigeration oil in the drive space (92) can be discharged to a pipe connected to the suction port (32) through the oil outflow pipe (102). Therefore, according to this embodiment, the supply of the refrigeration oil to the drive space (92) and the discharge of the refrigeration oil from the drive space (92) can be performed reliably, and the piston member (93) can be securely connected. It is possible to move to.

  By the way, in the expansion stroke in which the refrigerant expands in the expansion chamber (66) of the expansion mechanism (60), the pressure in the expansion chamber (66) gradually decreases, and the auxiliary space communicates with the expansion chamber (66) accordingly. The pressure of (91) also decreases gradually. For this reason, during operation of the expansion mechanism (60), the pressure in the auxiliary space (91) acting on the piston member (93) may periodically increase or decrease, and the piston member (93) may vibrate.

  On the other hand, in the compression / expansion unit (30) of the present embodiment, the piston member (93) is pressed against the refrigerating machine oil filling the drive space (92) by the force received from the coil spring (94). For this reason, even if the pressure in the auxiliary space (91) fluctuates during operation of the expansion mechanism (60), the piston member (93) is moved to the refrigerating machine oil in the drive space (92) by the coil spring (94). It is kept pressed. Therefore, according to the present embodiment, even if the pressure in the auxiliary space (91) fluctuates during operation of the expansion mechanism (60), the vibration of the piston member (93) caused by the fluctuation can be suppressed. Damage to (93) and noise can be prevented.

-Modification 1 of Embodiment 1-
As shown in FIG. 5, in the compression / expansion unit (30) of the present embodiment, an inflow side adjustment valve (106) is provided in the oil inflow pipe (101) instead of the inflow side solenoid valve (104), and the outflow side solenoid valve Instead of (105), an outflow control valve (107) may be provided in the oil outflow pipe (102). Each of the inflow side control valve (106) and the outflow side control valve (107) is an electric expansion valve having a variable opening. In this modification, by operating the inflow side adjustment valve (106) and the outflow side adjustment valve (107), the piston member (93) is moved to change the volume of the auxiliary space (91).

-Modification 2 of Embodiment 1
In the refrigerant circuit (20), an oil separator may be provided on the discharge side of the compression mechanism (50) of the compression / expansion unit (30). In this case, the oil separator is connected to the discharge pipe (36) of the compression / expansion unit (30) via a pipe, and separates the high-pressure gas refrigerant discharged from the discharge pipe (36) from the refrigeration oil contained therein. To do. The refrigerating machine oil separated from the gas refrigerant in the oil separator is supplied to a pipe connected to the suction port (32) of the compression mechanism (50), and is sucked into the compression mechanism (50) together with the low-pressure gas refrigerant.

  Thus, the oil separator separates the refrigeration oil from the high-pressure gas refrigerant. For this reason, the high pressure gas refrigerant exists in the internal space of the oil separator, and the pressure of the refrigerating machine oil temporarily stored therein becomes equal to the pressure of the high pressure gas refrigerant. Accordingly, in such a case, the oil inflow pipe (101) is connected to the oil separator instead of the casing (31) of the compression / expansion unit (30), and the high-pressure refrigeration oil in the oil separator is connected to the drive space (92 ).

<< Embodiment 2 of the Invention >>
A second embodiment of the present invention will be described. The present embodiment is obtained by changing the configuration of the compression / expansion unit (30) in the air conditioner (10) of the first embodiment.

  As shown in FIG. 6, in the compression / expansion unit (30) of this embodiment, instead of the oil circulation pipe (100), the oil inflow pipe (101), and the oil outflow pipe (102) of the first embodiment, a refrigerant A distribution pipe (110), a refrigerant inflow pipe (111), and a refrigerant outflow pipe (112) are provided. The refrigerant inflow pipe (111) constitutes a refrigerant inflow passage, and the refrigerant outflow pipe (112) constitutes a refrigerant outflow passage. The compression / expansion unit (30) of the present embodiment is configured to move the piston member (93) by allowing liquid refrigerant that is an incompressible fluid to flow into and out of the drive space (92). Yes.

  One end of the refrigerant flow pipe (110) passes through the casing (31) and opens into the drive space (92). One end of the refrigerant inflow pipe (111) and one end of the refrigerant outflow pipe (112) are connected to the other end of the refrigerant circulation pipe (110). A capillary tube (113) is provided in the middle of the refrigerant circulation pipe (110). The capillary tube (113) is provided to suppress the flow rate of the fluid (liquid refrigerant) flowing through the refrigerant circulation pipe (110).

  The other end of the refrigerant inflow pipe (111) is connected to a pipe connected to the inflow port (34) of the expansion mechanism (60) (that is, a pipe through which high-pressure liquid refrigerant before expansion flows into the expansion mechanism (60) flows). ing. An inflow side electromagnetic valve (114) is provided in the middle of the refrigerant inflow pipe (111).

  The other end of the refrigerant outflow pipe (112) is connected to a pipe connected to the outflow port (35) of the expansion mechanism (60) (that is, a pipe through which the low-pressure refrigerant after expansion flowing out of the expansion mechanism (60) flows). Yes. In the middle of the refrigerant outflow pipe (112), an outflow side electromagnetic valve (115) is provided.

-Driving action-
In the compression / expansion unit (30), an operation of operating the inflow side solenoid valve (114) or the outflow side solenoid valve (115) is performed in order to change the volume of the auxiliary space (91).

  Specifically, when reducing the volume of the auxiliary space (91), the inflow side electromagnetic valve (114) is opened. The outflow side solenoid valve (115) is kept closed. In a state where the inflow side solenoid valve (114) is open, the high-pressure liquid refrigerant before expansion flows into the drive space (92) through the refrigerant inflow pipe (111) and the refrigerant distribution pipe (110) in this order. When the liquid refrigerant flows into the drive space (92), the piston member (93) is pushed toward the auxiliary space (91), and as a result, the volume of the auxiliary space (91) decreases.

  When the volume of the auxiliary space (91) is decreased, the amount of decrease in the volume of the auxiliary space (91) changes according to the time during which the inflow side electromagnetic valve (114) is open. That is, if the time during which the inflow side solenoid valve (114) is opened is lengthened, the amount of liquid refrigerant flowing into the drive space (92) increases and the amount of movement of the piston member (93) increases. (91) The volume reduction amount increases. In addition, if the time during which the inflow side solenoid valve (114) is opened is shortened, the amount of liquid refrigerant flowing into the drive space (92) is reduced and the amount of movement of the piston member (93) is reduced. The volume reduction amount of (91) becomes smaller.

  On the other hand, when the volume of the auxiliary space (91) is increased, the outflow side electromagnetic valve (115) is opened. The inflow side solenoid valve (114) is kept closed. In a state where the outflow side solenoid valve (115) is open, the liquid refrigerant in the drive space (92) flows out to the refrigerant circulation pipe (110). This liquid refrigerant flows into the refrigerant outflow pipe (112) from the refrigerant circulation pipe (110), and then merges with the low-pressure refrigerant that has flowed out of the expansion mechanism (60). When the liquid refrigerant flows out from the drive space (92), the piston member (93) is pulled back toward the drive space (92), and as a result, the volume of the auxiliary space (91) increases.

  When the volume of the auxiliary space (91) is increased, the increase amount of the volume of the auxiliary space (91) changes according to the time during which the outflow side solenoid valve (115) is open. That is, if the time during which the outflow side solenoid valve (115) is opened is lengthened, the amount of liquid refrigerant flowing out from the drive space (92) increases and the amount of movement of the piston member (93) increases. (91) Increase in volume increases. Moreover, if the time during which the outflow side solenoid valve (115) is opened is shortened, the amount of liquid refrigerant flowing out from the drive space (92) decreases and the amount of movement of the piston member (93) decreases. The increase in volume of (91) becomes smaller.

  When the adjustment of the volume of the auxiliary space (91) is completed, the inflow side solenoid valve (114) and the outflow side solenoid valve (115) are kept closed. In this state, the drive space (92) is maintained in a state filled with the liquid refrigerant that is an incompressible fluid, and the liquid refrigerant does not flow into and out of the drive space (92). Therefore, when the inflow side solenoid valve (114) and the outflow side solenoid valve (115) are closed, the piston member (93) is substantially fixed, and the volume of the auxiliary space (91) is constant. Retained.

-Effect of Embodiment 2-
In the compression / expansion unit (30) of the present embodiment, a liquid refrigerant is used as an incompressible fluid for driving the piston member (93). That is, in the compression / expansion unit (30), the piston member (93) can be driven by using the liquid refrigerant that inevitably exists in the refrigerant circuit (20). Therefore, according to this embodiment, it is possible to drive the piston member (93) using the fluid while keeping the configuration of the compression / expansion unit (30) simple.

  Further, in the compression / expansion unit (30) of the present embodiment, the drive space (from the inflow side of the expansion mechanism (60), which is the portion where the incompressible high-pressure refrigerant is reliably present in the refrigerant circuit (20) ( The liquid refrigerant is supplied to 92), and the liquid refrigerant is discharged from the drive space (92) to the portion of the expanded low-pressure refrigerant that has flowed out of the expansion mechanism (60). Therefore, according to this embodiment, the supply of the liquid refrigerant to the drive space (92) and the discharge of the liquid refrigerant from the drive space (92) can be performed reliably, and the piston member (93) can be securely connected. It is possible to move to.

-Modification of Embodiment 2-
As shown in FIG. 7, in the compression / expansion unit (30) of the present embodiment, an inflow side adjustment valve (116) is provided in the refrigerant inflow pipe (111) instead of the inflow side electromagnetic valve (114), and the outflow side electromagnetic valve Instead of (115), an outflow control valve (117) may be provided in the refrigerant outflow pipe (112). The inflow side adjustment valve (116) and the outflow side adjustment valve (117) are both electrically variable expansion valves. In this modification, by operating the inflow side adjustment valve (116) and the outflow side adjustment valve (117), the piston member (93) is moved to change the volume of the auxiliary space (91).

<< Other Embodiments >>
In each of the above embodiments, the expansion mechanism (60) of the compression / expansion unit (30) may be constituted by a scroll type fluid machine.

  As shown in FIG. 8, the expansion mechanism (60) of the present modification is provided with a fixed scroll (120) and a movable scroll (122). The fixed scroll (120) is formed with a fixed wrap (121). A movable side wrap (123) is formed on the movable scroll (122). The fixed side wrap (121) and the movable side wrap (123) are both formed in a spiral wall shape, and mesh with each other to form a plurality of expansion chambers (66a, 66b). Specifically, in the expansion mechanism (60), the space sandwiched between the inner side surface of the fixed side wrap (121) and the outer side surface of the movable side wrap (123) constitutes the A chamber (66a) as a fluid chamber. A space sandwiched between the outer side surface of the fixed side wrap (121) and the inner side surface of the movable side wrap (123) constitutes a B chamber (66b) as a fluid chamber.

  In the expansion mechanism (60) of this modification, both the inflow port (34) and the outflow port (35) are formed in the fixed scroll (120). The inflow port (34) is open near the inner peripheral end (winding start end) of the fixed wrap (121), and the A chamber (66a) and B formed on the innermost peripheral side. It is possible to communicate with the room (66b). The outflow port (35) opens near the outer peripheral side end (end of the winding end side) of the fixed side wrap (121), and the A chamber (66a) and the B chamber ( 66b).

  In the expansion mechanism (60) of this modification, for example, a cylinder space (90) is formed in the fixed scroll (120). As in the above embodiments, the cylinder space (90) is divided into the auxiliary space (91) and the drive space (92) by the piston member (93). The auxiliary space (91) communicates with the innermost chamber A (66a) through the first connection passage (96), and the innermost chamber B (through the second connection passage (97) ( 66b).

  As in the above embodiments, in the expansion mechanism (60) of this modification, the coil spring (94) is accommodated in the drive space (92), and this coil spring (94) is accommodated in the piston member (93). On the other hand, a force directed to the drive space (92) is applied. In addition, an oil circulation pipe (100) or a refrigerant circulation pipe (110) is connected to the drive space (92).

  In the expansion mechanism (60) of this modification, as in the above embodiments, when the refrigerating machine oil or liquid refrigerant, which is an incompressible fluid, flows into and out of the drive space (92), the piston member (93) It moves, thereby increasing or decreasing the volume of the auxiliary space (91). When the volume of the auxiliary space (91) changes, the volume of the high-pressure refrigerant that flows into the inflow port (34) of the expansion mechanism (60) changes in one inflow stroke.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for an expander connected to a refrigerant circuit that performs a refrigeration cycle.

It is a refrigerant circuit figure which shows schematic structure of the air conditioner of Embodiment 1. It is a longitudinal cross-sectional view which shows schematic structure of the compression / expansion unit of Embodiment 1. It is a cross-sectional view which shows the principal part of each rotary mechanism part of Embodiment 1 separately. FIG. 5 is a transverse cross-sectional view showing a state of each rotary mechanism portion at every 90 ° rotation angle of the shaft in the expansion mechanism of the first embodiment. It is a longitudinal cross-sectional view which shows schematic structure of the compression-expansion unit of the modification of Embodiment 1. It is a longitudinal cross-sectional view which shows schematic structure of the compression / expansion unit of Embodiment 2. It is a longitudinal cross-sectional view which shows schematic structure of the compression-expansion unit of the modification of Embodiment 2. It is a cross-sectional view which shows schematic structure of the expansion mechanism of other embodiment.

20 Refrigerant circuit
30 Compression / expansion unit (expander)
40 shaft (rotary axis)
50 Compression mechanism (compressor)
60 Expansion mechanism
66 Expansion chamber
66a Room A
66b Room B
72 First fluid chamber
91 Auxiliary space
92 Drive space
93 Piston member
94 Coil spring (elastic member)
100 Oil distribution piping
101 Oil inflow pipe (oil inflow passage)
102 Oil spill pipe (oil spill passage)
110 Refrigerant distribution piping
111 Refrigerant inlet pipe (refrigerant inlet passage)
112 Refrigerant outflow pipe (refrigerant outflow passage)

Claims (7)

An expander connected to a refrigerant circuit (20) for performing a refrigeration cycle,
While comprising an expansion mechanism (60) that is constituted by a positive displacement fluid machine that forms the fluid chamber (72) and in which the refrigerant expands in the fluid chamber (72),
The expansion mechanism (60) includes an auxiliary space (91) communicating with the fluid chamber (72), a driving space (92) filled with an incompressible fluid, and the auxiliary space (91). A movable piston member (93) for partitioning the drive space (92) is provided;
The auxiliary member is moved by supplying the incompressible fluid to the driving space (92) and discharging the incompressible fluid from the driving space (92) to move the piston member (93). An expander configured to change the volume of the space (91). In claim 1,
The expander characterized in that the incompressible fluid filling the drive space (92) is refrigeration oil existing in the refrigerant circuit (20). In claim 2,
Refrigeration oil stored in a portion of the refrigerant circuit (20) where high-pressure gas refrigerant discharged from the compressor (50) of the refrigerant circuit (20) is present is caused to flow into the drive space (92). An oil inflow passage (101),
An oil outflow passage (102) for flowing out the refrigeration oil in the drive space (92) to a portion of the refrigerant circuit (20) through which the low-pressure refrigerant sucked into the compressor (50) flows. An expander characterized by having In claim 1,
The expander characterized in that the incompressible fluid filling the drive space (92) is a liquid refrigerant existing in the refrigerant circuit (20). In claim 4,
A refrigerant inflow passage (111) for allowing the high-pressure liquid refrigerant before expansion flowing through a portion connected to the inflow side of the expansion mechanism (60) in the refrigerant circuit (20) to flow into the drive space (92);
Refrigerant outflow passage (112) for connecting the liquid refrigerant in the drive space (92) to the outflow side of the expansion mechanism (60) in the refrigerant circuit (20) and flowing out to the portion where the low-pressure refrigerant after expansion flows And an expander. In any one of Claims 1 thru | or 5,
An expander comprising an elastic member (94) for applying a force in the direction of the drive space (92) to the piston member (93). In any one of Claims 1 thru | or 6,
A compression mechanism (50) that is a fluid machine for compressing the refrigerant and that constitutes the compressor of the refrigerant circuit (20);
An expander comprising a rotation shaft (40) for connecting the compression mechanism (50) to the expansion mechanism (60).

Images