JP2009228568A - Refrigerating device and expander - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve power recovery efficiency by reducing the dead volume of an auxiliary suction path under a blocked condition, in an expansion mechanism introducing a refrigerant to a fluid chamber of the expansion mechanism through the auxiliary suction path. <P>SOLUTION: The auxiliary suction path 70 branching off of a suction side of a first fluid chamber 52 and connecting to a suction/expansion process position of the first fluid chamber 52 is formed in a first expansion mechanism 41. A valve element 83 capable of blocking a flow out opening part 75 of the auxiliary suction path 70 is provided in the first expansion mechanism 41. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus including an expansion mechanism that recovers the power of a refrigerant expanded in a fluid chamber, and an expander applied to the refrigeration apparatus.

  Conventionally, a refrigeration apparatus that performs a refrigeration cycle has been widely applied to air conditioners and the like. As this type of refrigeration apparatus, there is an apparatus in which an expansion mechanism is connected to a refrigerant circuit and the power of the refrigerant is recovered by the expansion mechanism.

  Patent Document 1 discloses this type of refrigeration apparatus. In the expansion mechanism of this refrigeration apparatus, the power recovered from the high-pressure refrigerant is transmitted to the compression mechanism via the drive shaft and used as drive power for the compression mechanism.

  By the way, since the refrigerant circuit is a closed circuit, the circulation amount of the refrigerant passing through the compression mechanism per unit time (corresponding to the mass flow rate, the same shall apply hereinafter) and the circulation amount of the refrigerant passing through the expansion mechanism must always match. I must. However, when the expansion mechanism is designed at a certain design specification point (for example, heating rating), when operated under conditions that deviate from the design specification point, the amount of circulation between the compression mechanism and the amount of circulation in the expansion mechanism is between. Excess or deficiency will occur. Specifically, for example, when the circulation rate between the compression mechanism and the expansion mechanism is matched at the time of heating rating, the optimum suction volume of the expansion mechanism is the heating rating at the cooling rating when the suction pressure of the compression mechanism increases. Since it becomes larger than the case of time, the refrigerant is insufficient and overexpansion occurs.

Therefore, in Patent Document 1, a communication pipe is connected to the expansion mechanism. One end of the communication pipe communicates with the main suction passage of the expansion mechanism, and the other end passes through the expansion mechanism and communicates with the suction / expansion process position of the fluid chamber. The communication pipe is provided with an electric valve outside the expansion mechanism. In the expansion mechanism, for example, under an operating condition in which the suction pressure of the compression mechanism becomes high, the motor-operated valve is opened to a predetermined opening, and the high-pressure refrigerant is introduced into the suction / expansion process position of the fluid chamber through the communication pipe. Thereby, since the pressure of the refrigerant | coolant of the outflow side of an expansion mechanism approaches the suction pressure of a compression mechanism, generation | occurrence | production of the overexpansion as mentioned above can be prevented.
JP 2004-197640 A

  In the expansion mechanism disclosed in Patent Document 1, when the suction pressure of the compression mechanism and the pressure of the refrigerant on the outflow side of the expansion mechanism are substantially equal, the refrigerant is expanded while the motor-operated valve is closed. However, when the motor-operated valve is in a closed state, the space from the motor-operated valve in the closed state to the fluid chamber becomes dead volume in the communication pipe, and the power recovery efficiency in the expansion mechanism may decrease. .

  This point will be described with reference to FIG. FIG. 13 is a PV diagram showing the relationship between the cylinder volume and the refrigerant pressure in the expansion mechanism. When the above dead volume is not formed in the communication pipe of the expansion mechanism, the pressure of the refrigerant and the cylinder volume change in a behavior such as point A → point B → point C → point D. That is, in the expansion mechanism, the volume of the fluid chamber is expanded from the point A to the point B, and the refrigerant is sucked into the fluid chamber (suction process). Next, from point B to point C, the volume of the fluid chamber further increases, and the refrigerant pressure gradually decreases (expansion process). Thereafter, the volume of the fluid chamber is reduced from point C to point D, and the decompressed refrigerant flows out of the fluid chamber (discharge process).

  On the other hand, when the above dead volume is formed in the communication pipe, for example, the refrigerant pressure and the cylinder in the behavior of point A → B ′ point → B1 ′ point → B2 ′ point → C point → D point. The volume changes. That is, in the suction / expansion process from the point A to the point C, the refrigerant sucked into the fluid chamber is expanded / depressurized due to the dead volume. As a result, when there is a dead volume, the power recovered by the expansion mechanism (that is, the area (work volume) surrounded by A to D) decreases compared to the case where there is no dead volume.

  As described above, in the expansion mechanism as disclosed in Patent Document 1, when the motor-operated valve is closed, a dead volume is formed and the power recovery efficiency is lowered. In particular, in Patent Document 1, since the motor-operated valve is disposed outside the expansion mechanism, the space (dead volume) from the motor-operated valve to the fluid chamber is relatively large. Therefore, in this expansion mechanism, the reduction in power recovery efficiency due to dead volume becomes even more remarkable.

  The present invention has been made in view of such a point, and an object of the present invention is to reduce the dead volume of the auxiliary suction passage that is in a closed state with respect to the expansion mechanism that introduces the refrigerant into the fluid chamber of the expansion mechanism through the auxiliary suction passage. It is to improve the power recovery efficiency.

  In the first invention, a fluid chamber (52) is formed between the first member (50) and the second member (51) that are relatively eccentrically rotated, and the fluid chamber (52) is sucked into the fluid chamber (52). A refrigeration apparatus provided with an expansion mechanism (41) for recovering the power of the refrigerant is assumed. The refrigeration apparatus has an auxiliary suction path (70) that branches from the suction side of the fluid chamber (52) and communicates with the suction / expansion process position of the fluid chamber (52) inside the expansion mechanism (41). An open / close member (83) that opens and closes the auxiliary suction path (70) is provided in the auxiliary suction path (70).

  In the expansion mechanism (41) of the first invention, the refrigerant expands in the fluid chamber (52) formed between the first member (50) and the second member (51). The power of the refrigerant expanded in the fluid chamber (52) is recovered as the rotational power of the first member (50) and the second member (51). An auxiliary suction path (70) branched from the suction side of the fluid chamber (52) is formed inside the expansion mechanism (41) of the present invention. Furthermore, an opening / closing member (83) is provided inside the auxiliary suction passage (70). Thereby, the flow rate of the refrigerant introduced into the suction / expansion process of the fluid chamber (52) can be adjusted by opening and closing the opening / closing member (83). Therefore, the refrigerant circulation amounts of the compression mechanism and the expansion mechanism (41) can be balanced, and the occurrence of overexpansion in the expansion mechanism (41) is prevented.

  Here, in the present invention, an auxiliary suction path (70) is formed inside the expansion mechanism (41), and an opening / closing member (83) is provided inside the auxiliary suction path (70). Therefore, compared with the case where the opening / closing member (motor-operated valve) is arranged outside the expansion mechanism as in Patent Document 1, the present invention is more closed to the fluid chamber (52) from the opening / closing member (83) in the closed state. The distance can be shortened. As a result, in the present invention, the dead volume formed in the auxiliary suction path (70) can be reduced.

  According to a second aspect of the present invention, in the refrigeration apparatus according to the first aspect, the open / close member (83) is arranged in a closed state so as to follow the inner wall of the fluid chamber (52). ) Is configured to be a valve body (83) that closes.

  In the second invention, the opening / closing member (83) is constituted by the valve body (83). The valve body (83) closes the outflow end (75) along the inner wall of the fluid chamber (52) when in the closed state in which the auxiliary suction path (70) is closed. Thereby, when the auxiliary suction path (70) is closed, a space (dead volume) is hardly formed between the valve body (83) and the fluid chamber (52).

  According to a third aspect of the present invention, in the refrigeration apparatus of the first or second aspect, the auxiliary suction passage (70) is branched between the suction side of the fluid chamber (52) and the inside of the expansion mechanism (41). It is characterized by this.

  In the third invention, the suction side of the fluid chamber (52) and the auxiliary suction path (70) are branched inside the expansion mechanism (41). That is, in the present invention, the auxiliary suction path (70) is formed inside the expansion mechanism (41) without providing a pipe branching from the suction side of the fluid chamber (52) outside the expansion mechanism (41).

  According to a fourth invention, in any one of the first to third inventions, the valve body (83) is disposed between the open / close positions of the auxiliary suction passage (70) in the expansion mechanism (41). A valve body chamber (80) for slidably accommodating is formed, and a refrigerant introduction path (26, 27, 28, 77) for introducing a refrigerant to the back side of the valve body (83) in the valve body chamber (80), A pressure control mechanism (19, 20) for controlling the pressure of the refrigerant in the refrigerant introduction path (26, 27, 28, 77) is further provided.

  In 4th invention, a valve body (83) is accommodated in the valve body chamber (80) formed in the inside of an expansion mechanism (41). Refrigerant from the refrigerant introduction path (26, 27, 28, 77) is introduced to the back side of the valve body (83). On the other hand, the pressure of the refrigerant from the fluid chamber (52) acts on the distal end side of the valve body (83). When the pressure of the refrigerant in the refrigerant introduction path (26, 27, 28, 77) is controlled to be low by the pressure control mechanism (19, 20), the valve body (83) is moved to the rear side by the pressure of the refrigerant from the fluid chamber (52). Displace. As a result, the valve body (83) can be displaced to the open position. Further, when the pressure of the refrigerant in the refrigerant introduction path (26, 27, 28, 77) is controlled to be high by the pressure control mechanism (19, 20), the pressure of the refrigerant from the refrigerant introduction path (26, 27, 28, 77) The valve body (83) is displaced to the tip side. As a result, the valve body (83) can be displaced to the closed position.

  According to a fifth aspect of the present invention, in the refrigeration apparatus of the fourth aspect, the refrigerant introduction path (26, 27, 28, 77) has one end communicating with the outflow side of the expansion mechanism (41) and the other end of the valve body. Low pressure side introduction path (27) connected to the chamber (80), and high pressure side introduction path (28,77) whose one end communicates with the suction side of the expansion mechanism (41) and the other end communicates with the valve body chamber (80) The pressure control mechanism includes an opening degree adjustment valve (19, 20) that adjusts the opening degree of one or both of the low pressure side introduction path (27) and the high pressure side introduction path (28, 77). ).

  In the fifth invention, the opening degree of either one or both of the high pressure side introduction path (28, 77) and the low pressure side introduction path (27) is adjusted by the opening degree adjustment valve (19, 20) as a pressure control mechanism. Is done. As a result, the pressure of the refrigerant on the back side of the valve body (83) can be adjusted as appropriate, and the valve body (83) can be displaced between the open position and the closed position.

  According to a sixth aspect of the present invention, in the refrigeration apparatus of the fifth aspect, the on-off control valve is composed of an on-off valve (19) for opening and closing the low-pressure side introduction path (27), and the high-pressure side introduction path (28, 77). ) Is provided with a throttle portion (90) that provides resistance to the flow of the refrigerant.

  In 6th invention, a low pressure refrigerant | coolant is introduce | transduced into the back side of a valve body (83) by opening the on-off valve (19) as an opening degree adjustment valve. As a result, the valve body (83) is displaced to the open position by the pressure of the fluid chamber (52). Here, since the throttle part (90) is provided in the high-pressure side introduction path (28, 77), it is possible to minimize the introduction of the high-pressure refrigerant into the valve body chamber (80). . On the other hand, when the on-off valve (19) in the low pressure side introduction path (27) is closed, the high pressure refrigerant in the high pressure side introduction path (28, 77) gradually flows to the valve body chamber (80) through the throttle portion (90), A high-pressure refrigerant acts on the back side of the valve body (83). As a result, the valve body (83) can be displaced to the closed position by the high-pressure refrigerant.

  According to a seventh invention, in the refrigeration apparatus of the fifth invention, the high-pressure side introduction path (77) has one end communicating with the auxiliary suction path (70) and the other end connected with the valve body chamber (80). It is formed inside the expansion mechanism (41).

  In the seventh invention, the high-pressure side introduction path (77) is formed inside the expansion mechanism (41). The high-pressure refrigerant in the auxiliary suction passage (70) is introduced into the high-pressure side introduction passage (77), and this high-pressure refrigerant acts on the back side of the valve body (83) in the valve body chamber (80).

  In an eighth invention according to any one of the fourth to seventh inventions, a biasing means (87) for biasing the valve body (83) toward the closed position in the valve body chamber (80). Is provided.

  In the eighth invention, the urging means (87) urges the valve body (83) to the closed position where the outflow end (75) of the auxiliary suction passage (70) is closed. For this reason, even if the internal pressure of the fluid chamber (52) changes, the valve body (83) is prevented from swinging back and forth. As a result, the generation of dead volume at the outflow end (75) of the auxiliary suction path (70) is also reliably prevented.

  According to a ninth invention, in any one of the first to eighth refrigeration apparatuses, the expansion mechanism is rotatably accommodated in the cylinder (50) as the first member and the cylinder (50). It is comprised by the rotary type expansion mechanism (41) which has the piston (51) as said 2nd member, and the obstruction | occlusion member (43,44) which obstruct | occludes the edge part of the said cylinder (50). Is.

  In the ninth invention, the expansion mechanism is a so-called rotary expansion mechanism.

  According to a tenth aspect of the invention, in the refrigeration apparatus of the ninth aspect, the auxiliary suction passage (70) includes an arc-shaped passage (72) formed in the circumferential direction along the cylinder (50). It is characterized by this.

  In the expansion mechanism (41) of the tenth aspect of the invention, an arcuate channel (72) extending in the circumferential direction along the cylinder (50) is formed, and the arcuate channel (72) is formed as the auxiliary suction channel (70). Constituting at least a part of Thus, by forming the arc-shaped flow path (72) along the cylinder (50), it is possible to avoid the auxiliary suction path (70) from interfering with other members.

  An eleventh aspect of the invention is the refrigeration apparatus of the ninth or tenth aspect of the invention, wherein at least a part of the auxiliary suction path (70) is one of the cylinder (50) and the closing member (43, 44) or It is characterized by comprising groove portions (71, 72, 73) formed on both end faces.

  In the eleventh invention, a groove (71, 72, 73) is formed on one or both end surfaces of the cylinder (50) and the closing member (43, 44), and the groove (71, 72, 73) is formed. It constitutes a part of the auxiliary suction path (70). Thereby, the auxiliary suction path (70) can be processed / formed relatively easily inside the expansion mechanism (41).

  A twelfth aspect of the invention is the refrigeration apparatus according to any one of the first to eleventh aspects of the invention, wherein the auxiliary suction passage (70) is branched into a plurality of branch passages (the branch passage branching from the suction side of the fluid chamber (52)) 70a, 70b) and one confluence channel with one end connected to the outflow end of a plurality of branch channels (70a, 70b) and the other end communicating with the suction / expansion process position of the fluid chamber (52) 74), and the opening and closing member (83) is configured to open and close the merging channel (74).

  The auxiliary suction passage (70) of the twelfth aspect of the invention has a plurality of branch passages (70a, 70b) and one merging passage (74). When the opening / closing member (83) opens the merging channel (74), the refrigerant on the suction side of the fluid chamber (52) flows through the branch channels (70a, 70b) and then passes through the merging channel (74). It joins and is introduced into the suction / expansion process position of the fluid chamber (52). By forming a plurality of branch channels (70a, 70b) in this way, the pressure loss of the refrigerant in the auxiliary suction channel (70) is reduced. As a result, it is possible to avoid a decrease in the pressure of the refrigerant introduced from the auxiliary suction path (70) into the fluid chamber (52).

  In a thirteenth aspect of the present invention, a fluid chamber (52) is formed between the first member (50) and the second member (51) that are relatively eccentrically rotated, and the fluid chamber (52) is sucked into the fluid chamber (52). An expander including an expansion mechanism (41) for recovering the power of the refrigerant is assumed. The refrigeration apparatus includes an auxiliary suction path (70) that branches from the suction side of the fluid chamber (52) into the expansion mechanism (41) and communicates with the suction / expansion process position of the fluid chamber (52). And an opening / closing member (83) for opening and closing the auxiliary suction passage (70) is provided in the auxiliary suction passage (70).

  In the thirteenth invention, an expander applied to the refrigeration apparatus of the first invention can be configured.

  A fourteenth invention is the expander of the thirteenth invention, wherein the opening / closing member (83) closes the outflow end of the auxiliary suction passage (70) so as to follow the inner wall of the fluid chamber (52) in the closed state. It is characterized by comprising a valve body (83).

  In the fourteenth invention, an expander applied to the refrigeration apparatus of the second invention can be configured.

  In the first invention, the auxiliary suction path (70) is formed inside the expansion mechanism (41), and the opening / closing member (83) is provided in the auxiliary suction path (70). Thereby, compared with the case where an opening / closing member is provided outside the expansion mechanism (41), the distance from the outflow opening of the auxiliary suction passage (70) to the fluid chamber (52) can be shortened. The space (dead volume) between the opening / closing member (83) and the fluid chamber (52) can be reduced. As a result, the refrigerant in the fluid chamber (52) can be prevented from being depressurized due to the dead volume, and the power recovery efficiency of the expansion mechanism (41) can be improved.

  In particular, in the second invention, the outflow end (75) of the auxiliary suction passage (70) is closed so that the valve body (83) in the closed state is along the inner wall of the fluid chamber (52). Thereby, the dead volume between the valve body (83) in the closed state and the fluid chamber (52) can be almost eliminated, and the power recovery efficiency of the expansion mechanism (41) can be further improved.

  In the third aspect of the invention, the suction side of the fluid chamber (52) and the auxiliary suction path (70) are branched inside the expansion mechanism (41). Thus, the auxiliary suction passage (70) can be formed inside the expansion mechanism (41) without providing a branching pipe outside the expansion mechanism (41), thereby reducing the number of parts and the expansion mechanism (41 ) Can be made compact.

  In the fourth invention, the valve body (83) is displaced between the open position and the closed position by controlling the pressure of the refrigerant on the back side of the valve body (83). Thereby, the valve body (83) inside the expansion mechanism (41) can be opened and closed with a relatively simple structure.

  In particular, according to the fifth aspect, the high pressure side introduction path (28, 77) connected to the inflow side of the expansion mechanism (41) and the low pressure side introduction path (27) connected to the outflow side of the expansion mechanism (41). By adjusting the opening with the opening adjusting valve (19, 20), the pressure of the refrigerant acting on the back surface of the valve element (83) can be easily and quickly changed.

  According to the sixth aspect of the invention, the on-off valve (19) is provided in the low-pressure side introduction path (27), and the throttle part (90) is provided in the low-pressure side introduction path (27), thereby using two on-off valves. The valve body (83) can be opened and closed without any trouble.

  Further, according to the seventh invention, since the high-pressure side introduction passage (77) is formed inside the expansion mechanism (41) so as to communicate with the auxiliary suction passage (70), the outside of the expansion mechanism (41) There is no need to provide piping or the like for configuring the high-pressure side introduction path. Therefore, the expansion mechanism (41) can be made compact and simple.

  Further, according to the eighth invention, since the valve body (83) is urged toward the closed position by the urging means (87), the valve body (83) according to the change in the internal pressure of the fluid chamber (52). ) Can be suppressed, and generation of dead volume and vibration due to this can be prevented.

  According to the ninth aspect, in the rotary type expansion mechanism (41), it is possible to prevent the dead volume from being generated in the closed auxiliary suction passage (70) and to improve the power recovery efficiency.

  Further, according to the tenth invention, the arcuate channel (72) extending in the circumferential direction along the cylinder (50) is used as at least a part of the auxiliary suction channel (70). 70) can be prevented from interfering with other members, and the outflow end (75) of the auxiliary suction passage (70) can be formed at a desired angular position.

  According to the eleventh aspect of the present invention, the groove (71, 72, 73) on the end surface of the cylinder (50) or the closing member (43, 44) is used as at least a part of the auxiliary suction passage (70). The auxiliary suction path (70) can be formed inside the expansion mechanism (41) by simple processing.

  According to the twelfth aspect, since a part of the auxiliary suction passage (70) is constituted by the plurality of branch passages (70a, 70b), the pressure loss of the auxiliary suction passage (70) can be reduced. Thereby, it can suppress that the pressure of the fluid introduce | transduced into a fluid chamber (52) from an auxiliary | assistant suction path (70) falls, and can increase the motive power of the refrigerant | coolant collect | recovered by a fluid chamber (52). .

  According to the thirteenth invention, an expander that exhibits the effects of the first invention can be provided, and according to the fourteenth invention, an expander that exhibits the effects of the second invention can be provided.

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

  In the present embodiment, the refrigeration apparatus according to the present invention constitutes an air conditioner (10). The air conditioner (10) is configured to switch between indoor cooling and heating.

<Overall configuration of air conditioner>
As shown in FIG. 1, the air conditioner (10) includes a refrigerant circuit (11). The refrigerant circuit (11) constitutes a closed circuit in which the refrigerant circulates and performs a refrigeration cycle. The refrigerant circuit (11) is filled with carbon dioxide (CO ₂ ) as a refrigerant. That is, in the refrigerant circuit (11), a so-called supercritical cycle is performed in which carbon dioxide is compressed to a critical pressure or higher. The refrigerant circuit (11) includes a compression / expansion unit (30), an outdoor heat exchanger (12), an indoor heat exchanger (13), a four-way switching valve (14), a bridge circuit (15), and a pre-expansion valve (17 ) And are provided.

  The compression / expansion unit (30) includes a casing (31) formed in a vertically long cylindrical closed container shape. In the casing (31), a compression mechanism (32), an electric motor (33), and a two-stage expansion unit (40) are provided in order from the lower part to the upper part. The compression / expansion unit (30) is provided with an output shaft (34) for connecting the compression mechanism (32), the electric motor (33), and the two-stage expansion unit (40).

  The compression mechanism (32) is a rotary positive displacement compressor, and is configured as a so-called oscillating piston type. The refrigerant compressed by the compression mechanism (32) is introduced into the casing (31) through the discharge port. That is, the compression / expansion unit (30) has a so-called high-pressure dome type in which the inside of the casing (31) is filled with the high-pressure refrigerant.

  The electric motor (33) includes a stator part (35) fixed to the inner peripheral surface of the casing (31), and a rotor part (36) that is located inside the stator part (35) and is connected to the output shaft (34). have. The rotation speed of the electric motor (33) is variable by adjusting the output frequency. That is, the compression / expansion unit (30) is configured as an inverter.

  The two-stage expansion unit (40) is a so-called two-cylinder expansion unit, and includes a first expansion mechanism (41) and a second expansion mechanism (42). The first expansion mechanism (41) and the second expansion mechanism (42) are rotary positive displacement expanders, and are configured as so-called oscillating piston types. The first expansion mechanism (41) and the second expansion mechanism (42) are connected in series, the first expansion mechanism (41) is the upstream expansion mechanism, and the second expansion mechanism (42) is the downstream expansion mechanism. Is configured. The displacement volume of the first expansion mechanism (41) is smaller than the displacement volume of the second expansion mechanism (42). The first expansion mechanism (41) and the second expansion mechanism (42) are connected to the output shaft (34). Details of the two-stage expansion unit (40) will be described later.

  The compression / expansion unit (30) includes a suction pipe (21), a discharge pipe (22), an inflow pipe (23), and an outflow pipe (24). The suction pipe (21) passes through the casing (31) and is directly connected to the suction side of the compression mechanism (32). The discharge pipe (22) passes through the casing (31) and opens into the casing (31). The inflow pipe (23) passes through the casing (31) and is directly connected to the suction side (inflow side) of the first expansion mechanism (41). The outflow pipe (24) passes through the casing (31) and is directly connected to the discharge side (outflow side) of the second expansion mechanism (42).

  Both the outdoor heat exchanger (12) and the indoor heat exchanger (13) constitute a cross fin type fin-and-tube heat exchanger. The four-way switching valve (14) has first to fourth ports. The first port communicates with the suction pipe (21), and the second port communicates with the discharge pipe (22). The third port communicates with one end of the outdoor heat exchanger (12), and the fourth port communicates with one end of the indoor heat exchanger (13). The four-way switching valve (14) includes a state in which the first port and the fourth port communicate with each other and a state in which the second port and the third port communicate with each other (state indicated by a solid line in FIG. 1), The 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 bridge circuit (15) is configured by connecting four pipes each having a check valve (16) in a bridge shape. The bridge circuit (15) always causes the refrigerant to flow in the same direction to the two-stage expansion unit (40) even if the refrigerant circulation direction is changed in accordance with the switching of the four-way switching valve (14). A four-way switching valve may be provided instead of the bridge circuit (15). The pre-expansion valve (17) is provided in a pipe connecting the bridge circuit (15) and the inflow pipe (23). The pre-expansion valve (17) constitutes a flow rate adjustment valve whose opening degree can be adjusted.

  A bypass pipe (25), a main introduction pipe (26), a low pressure introduction pipe (27), and a high pressure introduction pipe (28) are connected to the refrigerant circuit (11). The bypass pipe (25) has one end connected to the pipe between the pre-expansion valve (17) and the inflow pipe (23) and the other end connected to the pipe between the bridge circuit (15) and the outflow pipe (24). Connected. A bypass valve (18) is provided in the bypass pipe (25). The bypass valve (18) constitutes a flow rate control valve whose opening degree can be adjusted.

  The terminal end of the main introduction pipe (26) is connected to a valve body chamber (details will be described later) of the first expansion mechanism (41). The starting ends of the main introduction pipe (26) are connected to the ends of the low pressure introduction pipe (27) and the high pressure introduction pipe (28), respectively. The starting end of the low pressure introduction pipe (27) is connected to the outflow side of the two-stage expansion unit (40) (that is, the low pressure line of the refrigerant circuit (11)). That is, the low pressure introduction pipe (27) constitutes a low pressure side introduction path communicating with the outflow side of the two-stage expansion unit (40). The starting end of the high pressure introduction pipe (28) is connected to the suction side of the two-stage expansion unit (40) (that is, the high pressure line of the refrigerant circuit (11)). That is, the high pressure introduction pipe (28) constitutes a high pressure side introduction path that communicates with the suction side of the two-stage expansion unit (40). The low pressure introduction pipe (27) is provided with a low pressure introduction valve (19), and the high pressure introduction pipe (28) is provided with a high pressure introduction valve (20). The low pressure introduction valve (19) and the high pressure introduction valve (20) constitute an on-off valve (opening control valve) that can be freely opened and closed. Note that the low pressure introduction valve (19) and the high pressure introduction valve (20) do not necessarily have to be switched between two stages of opening and closing, and are flow rate adjustment valves (motorized valves) capable of fine adjustment of the opening degree. May be.

<Configuration of two-stage expansion unit>
As shown in FIG. 2, the above-described two-stage expansion unit (40) is provided on the compression / expansion unit (30). The two-stage expansion unit (40) includes the first expansion mechanism (41), the second expansion mechanism (42), the front head (43), the intermediate plate (44), and the rear head (45). In the two-stage expansion unit (40), from the lower end to the upper end of the output shaft (34), the front head (43), the first expansion mechanism (41), the intermediate plate (44), the second expansion mechanism (42), And the rear head (45) is arranged and laminated in order.

  The first expansion mechanism (41) has a first cylinder (50) and a first piston (51). The second expansion mechanism (42) has a second cylinder (60) and a second piston (61). Each expansion mechanism (41, 42) is configured such that the piston (51, 61) as the second member rotates relatively eccentrically with respect to the cylinder (50, 60) as the first member.

  The cylinders (50, 60) are formed in a substantially cylindrical shape with both upper and lower ends open. The inner diameter and thickness of the first cylinder (50) are shorter than the inner diameter and thickness of the second cylinder (60). The first cylinder (50) has a lower end surface closed by the front head (43) and an upper end surface closed by the intermediate plate (44). The second cylinder (60) has a lower end surface closed by the intermediate plate (44) and an upper end surface closed by the rear head (45). That is, the front head (43), the intermediate plate (44), and the rear head (45) constitute a closing member that closes the end of the cylinder (50, 60). Further, these closing members (43, 44, 45) and the cylinders (50, 60) constitute a fixing member fixed to the casing (31).

  A first piston (51) is accommodated in the first cylinder (50), and a first fluid chamber (52) is defined between the first cylinder (50) and the first piston (51). Yes. A second piston (61) is accommodated in the second cylinder (60), and a second fluid chamber (62) is defined between the second cylinder (60) and the second piston (61). Yes. The pistons (51, 61) are formed in a cylindrical shape or an annular shape. The inner diameter, outer diameter, and thickness of the first piston (51) are shorter than the inner diameter, outer diameter, and thickness of the second piston (51). Inside the first piston (51) is a first eccentric part (34a) of the output shaft (34), and inside the second piston (61) is a second eccentric part (34b) of the output shaft (34). Are fitted inside. The eccentric parts (34a, 34b) constitute the crankshaft of the piston (51, 61). The amount of eccentricity of the first eccentric portion (34a) with respect to the axis of the output shaft (34) is smaller than the amount of eccentricity of the second eccentric portion (34b).

  As shown in FIG. 3, the first expansion mechanism (41) has a first blade (53) and a pair of first bushes (54), and the second expansion mechanism (42) has a second blade (63) and a pair. The second bush (64) is provided. The blades (53, 63) are formed in a plate shape extending radially outward from the outer peripheral surface of the piston (51, 61). The pair of bushes (54, 64) are fitted in bush grooves (55, 65) formed in the cylinder (50, 60). The pair of bushes (56, 64) each have a flat surface portion and an arc portion, and are disposed so that the flat surface portions face each other. The blades (53, 63) are sandwiched between the pair of bushes (56, 64). The bush (56, 64) is rotatable with respect to the cylinder (50, 60), and the blade (53, 63) is movable with respect to the bush (54, 64). As a result, the piston (51, 61) integrated with the blade (53, 63) is allowed to rotate (revolve) while sliding on the inner wall of the cylinder (50, 60).

  The outflow end of the main suction passage (46) is opened in the first fluid chamber (52) of the first cylinder (50). The main suction passage (46) is formed by extending the intermediate plate (44) in the radial direction, and the inflow pipe (23) is connected to the inflow end side thereof (see FIG. 2). The first fluid chamber (52) of the first cylinder (50) has an inflow end of the communication path (47). The communication path (47) is formed by extending the intermediate plate (44) obliquely in the axial direction. In the first expansion mechanism (41), the outflow end of the main suction passage (46) and the inflow end of the communication passage (47) are arranged so as to be close to each other while being blocked by the first blade (53).

  The outflow end of the communication path (47) is open in the second fluid chamber (62) of the second cylinder (60). Further, the inflow end of the outflow passage (48) is opened in the second fluid chamber (62) of the second cylinder (60). The outflow passage (48) is formed by extending the second cylinder (60) in the radial direction, and the outflow pipe (24) is connected to the outflow end side (see FIG. 2). In the second expansion mechanism (42), the outflow end of the communication passage (47) and the inflow end of the outflow passage (48) are arranged so as to be close to each other while being blocked by the second blade (63).

  The first fluid chamber (52) is partitioned into two spaces by the first blade (53). In FIG. 3, the space partitioned on the right side of the first blade (53) constitutes a high pressure chamber (52a) communicating with the main suction passage (46), and the space partitioned on the left side is connected with the communication passage (47). A first expansion chamber (52b) that communicates is configured. The second fluid chamber (62) is partitioned into two spaces by the second blade (63). In FIG. 3, the space partitioned on the right side of the second blade (63) constitutes the second expansion chamber (62a) communicating with the communication passage (47), and the space partitioned on the left side is the outflow passage (48). Constitutes a low pressure chamber (62b) communicating with the

  In the present embodiment, an auxiliary suction path (70) is formed inside the first expansion mechanism (41). The auxiliary suction path (70) branches from the suction side of the first fluid chamber (52) and communicates with the first fluid chamber (52).

  As shown in FIG. 2 or FIG. 3, the auxiliary suction path (70) is constituted by first to fourth flow paths (71, 72, 73, 74). The first flow path (71) is formed by extending the intermediate plate (44) in the axial direction so that the start end is connected to the main suction path (46) and the other end faces the upper end surface of the first cylinder (50). Has been. That is, the main suction path (46) and the auxiliary suction path (70) are branched inside the first expansion mechanism (41). The first flow path (71) is constituted by a groove formed on the lower end surface of the intermediate plate (44). The second channel (72) has a start end connected to the first channel (71), and extends in the circumferential direction on the upper end surface of the first cylinder (50). That is, the second flow path (72) forms an arc-shaped flow path formed in the circumferential direction along the cylinder (50). The third channel (73) is formed such that its start end is connected to the end of the second channel (72) and extends in the axial direction toward the inside of the first cylinder (50). The 2nd channel (72) and the 3rd channel (73) are constituted by the slot formed in the upper end surface of the 1st cylinder (50). The fourth flow path (74) is connected to the end of the third flow path (73) at the start end, and the inside of the first cylinder (50) has a diameter so that the end opens to the first fluid chamber (52). It extends in the direction.

  The auxiliary suction passage (70) configured as described above has an outflow end opened to a suction / expansion process position of the first fluid chamber (52). That is, the outflow opening (75) of the auxiliary suction path (70) can communicate with the outflow end of the main suction path (46) via the high pressure chamber (52a) during the rotation of the first piston (51). In addition, the angular position is set so that it can communicate with the inflow end of the communication passage (47) via the first expansion chamber (52b).

  Specifically, in the present embodiment, the angular position of the outflow opening (75) of the auxiliary suction passage (70) when the first blade (53) to the first bush (54) are used as a reference with an angular position of 0 degree. Is set at about 220 ° in the direction of rotation. The angular position of the outflow opening (75) is not limited to this, and is arbitrarily set according to the operating conditions of the air conditioner (10).

  In the present embodiment, the valve body chamber (80) is also formed inside the first expansion mechanism (41). Specifically, the first cylinder (50) is formed with a bulging portion (57) that bulges radially from the outer peripheral surface thereof, and the valve body chamber (80) is formed in the bulging portion (57). Has been. The valve body chamber (80) is comprised by the large diameter cylinder part (81) and the small diameter cylinder part (82). The large-diameter cylindrical portion (81) is formed so as to extend in the radial direction inside the bulging portion (57) so that one end opens at the tip of the bulging portion (57). The outflow end portion of the main introduction pipe (26) is fitted into and connected to the opening on one end side of the large diameter cylindrical portion (81). The small diameter cylindrical portion (82) is formed with a smaller diameter than the large diameter cylindrical portion (81), and one end thereof is connected to the other end of the large diameter cylindrical portion (81). The small diameter cylindrical portion (82) is formed to extend in the radial direction, and the other end communicates with the fourth flow path (74). Further, the inner diameter of the small diameter cylindrical portion (82) is substantially equal to the inner diameter of the fourth flow path (74).

  A valve body (83) is accommodated in the valve body chamber (80). The valve body (83) constitutes an opening / closing member for opening / closing the auxiliary suction passage (70). The valve body (83) includes a large diameter portion (84) and a small diameter portion (85). The large-diameter portion (84) and the small-diameter portion (85) are each formed in a columnar shape, the large-diameter portion (84) is fitted into the large-diameter cylindrical portion (81), and the small-diameter portion (85) is small-diameter cylindrical portion ( 82). The valve body (83) is configured to advance and retract in the axial direction in the valve body chamber (80). Thereby, the valve body (83) communicates the third flow path (73) and the fourth flow path (74) to open the auxiliary suction path (70) (see FIGS. 2 and 3). The third flow path (73) and the fourth flow path (74) are blocked and can be displaced to a closed position (see FIG. 4) where the auxiliary suction path (70) is closed. Here, in the closed position (closed state), the valve body (83) is such that the tip of the small diameter portion (85) is along the inner peripheral surface of the first cylinder (50) (the inner wall of the first fluid chamber (52)). The outflow opening (75) of the auxiliary suction passage (70) is closed. That is, when the valve body (83) is displaced to a position (closed position) where the large diameter portion (84) contacts the other end portion of the large diameter cylindrical portion (81), the tip surface of the small diameter portion (85) The length of the small-diameter portion (85) is set so as to be substantially coincident (or slightly depressed) with the inner peripheral surface of the first fluid chamber (52). Note that an arc-shaped recess having an arc radius that is the same as the radius of the inner peripheral surface of the first cylinder (50) may be formed on the tip surface of the small diameter portion (85).

  The valve body chamber (80) accommodates a spring member (87) on the back side of the valve body (83). One end of the spring member (87) is in contact with or connected to the outflow end portion of the main introduction pipe (26), and the other end is in contact with or connected to the large diameter portion (84) of the valve body (83). The spring member (87) biases the valve body (83) toward the radially inner side of the first cylinder (50). That is, the spring member (87) constitutes a biasing means that biases the valve body (83) toward the closed position.

  In the valve body chamber (80), the refrigerant can be introduced from the main introduction pipe (26) toward the back side of the valve body (83). Specifically, the valve body chamber (80) includes a low-pressure refrigerant from the low-pressure introduction pipe (27) (that is, a refrigerant on the discharge side of the two-stage expansion unit (40)) and a high-pressure introduction pipe (28). The high-pressure refrigerant (that is, the refrigerant on the suction side of the two-stage expansion unit (40)) is introduced through the main introduction pipe (26) (see FIG. 1). That is, the main introduction pipe (26), the low pressure introduction pipe (27), and the high pressure introduction pipe (28) constitute a refrigerant introduction path for introducing refrigerant to the back side of the valve body (83) in the valve body chamber (80). is doing.

  In addition, the low pressure refrigerant and the high pressure refrigerant are selectively introduced into the valve body chamber (80) by switching the low pressure introduction valve (19) and the high pressure introduction valve (20) described above. Specifically, when the low pressure introduction valve (19) of the low pressure introduction pipe (27) is opened and the high pressure introduction valve (20) of the high pressure introduction pipe (28) is closed, the low pressure line and valve body chamber of the refrigerant circuit (11) (80) communicates and the valve body chamber (80) becomes a low pressure atmosphere. Thereby, the valve body (83) is displaced to the open position by the internal pressure of the first fluid chamber (52). On the other hand, when the low pressure introduction valve (19) of the low pressure introduction pipe (27) is closed and the high pressure introduction valve (20) of the high pressure introduction pipe (28) is opened, the high pressure line of the refrigerant circuit (11) and the valve body chamber (80 ) And the valve body chamber (80) becomes a high pressure atmosphere. As a result, the valve body (83) is biased by the spring member (87) and displaced to the open position. As described above, the low pressure introduction valve (19), the high pressure introduction valve (20), and the refrigerant introduction passage (26, 27, 28) are pressure control mechanisms that control the pressure of the refrigerant on the back side of the valve body (83). Is configured.

-Operation of the air conditioner-
First, the basic operation of the air conditioner (10) will be described. In the air conditioner (10), the cooling operation and the heating operation are switched according to the setting of the four-way switching valve (14).

<Cooling operation>
During the cooling operation, the four-way switching valve (14) is set to the state shown by the solid line in FIG. When the motor (33) of the compression / expansion unit (30) is energized in this state, a refrigeration cycle is performed in which the outdoor heat exchanger (12) serves as a radiator and the indoor heat exchanger (13) serves as an evaporator.

  The refrigerant compressed by the compression mechanism (32) is discharged into the casing (31) of the compression / expansion unit (30). The high-pressure refrigerant in the casing (31) flows through the outdoor heat exchanger (12) via the discharge pipe (22). In the outdoor heat exchanger (12), the refrigerant radiates heat to the outdoor air.

  The high-pressure refrigerant radiated by the outdoor heat exchanger (12) is sucked into the two-stage expansion unit (40) through the inflow pipe (23). In the two-stage expansion unit (40), the high-pressure refrigerant expands and power is recovered from the high-pressure refrigerant. The low-pressure refrigerant after expansion flows through the indoor heat exchanger (13) via the outflow pipe (24). In the indoor heat exchanger (13), the refrigerant absorbs heat from the room air, and the room air is cooled. The refrigerant evaporated in the indoor heat exchanger (13) is sucked into the compression mechanism (32) through the suction pipe (21) and compressed again.

<Heating operation>
During the heating operation, the four-way selector valve (14) is set to the state indicated by the broken line in FIG. When the motor (33) of the compression / expansion unit (30) is energized in this state, a refrigeration cycle is performed in which the indoor heat exchanger (13) serves as a radiator and the outdoor heat exchanger (12) serves as an evaporator.

  The refrigerant compressed by the compression mechanism (32) is discharged into the casing (31) of the compression / expansion unit (30). The high-pressure refrigerant in the casing (31) flows through the indoor heat exchanger (13) via the discharge pipe (22). In the indoor heat exchanger (13), the refrigerant dissipates heat to the room air, and the room air is heated.

  The high-pressure refrigerant radiated by the indoor heat exchanger (13) is sucked into the two-stage expansion unit (40) through the inflow pipe (23). In the two-stage expansion unit (40), the high-pressure refrigerant expands and power is recovered from the high-pressure refrigerant. The low-pressure refrigerant after expansion flows through the outdoor heat exchanger (12) via the outflow pipe (24). In the outdoor heat exchanger (12), the refrigerant absorbs heat from the outdoor air and evaporates. The refrigerant evaporated in the outdoor heat exchanger (12) is sucked into the compression mechanism (32) through the suction pipe (21) and compressed again.

-Operation of the 2-stage expansion unit-
Next, the operation of the two-stage expansion unit (40) will be described. In the two-stage expansion unit (40), the first operation and the second operation can be switched according to the open / close state of the low pressure introduction valve (19) and the high pressure introduction valve (20). The first operation and the second operation are appropriately switched according to switching between the cooling operation and the heating operation, or a change in the outside air temperature.

<First operation>
In the first operation, the low pressure introduction valve (19) of the refrigerant circuit (11) is closed and the high pressure introduction valve (20) is opened. Thereby, as above-mentioned, the back side of the valve body (83) in a valve body chamber (80) becomes high-pressure atmosphere. For this reason, the pressure on the back surface side of the valve body (83) is equal to or higher than the pressure on the distal end side (first fluid chamber (52) side) of the valve body (83). Accordingly, the valve body (83) is displaced toward the inside in the radial direction of the valve body chamber (80) while being urged by the spring member (87). As a result, the large-diameter portion (84) of the valve body (83) is held in contact with the small-diameter cylindrical portion (82) (see FIGS. 4 and 5). When the valve body (83) is displaced to the closed position in this way, the fourth flow path (74) of the auxiliary suction path (70) is almost completely closed.

  In such a state, in the two-stage expansion unit (40), the process of sucking the refrigerant (suction process), the process of expanding the refrigerant (expansion process), and the process of discharging the refrigerant (discharge process) are sequentially repeated. It is.

  In the suction process, the high-pressure refrigerant is sucked into the first fluid chamber (52) of the first expansion mechanism (41). Specifically, in the first expansion mechanism (41), when the rotation angle of the eccentric part (34a, 34b) is slightly rotated from the state of 0 ° (the state shown in FIG. 5A), the first piston (51) The first cylinder (50) and the first cylinder (50) come into contact with each other through the outflow opening of the main suction passage (46), and high-pressure refrigerant begins to flow from the main suction passage (46) into the high-pressure chamber (52a). Thereafter, as the rotation angle of the eccentric portions (34a, 34b) gradually increases to 90 ° (FIG. 5B), 180 ° (FIG. 5C), and 270 ° (FIG. 5D), High-pressure refrigerant flows into the high-pressure chamber (52a). The high-pressure refrigerant flows into the high-pressure chamber (52a) from the main suction passage (46) until the rotation angle of the eccentric portions (34a, 34b) reaches about 360 ° (the outflow opening of the main suction passage (46) is closed). Continue). Further, in the suction process of the first operation, the auxiliary suction path (70) is closed by the valve body (83) as described above. Therefore, no refrigerant is introduced from the auxiliary suction passage (70) into the high-pressure chamber (52a) during the suction process.

  In the next expansion process, the refrigerant expands in the first fluid chamber (52) and the second fluid chamber (62). Specifically, in the first expansion mechanism (41), when the rotation angle of the eccentric part (34a, 34b) is slightly rotated from a state of 360 °, the high-pressure chamber (52a) partitioned from the main suction path (46) The high pressure chamber (52a) becomes the first expansion chamber (52b) in communication with the inflow opening of the communication passage (47). Further, the first expansion chamber (52b) communicates with the second expansion chamber (62a) of the second expansion mechanism (42) via the communication path (47). As the rotation angle of the eccentric part (34a, 34b) gradually increases to 540 ° and 630 °, the volume of the first expansion chamber (52b) decreases, but the volume of the second expansion chamber (62a) becomes larger than that. Enlarged. The expansion of the total volume of the first expansion chamber (52b) and the second expansion chamber (62a) continues until just before the rotation angle of the eccentric portions (34a, 34b) reaches 720 °. As a result, in the expansion process, the refrigerant expands and is depressurized, and the power of the expanded refrigerant is converted into rotational power of the output shaft (34) via the piston (51, 61) and the eccentric part (34a, 34b). Is done. Thereby, the drive power of the compression mechanism (32) by an electric motor (33) is reduced, and energy saving of an air conditioning apparatus (10) is achieved. Further, also in the expansion process of the first operation, the auxiliary suction path (70) is closed by the valve body (83). Accordingly, no refrigerant is introduced from the auxiliary suction passage (70) into the first expansion chamber (52b) during the expansion process.

  In the next discharge process, the refrigerant flows out from the second fluid chamber (62) of the second expansion mechanism (42). Specifically, when the rotation angle of the eccentric portion (34a, 34b) is slightly rotated from the state of 720 °, the second expansion chamber (62a) and the outflow passage (48) communicate with each other, and the second expansion chamber (62a ) Becomes the low pressure chamber (62b). As the rotational angles of the eccentric portions (34a, 34b) gradually increase to 810 °, 900 °, and 990 °, the refrigerant in the low pressure chamber (62b) flows out to the outflow passage (48). The refrigerant outflow from the low pressure chamber (62b) to the outflow path (48) continues until the rotation angle of the eccentric parts (34a, 34b) reaches about 1080 °.

<Second operation>
In the second operation, the low pressure introduction valve (19) of the refrigerant circuit (11) is opened and the high pressure introduction valve (20) is closed. Thereby, as above-mentioned, the back side of the valve body (83) in a valve body chamber (80) becomes a low-pressure atmosphere. For this reason, the pressure on the back surface side of the valve body (83) is smaller than the pressure on the distal end side (first fluid chamber (52) side) of the valve body (83). Accordingly, the valve body (83) is displaced toward the radially outer side of the valve body chamber (80) against the biasing force of the spring member (87). As a result, the valve body (83) has the small diameter portion (85) with the tip end accommodated in the small diameter cylindrical portion (82) (see FIGS. 3 and 6). When the valve body (83) is displaced to the open position in this way, the third flow path (73) and the fourth flow path (74) of the auxiliary suction path (70) are connected, and the auxiliary suction path (70) and the first flow path are connected. The fluid chamber (52) communicates.

  In such a state, in the two-stage expansion unit (40), the suction process, the expansion process, and the discharge process are sequentially repeated in the same manner as in the first operation.

  In the inhalation process, the rotation angles of the eccentric parts (34a, 34b) are 0 ° (FIG. 6A), 90 ° (FIG. 6B), 180 ° (FIG. 6C) in the same manner as described above. As it gradually increases to 270 ° (FIG. 6D), the high-pressure refrigerant flows from the main suction passage (46) into the high-pressure chamber (52a). Here, when the rotation angle of the eccentric portions (34a, 34b) reaches about 220 °, the high pressure chamber (52a) and the outflow opening (75) of the auxiliary suction passage (70) begin to communicate with each other. Therefore, in the suction process of the second operation, the high-pressure refrigerant is introduced from both the main suction path (46) and the auxiliary suction path (70).

  In the next expansion process, after the rotation angle of the eccentric part (34a, 34b) reaches 360 °, the first expansion chamber (52b) communicates with the second expansion chamber (62a) via the communication path (47). To do. As the rotational angle of the eccentric portions (34a, 34b) gradually increases to 540 °, 630 °, and 720 °, the refrigerant expands in the expansion chambers (52b, 62a). Here, the first expansion chamber (52b) and the auxiliary suction passage (70) remain in communication until the rotation angle of the eccentric portions (34a, 34b) reaches about 580 °. Accordingly, in the expansion process of the second operation, the refrigerant is introduced from the auxiliary suction passage (70) into the first expansion chamber (52b).

  In the next discharge process, after the rotation angle of the eccentric part (34a, 34b) reaches 720 °, the second expansion chamber (62a) and the outflow path (48) communicate with each other. As the rotation angle of the eccentric portions (34a, 34b) gradually increases to 810 °, 900 °, 990 °, 1080 °, the refrigerant in the low pressure chamber (62b) flows out to the outflow passage (48). Here, the pressure of the refrigerant flowing out from the low pressure chamber (62b) during the second operation becomes higher than that during the first operation due to the introduction of the refrigerant from the auxiliary suction passage (70).

  As described above, in the two-stage expansion unit (40) of the present embodiment, the pressure of the refrigerant flowing out from the two-stage expansion unit (40) is appropriately changed by selectively switching between the first operation and the second operation. Can be adjusted. Accordingly, even when the suction pressure of the compression mechanism changes due to, for example, switching between the cooling operation and the heating operation, or a change in the outside air temperature, the two-stage expansion unit (40) causes the refrigerant to follow the refrigerant pressure. So that the occurrence of so-called overexpansion can be prevented.

-Effect of the embodiment-
In the above embodiment, the auxiliary suction passage (70) is formed in the first expansion mechanism (41) of the two-stage expansion unit (40), and the auxiliary suction passage (70) can be opened and closed by the valve body (83). Provided. Thereby, according to this embodiment, the amount of refrigerant sucked into the first fluid chamber (52) can be adjusted by opening and closing the valve body (83) and switching between the first operation and the second operation, and the compression is performed. The refrigerant circulation amount between the mechanism (32) and the two-stage expansion unit (40) can be balanced. As a result, even if the operating condition of the air conditioner (10) changes, it is possible to avoid the occurrence of overexpansion on the outflow side of the two-stage expansion unit (40), and power recovery in the two-stage expansion unit (40). Efficiency can be improved.

  Further, in the above embodiment, when the valve body (83) is in a state of closing the auxiliary suction passage (70) during the first operation, the tip of the valve body (83) is connected to the outflow opening of the auxiliary suction passage (70) ( 75) is almost completely occluded. Thereby, the space (dead volume) between the front-end | tip of a valve body (83) and a 1st fluid chamber (52) can be substantially eliminated. Thus, for example, when a dead volume is formed, the power recovery amount (work amount) is reduced due to the dead volume as shown by the solid line in FIG. As indicated by the broken line 13, the power recovery amount is not reduced, and the desired power recovery efficiency can be obtained by the two-stage expansion unit (40).

  Moreover, in the said embodiment, the pressure of the refrigerant | coolant which acts on the back surface of a valve body (83) is changed by switching the opening-and-closing state of a low pressure introduction valve (19) and a high pressure introduction valve (20), and a valve body (83 ) Can be easily switched. Further, since the spring member (87) for biasing the valve body (83) to the closed position is provided on the back side of the valve body (83), the valve body (83) in the first operation is in the first fluid chamber. Displacement back and forth due to the influence of the change in internal pressure in (52) can be avoided, and the generation of dead volume and the occurrence of vibrations can be reliably prevented.

  Furthermore, in the above embodiment, since the first flow path (71), the second flow path (72), and the third flow path (73) of the auxiliary suction path (70) are configured by the groove portions, the intermediate plate (44 ) And the first cylinder (50), it is easy to process these flow paths (71, 72, 73). Further, since the second flow path (72) has an arc shape extending in the circumferential direction of the first cylinder (50), in the first expansion mechanism (41), the auxiliary suction path (70) does not interfere with other members. ) Can be formed.

<< Modification of Embodiment >>
About the said embodiment, it is good also as a structure like each following modifications.

<Modification 1>
In the air conditioner (10) of Modification 1 shown in FIG. 7, in the air conditioner (10) of the above embodiment, the high pressure introduction valve (20) of the high pressure introduction pipe (28) is replaced with a capillary tube (90). Is. The capillary tube (90) constitutes a throttling portion that gives a predetermined resistance to the high-pressure refrigerant flowing through the high-pressure introduction pipe (28).

  In the first operation of the first modification, the low pressure introduction valve (19) is in a closed state. On the other hand, the high-pressure refrigerant on the high-pressure introduction pipe (28) side gradually passes through the capillary tube (90) and is sent to the back side of the valve element (83) through the main introduction pipe (26). As a result, the valve body (83) is displaced to the closed position by the high-pressure refrigerant and the spring member (87), and closes the outflow opening (75) of the auxiliary suction passage (70) (see FIGS. 4 and 5).

  On the other hand, in the second operation of the first modification, the low pressure introduction valve (19) is opened. As a result, the refrigerant on the back side of the valve body (83) gradually becomes a low-pressure atmosphere. Therefore, the valve body (83) is pressed to the open position by the internal pressure of the first fluid chamber (52), and the auxiliary suction passage (70 ) In the open state (see FIGS. 2 and 3). Here, since the capillary tube (90) is provided in the high pressure introduction pipe (28), the refrigerant on the high pressure introduction pipe (28) side is moved to the suction side of the first expansion mechanism (41) during the second operation. Leakage is minimized.

  As described above, in the first modification, the valve body (83) is provided without providing the open / close valves (19, 20) in both the low pressure introduction pipe (27) and the high pressure introduction pipe (28) as in the above embodiment. It can be displaced between the open and closed positions. Thereby, according to the modification 1, the structure of an air conditioning apparatus (10) and the opening / closing control of a valve body (83) can be simplified.

<Modification 2>
The air conditioner (10) of Modification 2 shown in FIG. 8 has a configuration in which the high pressure introduction pipe (28) and the high pressure introduction valve (20) are omitted from the air conditioner (10) of the above embodiment. . On the other hand, as shown in FIG. 9, the first expansion mechanism (41) of Modification 2 has a high-pressure distribution channel (77) formed in the first cylinder (50).

  The inflow end of the high pressure branch channel (77) communicates with the second channel (72) of the auxiliary suction channel (70), and the outflow end communicates with the valve body chamber (80). That is, the high-pressure distribution channel (77) is formed inside the first expansion mechanism (41) so that one end communicates with the auxiliary suction channel (70) and the other end communicates with the valve body chamber (80). This constitutes the high-pressure side introduction path. The high-pressure distribution channel (77) has a smaller channel cross section than the auxiliary suction channel (70). That is, the high-pressure branch channel (77) constitutes a throttle portion that provides resistance to the flow of the refrigerant flowing through the high-pressure branch channel (77).

  Further, the high-pressure distribution channel (77) is configured to switch the communication state with the valve body chamber (80) according to the opening / closing position of the valve body (83). Specifically, when the valve body (83) is in the open position, the outflow end of the high-pressure branch channel (77) is blocked by the large diameter portion (84) of the valve body (83). As a result, the high-pressure distribution channel (77) is partitioned from the back side of the valve body (83) through a slight gap (see FIG. 9A). On the other hand, when the valve body (83) is in the closed position, the outflow end of the high-pressure branch channel (77) is in communication with the back side of the valve body (83) (see FIG. 9B).

  In the first operation of the second modification, the low pressure introduction valve (19) is in a closed state. On the other hand, the high-pressure refrigerant on the auxiliary suction passage (70) side is sent to the periphery of the large-diameter portion (84) of the valve body (83) through the high-pressure branch passage (77). As a result, the refrigerant in the high-pressure distribution channel (77) gradually leaks from the periphery of the large diameter portion (84) to the back side of the valve element (83). For this reason, the pressure on the back side of the valve body (83) gradually increases, and the valve body (83) is displaced toward the closed position. As a result, the valve body (83) finally closes the outflow opening (75) of the auxiliary suction passage (70) (see FIG. 9B). In this state, the high-pressure distribution channel (77) is completely connected to the back side of the valve body (83), so that the valve body (83) is securely held in the closed position.

  On the other hand, in the second operation of the modified example 2, the low pressure introduction valve (19) is opened. As a result, the refrigerant on the back side of the valve body (83) gradually becomes a low-pressure atmosphere. Therefore, the valve body (83) is pressed to the open position by the internal pressure of the first fluid chamber (52), and the auxiliary suction passage (70 ) Is opened (see FIG. 9A). Here, since the outflow end of the high-pressure diversion channel (77) is substantially closed by the large-diameter portion (84) of the valve body (83), and the high-pressure diversion channel (77) constitutes a throttle portion, the auxiliary suction channel It is minimized that the (70) side refrigerant leaks to the back side of the valve body (83).

  As described above, in the second modification, the valve body (83) can be displaced between the open and closed positions without providing the high pressure introduction pipe (28) and the high pressure introduction valve (20) as in the above embodiment. . Thereby, according to the modification 2, the structure of an air conditioning apparatus (10) and the opening / closing control of a valve body (83) can be simplified.

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

  In each of the above embodiments, the auxiliary suction path (70), the main suction path (46), and the like may be formed at different locations. Specifically, in the example shown in FIGS. 10, 11, and 12, the main suction passage (46) is formed so as to penetrate the first cylinder (50) in the radial direction. On the other hand, in the auxiliary suction path (70) of the example of FIG. 10, the first flow path (71) is at the upper end surface of the first cylinder (50), and the second flow path (72) is below the intermediate plate (44). It is formed on the end face. Further, in the auxiliary suction path (70) of the example of FIG. 11, the first flow path (71) is at the lower end surface of the first cylinder (50) and the second flow path (72) is above the front head (43). It is formed on the end face.

  Furthermore, the auxiliary suction path (70) of the example shown in FIG. 12 has two branch flow paths (70a, 70b) and one merge flow path (74). Specifically, the two branch flow paths are an upper branch flow path (70a) formed on the upper end side of the first cylinder (50) and a lower branch formed on the lower end side of the first cylinder (50). And a flow path (70b). One end of each of the upper branch channel (70a) and the lower branch channel (70b) communicates with the main suction channel (46). On the other hand, the merged flow channel constitutes the fourth flow channel (74) of each of the above embodiments, and its start end communicates with the other ends of the upper branch flow channel (70a) and the lower branch flow channel (70b). ing. The terminal end of the fourth flow path (74) communicates with the suction / expansion process position of the first fluid chamber (52).

  In the example shown in FIG. 12, the sum of the channel cross sections of the auxiliary suction channel (70) is increased by forming two branch channels (70a, 70b) in the auxiliary suction channel (70). For this reason, in the state which opened the auxiliary suction path (70), the pressure loss in the auxiliary suction path (70) can be reduced. As a result, the pressure of the refrigerant introduced from the auxiliary suction path (70) into the first fluid chamber (52) can be suppressed from being reduced in the auxiliary suction path (70), and the power recovery efficiency can be increased. Even if the two branch channels (70a, 70b) are formed in this way, the valve element (83) opens and closes the outflow opening (75) of the merge channel (74). It is not necessary to provide a plurality of valve bodies (83) so as to correspond to the passages (70a, 70b).

  In the above embodiment, only one outflow opening (75) of the auxiliary suction passage (70) is provided in the fluid chamber (52), but two or more may be provided. In this case, a plurality of valve bodies (83) may be used so as to correspond to each outflow opening (75). In the above embodiment, the present invention is applied to the two-stage expansion unit having a plurality of expansion mechanisms. However, the present invention is applied to one expansion mechanism or an expansion unit including three or more expansion mechanisms. Alternatively, the auxiliary suction path (70) and the valve body (83) of the present invention may be applied to each of the expansion mechanisms.

  In the above embodiment, the present invention is applied to a so-called rotary-type volumetric expansion mechanism. However, the present invention may be applied to other expansion mechanisms such as a scroll-type expansion mechanism. Moreover, in the said embodiment, although this invention is applied about the air conditioning apparatus which air-conditions a room | chamber interior, this invention is applied to refrigeration apparatuses, such as a water heater, a chiller unit, a refrigerator which performs refrigeration / freezing in a warehouse, for example. May be applied.

  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 a refrigeration apparatus including an expansion mechanism that recovers the power of refrigerant expanded in a fluid chamber, and an expander applied to the refrigeration apparatus.

Drawing 1 is a schematic structure figure of a refrigerant circuit of an air harmony device concerning this embodiment. FIG. 2 is a longitudinal sectional view of the two-stage expansion unit, in which the valve body is in an open state. FIG. 3 is an enlarged sectional view showing a transverse section of the two-stage expansion unit, in which the valve body is opened. FIG. 4 is a longitudinal sectional view of the two-stage expansion unit, in which the valve body is in a closed state. FIG. 5 is an enlarged cross-sectional view showing a cross section of the two-stage expansion unit during the first operation, and illustrates the operation of the eccentric portion at every 90 ° rotation angle. FIG. 6 is an enlarged cross-sectional view showing a cross section of the two-stage expansion unit during the second operation, and illustrates the operation of the eccentric portion at every 90 ° rotation angle. FIG. 7 is a schematic configuration diagram of a refrigerant circuit of an air-conditioning apparatus according to Modification 1. FIG. 8 is a schematic configuration diagram of a refrigerant circuit of an air-conditioning apparatus according to Modification 2. FIG. 9 is an enlarged cross-sectional view showing a cross section of the two-stage expansion unit according to the modified example 2. FIG. 9 (A) shows the valve body in a closed state, and FIG. 9 (B) shows the valve body open. It is a state. FIG. 10 is a longitudinal sectional view of a two-stage expansion unit according to another modification 1, in which the valve body is in a closed state. FIG. 11 is a longitudinal sectional view of a two-stage expansion unit according to another modification 2 in which the valve body is in a closed state. FIG. 12 is a longitudinal sectional view of a two-stage expansion unit according to another modification 2 in which the valve body is in a closed state. FIG. 13 is a PV diagram showing the relationship between the cylinder volume and the refrigerant pressure in the expansion operation, for explaining the problem of the conventional example.

Explanation of symbols

10 Air conditioning equipment (refrigeration equipment)
19 Low pressure introduction valve (pressure control mechanism, opening control valve)
20 High-pressure introduction valve (pressure control mechanism, opening control valve)
26 Main introduction pipe (refrigerant introduction path)
27 Low pressure inlet pipe (refrigerant inlet, low pressure inlet)
28 High-pressure inlet pipe (refrigerant inlet, high-pressure inlet)
40 Two-stage expansion unit (expander)
41 First expansion mechanism (expansion mechanism)
43 Front head (blocking member)
44 Intermediate plate (blocking member)
50 First cylinder (first member)
51 First piston (second member)
52 First fluid chamber (fluid chamber)
70 Auxiliary suction path
70a Upper branch channel (Branch channel)
70b Lower branch channel (Branch channel)
71 First channel (auxiliary suction channel, groove)
72 Second channel (auxiliary suction channel, groove, arc channel)
73 Third channel (auxiliary suction channel, groove)
74 Fourth channel (auxiliary suction channel, merge channel)
75 Outflow opening (outflow end)
77 High-pressure distribution channel (refrigerant introduction path, high-pressure side introduction path, throttle part)
80 Valve chamber
83 Valve body (opening / closing member)
87 Spring member (biasing means)
90 Capillary tube (throttle part)

Claims (14)

A fluid chamber (52) is formed between the first member (50) and the second member (51) which are relatively eccentrically rotated, and the power of the refrigerant sucked into the fluid chamber (52) is recovered. A refrigeration apparatus comprising an expansion mechanism (41),
Inside the expansion mechanism (41) is formed an auxiliary suction path (70) branched from the suction side of the fluid chamber (52) and communicating with the suction / expansion process position of the fluid chamber (52),
An open / close member (83) for opening and closing the auxiliary suction path (70) is provided in the auxiliary suction path (70). In claim 1,
The opening / closing member is constituted by a valve body (83) that closes the outflow end (75) of the auxiliary suction passage (70) so as to follow the inner wall of the fluid chamber (52) in a closed state. Refrigeration equipment. In claim 1 or 2,
The refrigeration apparatus, wherein the auxiliary suction path (70) branches off from the suction side of the fluid chamber (52) and inside the expansion mechanism (41). In claims 1 to 3,
Inside the expansion mechanism (41) is formed a valve body chamber (80) for accommodating the valve body (83) so as to be displaceable between the open / close positions of the auxiliary suction passage (70),
A refrigerant introduction path (26, 27, 28, 77) that is connected to the valve body chamber (80) and introduces refrigerant to the back side of the valve body (83), and the refrigerant introduction path (26, 27, 28, 77) And a pressure control mechanism (19, 20) for controlling the pressure of the refrigerant. In claim 4,
The refrigerant introduction path has one end communicating with the outlet side of the expansion mechanism (41) and the other end connected to the valve body chamber (80), and one end of the expansion mechanism (41). A high-pressure side introduction path (28,77) communicating with the suction side and connected to the valve body chamber (80) at the other end;
The pressure control mechanism includes an opening degree adjusting valve (19, 20) for adjusting the opening degree of one or both of the low pressure side introduction path (27) and the high pressure side introduction path (28, 77). A refrigeration apparatus characterized by comprising: In claim 5,
The on-off control valve is composed of an on-off valve (19) for opening and closing the low-pressure side introduction path (27),
The refrigeration apparatus according to claim 1, wherein the high-pressure side introduction path (28, 77) is provided with a throttle portion (90) for imparting resistance to a refrigerant flow. In claim 5,
The high pressure side introduction path (77) is formed inside the expansion mechanism (41) so that one end communicates with the auxiliary suction path (70) and the other end communicates with the valve body chamber (80). A refrigeration apparatus characterized by. In any one of Claims 4 thru | or 7,
The refrigeration apparatus, wherein the valve body chamber (80) is provided with urging means (87) for urging the valve body (83) toward the closed position. In any one of claims 1 to 8,
The expansion mechanism includes a cylinder (50) as the first member, a piston (51) as the second member rotatably accommodated in the cylinder (50), and an end of the cylinder (50). A refrigeration apparatus comprising a rotary type expansion mechanism (41) having a closing member (43, 44) for closing the container. In claim 9,
The refrigeration apparatus, wherein the auxiliary suction path (70) includes an arc-shaped flow path (72) formed in the circumferential direction along the cylinder (50). In claim 9 or 10,
At least a part of the auxiliary suction passage (70) is constituted by a groove (71, 72, 73) formed on one or both end surfaces of the cylinder (50) and the closing member (43, 44). A refrigeration apparatus characterized by that. In any one of Claims 1 thru | or 11,
The auxiliary suction channel (70) includes a branch channel (70a, 70b) that branches into a plurality of channels from the suction side of the fluid chamber (52), and an outflow end of a plurality of branch channels (70a, 70b) at one end. And the other end has one merging channel (74) communicating with the suction / expansion process position of the fluid chamber (52),
The refrigeration apparatus, wherein the opening / closing member (83) is configured to open and close the merging channel (74). A fluid chamber (52) is formed between the first member (50) and the second member (51) which are relatively eccentrically rotated, and the power of the refrigerant sucked into the fluid chamber (52) is recovered. An expander provided with an expansion mechanism (41),
Inside the expansion mechanism (41) is formed an auxiliary suction path (70) branched from the suction side of the fluid chamber (52) and communicating with the suction / expansion process position of the fluid chamber (52),
An expander comprising an opening / closing member (83) for opening and closing the auxiliary suction passage (70) in the auxiliary suction passage (70). In claim 13,
The open / close member (83) includes a valve body (83) that closes the outflow end of the auxiliary suction passage (70) along the inner wall of the fluid chamber (52) in a closed state. Expanding machine.

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