JP2010156487A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain high COP regardless of changes in operating conditions, in a refrigerating device including a compressor constituted of a plurality of compression mechanisms mechanically connected by one drive shaft and performing a two-stage compression refrigerating cycle. <P>SOLUTION: An air conditioner (1) includes a refrigerant circuit (10) to which the compressor (11) having the three rotary type compression mechanisms (31, 32, 33) mechanically connected by one drive shaft (35) is connected so as to perform the two-stage compression refrigerating cycle. The rotary type compression mechanisms (31, 32, 33) are constituted of a one-cylinder chamber type compression mechanism and two-cylinder chamber type compression mechanisms. The air conditioner (1) further includes a suction volume ratio changing means (2) for changing a suction volume ratio which is a ratio of a suction volume between the low stage side compression mechanism and the high stage side compression mechanism of the compressor (11). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus for a two-stage compression refrigeration cycle, and more particularly to a technique for adjusting a volume ratio of a compressor in which a plurality of compression mechanisms are mechanically connected by a single drive shaft.

Conventionally, a refrigeration apparatus that performs a two-stage compression refrigeration cycle is known. In this refrigeration apparatus, for example, a compression mechanism in which two compression mechanisms are mechanically coupled to one drive shaft is used (see, for example, Patent Document 1). In the compressor of the refrigeration apparatus, one compression mechanism is a low-stage compression mechanism, and the other compression mechanism is a high-stage compression mechanism.
JP 2000-87892 A

  Here, for example, in a refrigeration cycle using carbon dioxide as a refrigerant, there is a problem that heat dissipation loss is large and it is difficult to obtain a high COP. Therefore, COP can be increased by performing multistage compression as described above. At this time, the intermediate pressure changes depending on the volume ratio of the low-stage compression mechanism and the high-stage compression mechanism. However, since the COP changes when the intermediate pressure changes, it is desirable to optimally control the intermediate pressure.

  When there are two compressors, a low-stage compressor and a high-stage compressor, the COP is changed by changing the refrigerant intake ratio (volume ratio) by changing the rotation speed of each compressor. Can be controlled. However, in a compressor in which two compression mechanisms are connected to one drive shaft as described in Patent Document 1, since the rotational speeds of the low-stage compression mechanism and the high-stage compression mechanism are equal, The ratio of the suction volume of the side compression mechanism and the high stage compression mechanism becomes constant, and the intermediate pressure cannot be controlled. This is not limited to the case where the refrigerant is carbon dioxide, and the same applies when another refrigerant is used.

  The present invention was devised in view of such problems, and an object of the present invention is to mechanically connect a plurality of compression mechanisms by a single drive shaft in a refrigeration apparatus that performs a two-stage compression refrigeration cycle. It is possible to adjust the volume ratio of the compressed compressor, and thus to enable the operation of the optimum COP.

  The first invention includes a refrigerant circuit (10) having a compressor (11) in which a plurality of rotary type compression mechanisms (31, 32, 33) are mechanically connected by a single drive shaft (35). It is premised on a refrigeration apparatus equipped with a two-stage compression refrigeration cycle.

  In this refrigeration apparatus, the compressor (11) includes three compression mechanism portions (31, 32, 33), and at least one compression mechanism portion is an annular ring that performs eccentric rotational motion in the cylinder space. The eccentric piston (62, 82) is composed of a two-cylinder chamber type compression mechanism (31, 33) having two cylinder chambers on the inner peripheral side and outer peripheral side, and the other compression mechanism unit is located in the cylinder space. It is composed of a one-cylinder chamber type compression mechanism having one cylinder chamber on the outer peripheral side of an eccentric piston (72) that performs eccentric rotational motion. In addition, there is provided suction volume ratio changing means (2) for changing the suction volume ratio, which is the ratio of the suction volume between the low stage side compression mechanism and the high stage side compression mechanism.

  In the first invention, the compressor (11) includes three compression mechanisms (31, 32, 33). Therefore, in the compressor (11), at least one of the three compression mechanism sections (31, 32, 33) is used as a low-stage compression mechanism, and at least one remaining is used as a high-stage compression mechanism. Thus, the refrigerant is compressed in two stages. The refrigeration apparatus further includes suction volume ratio changing means (2). Therefore, in this refrigeration apparatus, the suction volume ratio can be changed by the suction volume ratio changing means (2).

  According to a second invention, in the first invention, the two-cylinder chamber type compression mechanism section is configured as one compression mechanism section having two cylinder chambers, and two two-cylinder chamber type compression mechanism sections and one one cylinder are provided. A chamber-type compression mechanism is provided.

  According to a third aspect of the present invention, in the first aspect, the two-cylinder chamber type compression mechanism section is configured as two compression mechanism sections in which the two cylinder chambers are independent from each other. Two one-cylinder chamber type compression mechanisms are provided.

  In the second and third inventions, the suction volume ratio can be changed by the suction volume ratio changing means (2) even when the combination of the two-cylinder chamber type compression mechanism and the one-cylinder chamber type compression mechanism is changed. it can.

  In a fourth aspect based on any one of the first to third aspects, the suction volume ratio changing means (2) changes the connection relationship of the three compression mechanism portions (31, 32, 33). As a result, the suction volume ratio is changed.

  In the fourth invention, the three compression mechanism portions are provided, and the suction volume ratio can be changed by changing the connection relation of the three compression mechanism portions (31, 32, 33).

  In a fifth aspect based on the fourth aspect, the suction volume ratio changing means (2) includes two compression mechanisms used as a low-stage compression mechanism among the three compression mechanism portions (31, 32, 33). A switching mechanism (18, 19) for switching between a state in which the mechanism units (31, 32) are connected in series and a state in which the mechanism portions are connected in parallel is provided.

  In the fifth aspect of the invention, the two compression mechanism parts (31, 32) used as the low-stage compression mechanism are connected in series by the switching mechanism (18, 19) of the suction volume ratio changing means (2). The suction volume ratio is changed by switching between the states connected in parallel.

  Specifically, when the two compression mechanism portions (31, 32) are connected in parallel, the suction volume of the low-stage compression mechanism is the sum of the suction volumes of the two compression mechanism portions (31, 32). On the other hand, when the two compression mechanism portions (31, 32) are connected in series, the suction volume of the low-stage compression mechanism is the upstream compression mechanism portion (31 of the two compression mechanism portions (31, 32)). ) Intake volume. Therefore, when the two compression mechanisms (31, 32) are used as a low-stage compression mechanism and the connection relationship is changed from parallel to serial, the suction volume ratio increases, while the serial volume is changed from parallel to parallel. In this case, the suction volume ratio becomes small.

  According to a sixth aspect of the present invention based on the fourth aspect, the suction volume ratio changing means (2) includes two compression mechanisms used as a high-stage compression mechanism among the three compression mechanism portions (31, 32, 33). A switching mechanism (90, 91) is provided for switching between a state in which the mechanism units (32, 33) are connected in series and a state in which the mechanism portions are connected in parallel.

  In the sixth invention, the two compression mechanism parts (32, 33) used as the high-stage compression mechanism are connected in series by the switching mechanism (90, 91) of the suction volume ratio changing means (2). The suction volume ratio is changed by switching between the states connected in parallel.

  Specifically, when the two compression mechanism parts (32, 33) are connected in parallel, the suction volume of the high-stage compression mechanism is the sum of the suction volumes of the two compression mechanism parts (32, 33). On the other hand, when the two compression mechanism portions (32, 33) are connected in series, the suction volume of the high-stage compression mechanism is the upstream compression mechanism portion (32 of the two compression mechanism portions (32, 33)). ) Intake volume. Therefore, when the connection relationship of the two compression mechanisms (32, 33) is changed from parallel to serial, the suction volume ratio decreases, whereas when the connection relationship is changed from serial to parallel, the suction volume ratio increases. .

  In a seventh aspect based on the fourth aspect, any two compression mechanism portions (31, 32) of the three compression mechanism portions (31, 32, 33) are configured to have different suction volumes. The suction volume ratio changing means (2) has a switching mechanism (92, 93) for changing the connection relationship between the two compression mechanisms (31, 32) having different suction volumes.

  In the seventh aspect of the invention, the two compression mechanism portions (31, 32, 33) having different suction volumes among the three compression mechanism portions (31, 32, 33) are switched by the switching mechanism (92, 93) of the suction volume ratio changing means (2). , 32) is changed, the suction volume of at least one of the low-stage compression mechanism and the high-stage compression mechanism changes. Thereby, the suction volume ratio is changed.

  In an eighth aspect based on the seventh aspect, one of the two compression mechanisms (31, 32) is used as a low-stage compression mechanism and the other is used as a high-stage compression mechanism. ing.

  In the eighth invention, the switching mechanism (92, 93) of the suction volume ratio changing means (2) is used as a low-stage compression mechanism of the three compression mechanisms (31, 32, 33). If the connection relationship between (31) and the compression mechanism (32) used as the high-stage compression mechanism is changed, the compression mechanism (31) used as the low-stage compression mechanism before the change is On the other hand, the compression mechanism section (32) used as the high-stage compression mechanism is used as the low-stage compression mechanism. Accordingly, since the suction volume of at least one of the low stage side compression mechanism and the high stage side compression mechanism is changed, the suction volume ratio is changed.

  In a ninth aspect based on the first aspect, the suction volume ratio changing means (2) is configured such that the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33). The refrigerant is compressed in two of the three compression mechanism parts (31, 32, 33) in the above state, while the suction side and the discharge side are equal in the remaining one compression mechanism part. There is a switching mechanism (94, 95, 96, 97, 98) that switches to a second state in which the refrigerant enters a pressure state and passes without being compressed.

  In the ninth aspect of the invention, when the switching mechanism (94, 95, 96, 97, 98) of the suction volume ratio changing means (2) is switched from the first state to the second state, the three compression mechanism portions (31 , 32, 33), the suction side and the discharge side of any one of the compression mechanism portions are in the same pressure state, and the refrigerant is not compressed in the compression mechanism portion. Thereby, since the suction volume of the low stage side compression mechanism or the high stage side compression mechanism changes, the suction volume ratio is changed.

  In a tenth aspect based on the ninth aspect, the switching mechanism (94, 95, 96) is any one of the three compression mechanism portions (31, 32, 33) in the first state. While the two compression mechanism portions are connected in parallel, in the second state, the suction side and the discharge side of one compression mechanism portion of the two compression mechanism portions connected in parallel in the first state, Are configured to communicate with each other.

  In the tenth invention, when the first state is switched to the second state by the switching mechanism (94, 95, 96) of the suction volume ratio changing means (2), they are connected in parallel in the first state. In one compression mechanism part of the two compression mechanism parts, the suction side and the discharge side communicate with each other and are in an equal pressure state, so that the refrigerant passes through without being compressed. Thereby, since the suction volume of the low stage side compression mechanism or the high stage side compression mechanism changes, the suction volume ratio is changed.

  In an eleventh aspect based on the ninth aspect, any two compression mechanism sections (32, 33) of the three compression mechanism sections (31, 32, 33) are configured to have different suction volumes. In the first state, the switching mechanism (97, 98) is configured such that the two compression mechanism portions (32, 33) having different suction volumes are connected in series so that both the compression mechanism portions (32, 33) are low. While used as a stage-side compression mechanism or a high-stage side compression mechanism, in the second state, the upstream compression of the two compression mechanism parts (32, 33) connected in series in the first state. The suction side and the discharge side of the mechanism part (32) are configured to communicate with each other.

  In the eleventh invention, when the first state is switched to the second state by the switching mechanism (97, 98) of the suction volume ratio changing means (2), the first stage is connected in series and the low stage side Of the two compression mechanism parts (32, 33) used as the compression mechanism or the high-stage side compression mechanism, in the upstream compression mechanism part (32), the suction side and the discharge side communicate with each other and are at the same pressure state. Therefore, the refrigerant passes through without being compressed. Thereby, since the suction volume of the low stage side compression mechanism or the high stage side compression mechanism changes, the suction volume ratio is changed.

  In a twelfth aspect based on the first aspect, the three compression mechanism portions (31, 32, 33) include the first compression mechanism portion (31), the second compression mechanism portion (32), and the third The suction volume ratio changing means (2) is connected in series in the order of the compression mechanism section (33), and the suction volume ratio changing means (2) supplies the refrigerant between the first compression mechanism section (31) and the second compression mechanism section (32). The first compression mechanism (31) is cooled and used as the low-stage compression mechanism, while the second compression mechanism (32) and the third compression mechanism (33) are used as the high-stage compression mechanism. The first compression mechanism section (32) and the third compression mechanism section (33) are cooled to cool the refrigerant between the first compression mechanism section (32) and the third compression mechanism section (33). A switching mechanism (98) for switching to a second state in which the second compression mechanism (32) is used as a low-stage compression mechanism while the third compression mechanism (33) is used as a high-stage compression mechanism. Have.

  In the twelfth aspect, the suction volume ratio is changed by changing the position of the intermediate stage of the compressor (11) by the switching mechanism (98) of the suction volume ratio changing means (2).

  Specifically, in the first state, the suction volume of the low-stage compression mechanism is the suction volume of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism is the second compression mechanism section ( 32) suction volume. On the other hand, in the second state, the suction volume of the low-stage compression mechanism is the suction volume of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism is that of the third compression mechanism section (33). Inhalation volume. Therefore, by switching to the first state or the second state by the switching mechanism (98), the suction volume of the high-stage compression mechanism is changed, and the suction volume ratio is changed.

  In a thirteenth aspect based on any one of the first to twelfth aspects, the refrigerant flowing through the refrigerant circuit (10) is carbon dioxide.

  In the thirteenth invention, carbon dioxide as the refrigerant filled in the refrigerant circuit (10) is sucked into the low-stage compression mechanism and compressed to an intermediate pressure state, and then sucked into the high-stage compression mechanism. And compressed until a high pressure state higher than the critical pressure is reached.

  According to the present invention, since the suction volume ratio changing means (2) is provided, the intermediate pressure is changed (increased or lowered) so as to obtain a high COP by changing the suction volume ratio in accordance with the change of the operating condition. Can be reduced). Therefore, according to the present invention, a high COP can be obtained regardless of changes in operating conditions. In addition, since the two-cylinder chamber type compression mechanism (31, 33) has a characteristic that the torque fluctuation of the one-cylinder chamber type is small, all of the plurality of compression mechanism units are one-cylinder chamber type compression mechanism units. Vibration and noise can be suppressed compared to the constructed one.

  According to the second and third inventions, the suction volume ratio can be changed by the suction volume ratio changing means (2) even when the combination of the two cylinder chamber type compression mechanism and the one cylinder chamber side compression mechanism is changed. it can.

  According to the fourth aspect of the invention, since the three compression mechanism portions are provided, the connection relationship between the three compression mechanism portions (31, 32, 33) without changing the shape of the cylinder chamber of the compression mechanism portion. The suction volume ratio can be easily changed by changing.

  According to the fifth aspect of the invention, the switching mechanism (18, 19) of the suction volume ratio changing means (2) is used as a low-stage compression mechanism among the three compression mechanism portions (31, 32, 33). The suction volume ratio can be easily changed by switching the connection relationship between the two compression mechanism sections (31, 32) to be serial or parallel.

  Further, according to the sixth invention, the switching mechanism (90, 91) of the suction volume ratio changing means (2) is used as a higher stage compression mechanism among the three compression mechanism parts (31, 32, 33). The suction volume ratio can be easily changed by switching the connection relationship between the two compression mechanism sections (32, 33) to be serial or parallel.

  Further, according to the seventh and eighth inventions, the connection relationship between the two compression mechanism portions (31, 32) having different suction volumes is changed by the switching mechanism (92, 93) of the suction volume ratio changing means (2). By doing so, the suction volume ratio can be easily changed.

  Further, according to the ninth aspect, all the compression mechanisms (31, 32, 33) are compressed by the switching mechanism (94, 95, 96, 97, 98) of the suction volume ratio changing means (2). The refrigerant is compressed in the first state where the refrigerant is compressed in the mechanism part and in two of the three compression mechanism parts (31, 32, 33), while the remaining one compression mechanism part The suction volume ratio can be easily changed by switching between the second state in which the refrigerant passes without being compressed.

  According to the twelfth aspect, the suction volume ratio can be easily changed by changing the position of the intermediate stage of the compressor (11) by the suction volume ratio changing means (2).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, an air conditioner will be described as an example of the refrigeration apparatus according to the present invention.

Embodiment 1 of the Invention
-Overall configuration-
As shown in FIG. 1, the air conditioner (1) includes a refrigerant circuit (10) that performs a two-stage compression refrigeration cycle. The refrigerant circuit (10) includes a compressor (11), an outdoor heat exchanger (12), a first expansion valve (13), a gas-liquid separator (14), and a second expansion valve (15). And the indoor heat exchanger (16). The refrigerant circuit (10) includes a four-way valve (17) for switching between heating operation and cooling operation, and a first three-way valve (18) and a first three-way valve constituting a switching mechanism for suction volume ratio changing means (2) described later. Two three-way valves (19) are provided.

  Although the detailed configuration of the compressor (11) will be described later, the compressor (11) includes an airtight container-like casing (40). The casing (40) includes a first compression mechanism (31), a second compression mechanism (32), a third compression mechanism (33), and these three compression mechanisms (31, 32, 33). ) And a drive shaft (35) in which the three compression mechanisms (31, 32, 33) and the motor (34) are connected. Although details will be described later, in the compressor (11), at least one of the three compression mechanism parts (31, 32, 33) is used as a low-stage compression mechanism, while the remaining compression mechanism parts At least one of them is used as a high-stage compression mechanism and connected to the refrigerant circuit (10) so as to perform a two-stage compression refrigeration cycle.

  The casing (40) includes a first suction pipe (51), a first discharge pipe (52), a second suction pipe (53), a second discharge pipe (54), so as to penetrate the casing (40). A third suction pipe (55) and a high-pressure discharge pipe (56) are provided.

  The first suction pipe (51) is connected to the suction side of the first compression mechanism section (31), and the first discharge pipe (52) is connected to the discharge side of the first compression mechanism section (31). Yes. The second suction pipe (53) is connected to the suction side of the second compression mechanism section (32), and the second discharge pipe (54) is connected to the discharge side of the second compression mechanism section (32). Has been. Further, the third suction pipe (55) is connected to the suction side of the third compression mechanism (33), while the discharge side of the third compression mechanism (33) is the internal space (S1 of the casing (40)). ) Is open. The high-pressure discharge pipe (56) is provided in the upper part of the casing (40), and the inner end thereof opens in the internal space (S1) of the casing (40).

  The four-way valve (17) includes first to fourth ports (P1, P2, P3, P4), communicates the first port (P1) and the second port (P2) and the third port (P3). The first position (solid line in FIG. 1) that communicates with the fourth port (P4), the first port (P1) and the fourth port (P4), and the second port (P2) and the third port It is configured to be switchable to a second position (broken line in FIG. 1) for communicating with the port (P3). The four-way valve (17) is switched between a first position and a second position by a controller (not shown).

  The first port (P1) of the four-way valve (17) is connected to the other end of the high-pressure gas pipe (21) having one end connected to the high-pressure discharge pipe (56). One end of the first gas pipe (22) is connected to the second port (P2) of the four-way valve (17). The other end of the first gas pipe (22) is connected to the gas side end of the outdoor heat exchanger (12).

  The outdoor heat exchanger (12) is a cross fin type fin-and-tube heat exchanger. One end of the first liquid pipe (23a) is connected to the liquid side end of the outdoor heat exchanger (12), and the gas-liquid separator (14) is connected to the other end of the first liquid pipe (23a). Has been. The first liquid pipe (23a) is provided with a first expansion valve (13).

  One end of a second liquid pipe (23b) is connected to the gas-liquid separator (14). The other end of the second liquid pipe (23b) is connected to the liquid side end of the indoor heat exchanger (16). The second liquid pipe (23b) is provided with a second expansion valve (15).

  The indoor heat exchanger (16) is a cross-fin type fin-and-tube heat exchanger. One end of the second gas pipe (24) is connected to the gas side end of the indoor heat exchanger (16), and the other end of the second gas pipe (24) is the fourth port of the four-way valve (17). (P4) connected.

  One end of a low-pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17). The other end of the low pressure gas pipe (25) is connected to the first suction pipe (51). One end of the low-pressure gas branch pipe (25a) is connected to the middle part of the low-pressure gas pipe (25), and the other end of the low-pressure gas branch pipe (25a) is the first port of the second three-way valve (19). Connected to (P1).

  One end of a first communication pipe (26) is connected to the first discharge pipe (52), and the other end of the first communication pipe (26) is connected to a second port ( Connected to P2). One end of the second connecting pipe (27) is connected to the third port (P3) of the first three-way valve (18), and the other end of the second connecting pipe (27) is connected to the second three-way valve. It is connected to the third port (P3) of (19). In addition, one end of a third connecting pipe (28) is connected to the second port (P2) of the second three-way valve (19), and the other end of the third connecting pipe (28) is connected to the second suction pipe ( 53) is connected.

  One end of a fourth connecting pipe (29) is connected to the second discharge pipe (54), and the other end of the fourth connecting pipe (29) is connected to the third suction pipe (55). . One end of a fourth connecting / merging pipe (29a) is connected to the middle part of the fourth connecting pipe (29), and the other end of the fourth connecting / merging pipe (29a) is connected to the first three-way valve (18). Connected to the first port (P1). One end is connected to the gas-liquid separator (14) on the third suction pipe (55) side of the connection part of the fourth communication junction pipe (29a) in the middle of the fourth communication pipe (29). The other end of the injection pipe (20) is connected. The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  The first three-way valve (18) and the second three-way valve (19) include first to third ports (P1, P2, P3), respectively, and the first port (P1) and the second port (P2). And a second position where the second port (P2) and the third port (P3) communicate with each other. The first three-way valve (18) and the second three-way valve (19) are switched between a first position and a second position by a controller (not shown).

  The air conditioner (1) also changes the ratio of the suction volume between the low-stage compression mechanism and the high-stage compression mechanism (hereinafter simply referred to as “suction volume ratio”) of the compressor (11). A suction volume ratio changing means (2) is provided. In the first embodiment, the suction volume ratio changing means (2) changes the connection ratio of the three compression mechanism portions (31, 32, 33) of the compressor (11) to change the suction volume ratio. Is configured to change.

  Specifically, the suction volume ratio changing means (2) includes a first compression mechanism part (31) and a second compression mechanism part (32) used as a low-stage compression mechanism, connected in series. A switching mechanism for switching between the state and the second state connected in parallel is provided. In the first embodiment, the switching mechanism is configured by the first three-way valve (18) and the second three-way valve (19), and is in the first state as the operating condition of the air conditioner (1) changes. And the second state.

−Compressor configuration−
As shown in FIG. 2, the compressor (11) of the present embodiment is a so-called hermetic compressor, and as described above, the first compression mechanism section (31) and the second compression mechanism section (32). A third compression mechanism section (33), an electric motor (34) for driving the three compression mechanism sections (31, 32, 33), three compression mechanism sections (31, 32, 33), and an electric motor A drive shaft (35) that couples (34) is accommodated in one casing (40).

  The casing (40) is formed in a vertically long cylindrical closed container shape. Specifically, the casing (40) includes a main body cylinder portion (41), an upper end plate (42), and a lower end plate (43). The main body cylinder portion (41) is formed in a hollow cylindrical shape whose both ends are open ends. In the casing (40), the upper end of the main body tube portion (41) is closed by the upper end plate (42), and the lower end of the main body tube portion (41) is closed by the lower end plate (43).

  In the casing (40), the electric motor (34) is disposed above the three compression mechanisms (31, 32, 33). The drive shaft (35) that connects the three compression mechanism sections (31, 32, 33) and the electric motor (34) is disposed in a posture in which the axial direction is the vertical direction.

  The electric motor (34) includes a rotor (34a) and a stator (34b). The rotor (34a) is fixed to the upper end of the drive shaft (35), while the stator (34b) is fixed to the main body cylinder (41) of the casing (40).

  The drive shaft (35) includes a main shaft portion (35a), a first eccentric portion (35b), a second eccentric portion (35c), and a third eccentric portion (35d). The three eccentric portions (35b, 35c, 35d) are formed in portions of the drive shaft (35) that pass through the respective compression mechanism portions (31, 32, 33). In the drive shaft (35), the second eccentric portion (35c) is disposed above the first eccentric portion (35b), and the third eccentric portion (35d) is disposed above the second eccentric portion (35c). . The three eccentric parts (35b, 35c, 35d) are all formed in a cylindrical shape whose outer diameter is larger than that of the main shaft part (35a), and the outer diameters of the two eccentric parts (35b, 35d) on the upper and lower sides are equal. The outer diameter of the central one eccentric portion (35c) is larger than that. Further, the shaft centers of the eccentric portions (35b, 35c, 35d) are eccentric with respect to the shaft center of the main shaft portion (35a). The eccentric direction of the first eccentric portion (35b) with respect to the main shaft portion (35a) and the eccentric direction of the third eccentric portion (35d) with respect to the main shaft portion (35a) are shifted by 180 ° in the rotational direction of the drive shaft (35). Yes.

  The three compression mechanisms (31, 32, 33) are integrally formed, and from the bottom to the top, the rear head (36), the first cylinder (61), the first middle plate (38), and the second cylinder ( 71), the second middle plate (39), the third cylinder (81) and the front head (37) are laminated in order.

  Next, a specific configuration of the compression mechanism section (31, 32, 33) will be described. First, the 1st compression mechanism part (31) and the 3rd compression mechanism part (33) which are 2 cylinder chamber type compression mechanism parts are demonstrated.

  As shown in FIGS. 2 and 3, the first compression mechanism (31) includes a first cylinder (61) that forms an annular first cylinder chamber (C11, C12), and the first cylinder chamber (C11). , C12) and a first piston (62) having an annular piston member (62b) dividing the first cylinder chamber (C11, C12) into an outer compression chamber (C11) and an inner compression chamber (C12) And a first blade (63) that partitions the first cylinder chamber (C11, C12) into a high pressure chamber and a low pressure chamber. The first cylinder (61) and the first piston (62) are configured to relatively eccentrically rotate. In the first embodiment, the first cylinder (61) constitutes a fixed member of the first compression mechanism (31), and the first piston (62) serves as a movable member of the first compression mechanism (31). It is composed.

  The first cylinder (61) includes a plate-shaped end plate portion (61a) having a bearing portion formed in the center, and a cylindrical outer cylinder member formed so as to protrude upward from the end plate portion (61a). 61b) and an inner cylinder member (61c). The first cylinder (61) is fixed by welding the end plate part (61a) and the outer cylinder member (61b) to the inner surface of the main body cylinder part (41) of the casing (40). The main shaft portion (35a) of the drive shaft (35) is inserted into the bearing portion of the end plate portion (61a), and the main shaft portion (35a) of the drive shaft (35) is the bearing portion of the end plate portion (61a). It is rotatably supported by a sliding bearing.

  A first suction port (51a) extending radially inward from the outer peripheral surface is formed in the end plate portion (61a) of the first cylinder (61). One end of the first suction port (51a) is configured to communicate with the outer compression chamber (C11) and the inner compression chamber (C12), and the first suction pipe (51) is connected to the other end. . That is, the first suction port (51a) constitutes a first suction passage through which the refrigerant sucked from the first suction pipe (51) to the outer compression chamber (C11) and the inner compression chamber (C12) flows.

  Further, a first discharge port (52a) extending radially inward from the outer peripheral surface is formed in the end plate portion (61a) of the first cylinder (61). One end of the first discharge port (52a) is configured to communicate with the outer compression chamber (C11) and the inner compression chamber (C12), and the first discharge pipe (52) is connected to the other end. . Specifically, the discharge ports (66, 67) of the outer compression chamber (C11) and the inner compression chamber (C12) are opened in the first discharge port (52a), and both the discharge ports (66, 67) are opened. Is provided with a discharge valve (68, 69). The discharge valve (68) of the outer compression chamber (C11) opens the discharge port (66) when the differential pressure between the high pressure chamber of the outer compression chamber (C11) and the first discharge port (52a) reaches a set value. It is configured. Similarly, when the differential pressure between the high pressure chamber of the inner compression chamber (C12) and the first discharge port (52a) reaches a set value, the discharge valve (69) of the inner compression chamber (C12) Is configured to open.

  The inner peripheral surface of the outer cylinder member (61b) and the outer peripheral surface of the inner cylinder member (61c) are formed as cylindrical surfaces arranged on the same center. An outer compression chamber (C11) is formed between the outer peripheral surface of the annular piston member (62b) of the first piston (62) and the inner peripheral surface of the outer cylinder member (61b), and the first piston (62) An inner compression chamber (C12) is formed between the inner peripheral surface of the annular piston member (62b) and the outer peripheral surface of the inner cylinder member (61c).

  The first piston (62) includes a flat end plate portion (62a), an annular piston member (62b) formed on one side of the end plate portion (62a), and an inner side of the annular piston member (62b). And a cylindrical bearing portion (62c) formed. The annular piston member (62b) is formed in a C shape in which a part of the annular ring is divided. The first eccentric portion (35b) of the drive shaft (35) is slidably fitted into the bearing portion (62c). A space (80) is formed between the bearing portion (62c) and the inner cylinder member (61c), but the refrigerant is not compressed in the space (80).

  The first blade (63) extends from the inner peripheral surface of the outer cylinder member (61b) to the outer peripheral surface of the inner cylinder member (61c) in the radial direction of the first cylinder chamber (C11, C12). And the 1st braid | blade (63) is comprised so that the 1st cylinder chamber (C11, C12) may be divided into a high pressure chamber and a low pressure chamber by inserting the parting part of an annular piston member (62b). The first blade (63) may be formed integrally with the outer cylinder member (61b) and the inner cylinder member (61c), or may be formed separately from both the cylinder members (31b, 31c) and fixed thereto. May be.

  Further, the first compression mechanism (31) is provided at a parting position of the annular piston member (62b), and a first swing that connects the first piston (62) and the first blade (63) so as to be swingable. It has a bush (65). The first rocking bush (65) is a pair of members having the same shape, and both of them have a substantially semicircular cross-sectional shape. The first blade (63) is sandwiched between the opposing surfaces of the first swing bush (65) so as to be able to advance and retract. The first swing bush (65) is swingable with respect to the first piston (62) in a state where the first blade (63) is sandwiched. Note that the first swing bush (65) may be integrally formed by being partially connected.

  In the first compression mechanism section (31), the first piston (62) performs an eccentric rotational motion with respect to the first cylinder (61). In the eccentric rotational movement, the outer peripheral surface of the annular piston member (62b) and the inner peripheral surface of the outer cylinder member (61b) are slidably contacted at one point through the oil film, and the phase of the slidable contact is shifted by 180 °. In this position, the inner peripheral surface of the annular piston member (62b) and the outer peripheral surface of the inner cylinder member (61c) are configured to slidably contact at one point through an oil film.

  The third compression mechanism section (33) is constituted by the same mechanical elements as the first compression mechanism section (31). The third compression mechanism (33) is provided in a state where the first compression mechanism (31) is reversed with the second cylinder (71) interposed therebetween. In addition, in FIG. 3, the code | symbol regarding the component of a 3rd compression mechanism part (33) is shown in the parenthesis.

  Specifically, the third compression mechanism (33) includes a third cylinder (81) that forms an annular third cylinder chamber (C31, C32), and the third cylinder chamber (C31, C32). A third piston (82) having an annular piston member (82b) which is positioned to partition the third cylinder chamber (C31, C32) into an outer compression chamber (C31) and an inner compression chamber (C32); A third blade (83) that divides the chamber (C31, C32) into a high-pressure chamber and a low-pressure chamber is provided.

  The third cylinder (81) and the third piston (82) are configured to relatively eccentrically rotate. In the first embodiment, the third cylinder (81) constitutes a fixed member of the third compression mechanism (33), and the third piston (82) acts as a movable member of the third compression mechanism (33). It is composed.

  The third cylinder (81) includes a flat end plate portion (81a) having a bearing portion formed in the center, and a cylindrical outer cylinder member (81b) formed to protrude downward from the end plate portion (81a). And an inner cylinder member (81c). The third cylinder (81) is fixed by welding the end plate portion (81a) and the outer cylinder member (81b) to the inner surface of the main body cylinder portion (41) of the casing (40). Further, the main shaft portion (35a) of the drive shaft (35) is inserted into the bearing portion of the end plate portion (81a), and the main shaft portion (35a) of the drive shaft (35) is the bearing portion of the end plate portion (81a). It is rotatably supported by a sliding bearing.

  A second suction port (55a) extending radially inward from the outer peripheral surface is formed on the end plate portion (81a) of the third cylinder (81). One end of the second suction port (55a) is configured to communicate with the outer compression chamber (C31) and the inner compression chamber (C32), and the third suction pipe (55) is connected to the other end. . That is, the second suction port (55a) constitutes a third suction passage through which the refrigerant sucked from the third suction pipe (55) to the outer compression chamber (C31) and the inner compression chamber (C32) flows.

  Further, a third discharge port (56a) extending downward from the upper surface is formed in the end plate portion (81a) of the third cylinder (81). One end of the 32 discharge port (56a) is configured to communicate with the outer compression chamber (C31) and the inner compression chamber (C32), and the other end opens into the internal space (S1) of the casing (40). . Specifically, the discharge port (86, 87) of the outer compression chamber (C31) and the inner compression chamber (C32) is opened in the third discharge port (56a), and both the discharge ports (86, 87) are opened. Are provided with discharge valves (88, 89). The discharge valve (88) of the outer compression chamber (C31) opens the discharge port (86) when the differential pressure between the high pressure chamber of the outer compression chamber (C31) and the third discharge port (56a) reaches a set value. It is configured. Similarly, the discharge valve (89) of the inner compression chamber (C32) causes the discharge port (87) when the differential pressure between the high pressure chamber of the inner compression chamber (C32) and the third discharge port (56a) reaches a set value. Is configured to open.

  The inner peripheral surface of the outer cylinder member (81b) and the outer peripheral surface of the inner cylinder member (81c) are formed on cylindrical surfaces disposed on the same center. An outer compression chamber (C31) is formed between the outer peripheral surface of the annular piston member (82b) of the third piston (82) and the inner peripheral surface of the outer cylinder member (81b), and the third piston (82) An inner compression chamber (C32) is formed between the inner peripheral surface of the annular piston member (82b) and the outer peripheral surface of the inner cylinder member (81c).

  The third piston (82) includes a plate-shaped end plate portion (82a), an annular piston member (82b) formed on one side of the end plate portion (82a), and an annular piston member of the end plate portion (82a). (82b) and a cylindrical bearing portion (82c) formed inside. The annular piston member (82b) is formed in a C shape in which a part of the annular ring is divided. The upper eccentric portion (35d) of the drive shaft (35) is slidably fitted into the bearing portion (82c). A space (85) is formed between the bearing portion (82c) and the inner cylinder member (81c), but refrigerant is not compressed in this space (85).

  The third blade (83) extends from the inner peripheral surface of the outer cylinder member (81b) to the outer peripheral surface of the inner cylinder member (81c) in the radial direction of the third cylinder chamber (C31, C32). And the 3rd braid | blade (83) is comprised so that the 3rd cylinder chamber (C31, C32) may be divided into a high pressure chamber and a low pressure chamber by inserting the parting part of an annular piston member (82b). In the present embodiment, the third blade (83) is integrally formed with the outer cylinder member (81b) and the inner cylinder member (81c), but is formed as a separate member from both the cylinder members (41b, 41c). And you may fix to these.

  The third compression mechanism (33) is provided at a parting position of the annular piston member (82b), and connects the third piston (82) and the third blade (83) in a swingable manner. It has a bush (85). The third oscillating bush (85) is a pair of members having the same shape, both of which have a substantially semicircular cross section. The third blade (83) is sandwiched between the opposed surfaces of the third rocking bush (85) so as to freely advance and retract. The third swing bush (85) is swingable with respect to the third piston (82) in a state where the third blade (83) is sandwiched. In addition, you may form both bushes (44a, 44b) integrally by connecting in part.

  In the third compression mechanism section (33), the third piston (82) performs an eccentric rotational motion with respect to the third cylinder (81). In the eccentric rotational movement, the outer peripheral surface of the annular piston member (82b) and the inner peripheral surface of the outer cylinder member (81b) are slidably contacted at substantially one point via an oil film, and the phase of the slidable contact is shifted by 180 °. In this position, the inner peripheral surface of the annular piston member (82b) and the outer peripheral surface of the inner cylinder member (81c) are configured to be in sliding contact with each other substantially at one point.

  The first middle plate (38) includes a cylindrical portion (38a) that covers the outer peripheral side of the end plate portion (62a) of the first piston (62) disposed so as to face each other, and an interior of the cylindrical portion (38a). The first plate (62) includes a disk-shaped flat plate portion (38b) extending in parallel with the end plate portion (62a) of the first piston (62). The cylinder portion (38a) is provided so as to contact the outer cylinder member (61b) of the first cylinder (61).

  The second middle plate (39) includes a cylindrical portion (39a) that covers the outer peripheral side of the end plate portion (82a) of the third piston (82) disposed so as to face each other, and an interior of the cylindrical portion (39a). In FIG. 3, the end plate portion (82a) of the third piston (82) and the disk-shaped flat plate portion (39b) extending in parallel with the end plate portion (82a). The cylinder portion (39a) is provided so as to contact the outer cylinder member (81b) of the third cylinder (81).

  Next, the 2nd compression mechanism part which is a 1 cylinder chamber type compression mechanism part is demonstrated.

  As shown in FIGS. 2 and 5, the second cylinder (71) is a thick cylindrical member, and both end faces (upper end face and lower end face in FIG. 2) are mutually perpendicular to the axis perpendicular to the axis. It is a parallel flat surface. A drive shaft (35) is inserted into the second cylinder (71). The second eccentric portion (35c) of the drive shaft (35) is located inside the second cylinder (71).

  The first middle plate (38) and the second middle plate (39) are constituted by flat plate members that are slightly thinner than the second cylinder (71). The second cylinder (71) is located between the first middle plate (38) and the second middle plate (39), the lower surface is in close contact with the first middle plate (38), and the upper surface is the second middle plate. It is in close contact with (39). A through hole penetrating in the thickness direction is formed in the first middle plate (38) and the second middle plate (39), and a drive shaft (35) is inserted through the through hole.

  A second piston (72) is accommodated in the second cylinder (71), and a second cylinder chamber (C2) is provided between the inner peripheral surface of the second cylinder (71) and the outer peripheral surface of the second piston (72). Is formed. The upper end of the second cylinder chamber (C2) is closed by the lower surface of the second middle plate (39), and the lower end of the second cylinder chamber (C2) is closed by the upper surface of the first middle plate (38). The outer peripheral surface of the second piston (72) is in sliding contact with the inner peripheral surface of the second cylinder (71) through an oil film at one place in the circumferential direction. The second piston (72) engaged with the second eccentric portion (35c) rotates eccentrically with its outer peripheral surface in contact with the inner peripheral surface of the second cylinder (71).

  FIG. 5 is a cross-sectional view of the second compression mechanism section (32). As shown in FIG. 5, a blade (73) is formed integrally with the second piston (72). The blade (73) is formed in a flat plate shape extending outward from the outer peripheral surface of the piston (72). The cylinder chamber (C2) is partitioned by the blade (73) into a low pressure chamber that is a first chamber and a high pressure chamber that is a second chamber.

  The second cylinder (71) is formed with a blade groove (74) for inserting the blade (73). A second swing bush (75) for supporting the blade (73) is inserted into the blade groove (74) of the cylinder (71).

  Two second swing bushes (75) are provided in the cylinder (71), and the blade (73) is sandwiched between the second swing bushes (75). Each of the second swing bushes (75) has a flat front surface in sliding contact with the side surface of the blade (73), and a back surface in circular arc surface in sliding contact with the cylinder (71). The second swing bush (75) is rotatable with respect to the cylinder (71), and the blade (73) is movable back and forth with respect to the second swing bush (75). The pair of second swing bushes (75) provided in each cylinder (71) may be partially connected to form an integral structure.

  With this configuration, when the drive shaft (35) is driven and the piston (72) rotates eccentrically with respect to the axis of the drive shaft (35), the blade (73) formed integrally with the piston (72) Swings around the center point of the second swing bush (75) while moving back and forth along the second swing bush (75).

  A suction port (76) is formed in the second cylinder (71). The suction port (76) is formed so as to extend in the radial direction and communicate with the inside and outside of the cylinder (71). The second suction pipe (53) is connected to the suction port (76) formed in the second cylinder (71).

  Although not shown, the second cylinder (71) is formed with a discharge space and a discharge port that communicates the discharge space with the second cylinder chamber (C2). The discharge port is formed so as to penetrate the inside and the outside of the second cylinder (71), and a discharge valve is attached to the outer end portion thereof. The second discharge pipe (54) is connected to the discharge space.

  As described above, the present invention provides a refrigerant circuit (11) having a compressor (11) in which a plurality of rotary type compression mechanisms (31, 32, 33) are mechanically connected by a single drive shaft (35). 10), a refrigeration apparatus that performs a two-stage compression refrigeration cycle, and the compressor (11) includes three compression mechanism portions (31, 32, 33). Then, at least one (two in this example) compression mechanism section includes two cylinder chambers on the inner peripheral side and the outer peripheral side of the annular eccentric piston (62, 82) that performs eccentric rotational movement in the cylinder space. It is composed of a two-cylinder chamber type compression mechanism (31, 33) having the other (one) compression mechanism on the outer peripheral side of the eccentric piston (72) that performs eccentric rotational movement in the cylinder space. It is comprised by the type | mold compression mechanism part (32) of one cylinder chamber which has one cylinder chamber. In addition, there is provided suction volume ratio changing means (2) for changing the suction volume ratio, which is the ratio of the suction volume between the low stage side compression mechanism and the high stage side compression mechanism.

  In this embodiment, the two-cylinder chamber type compression mechanism is configured as one compression mechanism unit in which the two cylinder chambers function integrally, and two two-cylinder chamber type compression mechanism units and one one-cylinder chamber type compression are formed. A mechanism is provided.

-Driving action-
(Operation of compression mechanism)
Next, the operation of the compressor (11) will be described. First, the first compression mechanism section (31) will be described. The refrigerant is compressed in the first compression mechanism section (31).

  First, when the electric motor (20) is started, the annular piston member (62b) of the first piston (62) reciprocates (advances and retracts) along the first blade (63) and swings. At that time, the first swing bush (65) substantially makes surface contact with the annular piston member (62b) and the first blade (63). Then, the annular piston member (62b) revolves while swinging with respect to the outer cylinder member (61b) and the inner cylinder member (61c), and the first compression mechanism portion (31) performs a compression operation.

  Specifically, in the outer compression chamber (C11), the volume of the low-pressure chamber is substantially minimized in the state of FIG. 4B, and from here the drive shaft (35) rotates in the direction of the arrow in FIG. C) to 4A, the volume of the low pressure chamber increases, and the refrigerant in the first suction port (51a) is sucked into the low pressure chamber of the outer compression chamber (C11).

  Then, when the drive shaft (35) makes one revolution and enters the state of FIG. 4 (B) again, the suction of the refrigerant into the low pressure chamber is completed. The low-pressure chamber becomes a high-pressure chamber in which the refrigerant is compressed, and a new low-pressure chamber is formed across the first blade (63). When the drive shaft (35) further rotates, the suction of the refrigerant is repeated in the low pressure chamber, while the volume of the high pressure chamber is reduced, and the refrigerant is compressed in the high pressure chamber. When the high pressure chamber reaches a predetermined pressure and the differential pressure from the first discharge port (52a) reaches a set value, the discharge valve opens, and the intermediate pressure refrigerant in the high pressure chamber passes through the first discharge port (52a). It flows out to the discharge pipe (52).

  In the inner compression chamber (C12), the volume of the low pressure chamber is substantially minimized in the state of FIG. 4 (F), and from here the drive shaft (35) rotates in the direction of the arrow in FIG. The volume of the low pressure chamber increases with the change to the state of 4 (E), and the refrigerant in the first suction port (51a) is sucked into the low pressure chamber of the inner compression chamber (C12).

  Then, when the drive shaft (35) makes one revolution and again enters the state of FIG. 4 (F), the suction of the refrigerant into the low pressure chamber is completed. The low-pressure chamber becomes a high-pressure chamber in which the refrigerant is compressed, and a new low-pressure chamber is formed across the first blade (63). When the drive shaft (35) further rotates, the suction of the refrigerant is repeated in the low pressure chamber, while the volume of the high pressure chamber is reduced, and the refrigerant is compressed in the high pressure chamber. When the high pressure chamber reaches a predetermined pressure and the differential pressure from the first discharge port (52a) reaches a set value, the discharge valve opens, and the refrigerant in the high pressure chamber passes through the first discharge port (52a) through the first discharge pipe ( 52).

  In the outer compression chamber (C11), the refrigerant starts to be discharged almost at the timing shown in FIG. 4E, and in the inner compression chamber (C12), the discharge starts almost at the timing shown in FIG. 4A. That is, the discharge timing is shifted by approximately 180 ° between the outer compression chamber (C11) and the inner compression chamber (C12). For this reason, torque fluctuation is reduced.

  In the third compression mechanism section (33), the refrigerant is compressed in substantially the same manner as in the first compression mechanism section (31).

  When the electric motor (20) is started, the annular piston member (82b) of the third piston (82) reciprocates (advances and retracts) along the third blade (83) and swings. At that time, the third rocking bush (85) substantially makes surface contact with the annular piston member (82b) and the third blade (83). Then, the annular piston member (82b) revolves while swinging with respect to the outer cylinder member (81b) and the inner cylinder member (81c), and the third compression mechanism portion (33) performs a compression operation.

  Specifically, in the outer compression chamber (C31), the volume of the low-pressure chamber is substantially minimized in the state of FIG. 4B, and from here the drive shaft (35) rotates in the direction of the arrow in FIG. C) to the state shown in FIG. 4A, the volume of the low pressure chamber increases, and the refrigerant in the second suction port (55a) is sucked into the low pressure chamber of the outer compression chamber (C31).

  Then, when the drive shaft (35) makes one revolution and enters the state of FIG. 4 (B) again, the suction of the refrigerant into the low pressure chamber is completed. The low-pressure chamber becomes a high-pressure chamber in which the refrigerant is compressed, and a new low-pressure chamber is formed across the third blade (83). When the drive shaft (35) further rotates, the suction of the refrigerant is repeated in the low pressure chamber, while the volume of the high pressure chamber is reduced, and the refrigerant is compressed in the high pressure chamber. When the high pressure chamber reaches a predetermined pressure and the differential pressure from the third discharge port (56a) reaches a set value, the discharge valves (88, 89) are opened, and the high pressure refrigerant in the high pressure chamber is discharged to the third discharge port (56a). To the internal space (S1) in the casing (40).

  In the inner compression chamber (C32), the volume of the low-pressure chamber is substantially minimized in the state of FIG. 4 (F), and from here the drive shaft (35) rotates in the direction of the arrow in FIG. 4 (G) to FIG. The volume of the low pressure chamber increases with the change to the state of 4 (E), and the refrigerant in the second suction port (55a) is sucked into the low pressure chamber of the inner compression chamber (C32).

  Then, when the drive shaft (35) makes one revolution and again enters the state of FIG. 4 (F), the suction of the refrigerant into the low pressure chamber is completed. The low-pressure chamber becomes a high-pressure chamber in which the refrigerant is compressed, and a new low-pressure chamber is formed across the third blade (83). When the drive shaft (35) further rotates, the suction of the refrigerant is repeated in the low pressure chamber, while the volume of the high pressure chamber is reduced, and the refrigerant is compressed in the high pressure chamber. When the high pressure chamber reaches a predetermined pressure and the differential pressure from the third discharge port (56a) reaches a set value, the discharge valves (88, 89) open, and the refrigerant in the high pressure chamber passes through the third discharge port (56a). It flows out into the internal space (S1) in the casing (40).

  In the outer compression chamber (C31), refrigerant discharge is started approximately at the timing shown in FIG. 4E, and in the inner compression chamber (C32), discharge is started approximately at the timing shown in FIG. That is, the discharge timing is shifted by approximately 180 ° between the outer compression chamber (C31) and the inner compression chamber (C32). The high-pressure refrigerant that has flowed into the internal space (S1) in the casing (40) is discharged from the second discharge pipe (17). In the refrigerant circuit, the refrigerant discharged from the compressor (11) is again sucked into the compressor (11) through a condensation process, an expansion process, and an evaporation process.

  In the second compression mechanism portion (32), in FIG. 6, the rotation of the rotor (34a) is transmitted to the second piston (72) via the second eccentric portion (35c) of the drive shaft (35). Thereby, the second piston (72) revolves while swinging with respect to the first cylinder (71), and the second compression mechanism (32) performs a predetermined compression operation.

  Specifically, in the second cylinder chamber (C2), the drive shaft (35) rotates clockwise from the state shown in FIG. 6 (A) and the suction port (76) is closed by the piston (72). As the drive shaft (35) further rotates from the state and changes to the state of FIGS. 6 (B) to (A), the volume of the low-pressure chamber increases, and the refrigerant is sucked from the second suction pipe (53). It is sucked into the low pressure chamber through the port (76).

  When the drive shaft (35) rotates once and the suction port (76) is closed again by the piston (72), the suction of the refrigerant into the low pressure chamber is completed, and the refrigerant is compressed in the low pressure chamber. It becomes a high pressure chamber. At this time, a new low pressure chamber is formed across the blade (73). When the drive shaft (35) further rotates, the suction of the refrigerant is repeated in the low pressure chamber, while the volume of the high pressure chamber is reduced, and the refrigerant is compressed in the high pressure chamber. When the pressure in the high pressure chamber reaches a predetermined value and the differential pressure with respect to the discharge space (not shown) reaches a set value, the discharge valve (not shown) is opened, and the refrigerant in the high pressure chamber is discharged from the discharge port and the discharge space. It flows out to a 2nd discharge pipe (54) via (not shown).

  In the first embodiment, the suction volume (push volume) V1 of the first compression mechanism (31), the suction volume (push volume) V2 of the second compression mechanism (32), and the third compression mechanism ( The compression mechanism portions (31, 32, 33) are designed so that a relationship of V1> V2> V3 is established between the suction volume (displacement volume) V3 of (33).

(Operation of air conditioner)
Next, the operation of the air conditioner (1) will be described. The air conditioner (1) can be switched between the following cooling operation and heating operation.

(Cooling operation)
As shown in FIG. 7, when the compressor (11) is started with the four-way valve (17) set to the first position, the outdoor heat exchanger (12) is connected to the radiator in the refrigerant circuit (10). On the other hand, a two-stage compression refrigeration cycle in which the indoor heat exchanger (16) serves as an evaporator is performed. In this two-stage compression refrigeration cycle, the high pressure of the two-stage compression refrigeration cycle is higher than the critical pressure of carbon dioxide. This is the same in the heating operation described later.

  Specifically, when the compressor (11) is started, the high-pressure gas refrigerant compressed in the compressor (11) flows into the outdoor heat exchanger (12) via the four-way valve (17). In the outdoor heat exchanger (12), the high-pressure gas refrigerant exchanges heat with air and dissipates heat to be cooled.

  The refrigerant cooled in the outdoor heat exchanger (12) is depressurized to an intermediate pressure by the first expansion valve (13), and then separated into liquid refrigerant and gas refrigerant by the gas-liquid separator (14). Among these, the gas refrigerant flows between the low-stage compression mechanism and the high-stage compression mechanism of the compressor (11) through the injection pipe (20). On the other hand, the liquid refrigerant flows into the indoor heat exchanger (16) after being reduced to a low pressure in the second expansion valve (15).

  In the indoor heat exchanger (16), the refrigerant absorbs heat from the indoor air and evaporates. As a result, the room air is cooled and supplied to the room. The low-pressure gas refrigerant evaporated in the indoor heat exchanger (16) is sucked into the compressor (11) and compressed again.

(Heating operation)
In the heating operation, as shown in FIG. 8, when the compressor (11) is started with the four-way valve (17) set to the second position, the refrigerant circuit (10) causes the indoor heat exchanger (16 ) Becomes a radiator, while a two-stage compression refrigeration cycle in which the outdoor heat exchanger (12) becomes an evaporator is performed.

  Specifically, when the compressor (11) is started, the high-pressure gas refrigerant compressed in the compressor (11) flows into the indoor heat exchanger (16) via the four-way valve (17). In the indoor heat exchanger (16), the high-pressure gas refrigerant exchanges heat with room air and dissipates heat to be cooled. As a result, the room air is heated and supplied to the room.

  The refrigerant cooled in the indoor heat exchanger (16) is depressurized to an intermediate pressure by the second expansion valve (15), and then separated into liquid refrigerant and gas refrigerant by the gas-liquid separator (14). Among these, the gas refrigerant flows between the low-stage compression mechanism and the high-stage compression mechanism of the compressor (11) through the injection pipe (20). On the other hand, the liquid refrigerant is reduced to a low pressure in the first expansion valve (13) and then flows into the outdoor heat exchanger (12).

  In the outdoor heat exchanger (12), the refrigerant absorbs heat from the outdoor air and evaporates. The low-pressure gas refrigerant evaporated in the outdoor heat exchanger (12) is sucked into the compressor (11) and compressed again.

(Control of suction volume ratio changing means)
In the first embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio changing means (2) changes the suction volume ratio Vr. Specifically, the first three-way valve (18) and the second three-way valve (19) constituting the switching mechanism are switched to the first position or the second position according to a change in operating conditions by a controller (not shown). It is done. Thereby, the connection relationship of the three compression mechanism parts (31, 32, 33) is changed, and the suction volume ratio Vr is changed.

  More specifically, when both the first three-way valve (18) and the second three-way valve (19) are switched to the second position, the lower stage of the three compression mechanisms (31, 32, 33) It will be in the 1st state where the 1st compression mechanism part (31) used as a compression mechanism and the 2nd compression mechanism part (32) are connected in series. On the other hand, when both the first three-way valve (18) and the second three-way valve (19) are switched to the first position, the first compression mechanism (31) and the second compression mechanism (32) are connected in parallel. This is the second state. Moreover, in this Embodiment 1, when switching to air_conditionaing | cooling operation, a 1st three-way valve (18) and a 2nd three-way valve (19) are switched to a 2nd position, and it will be in the said 1st state, and heating operation is carried out. At the time of switching, the first three-way valve (18) and the second three-way valve (19) are switched to the first position to be in the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 7, in the first state, the first communication pipe (26) and the second communication pipe (27) communicate with each other, and the second communication pipe (27) and the third communication pipe (28 ).

  Thus, the refrigerant in the low pressure state of the low pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31). The refrigerant compressed in the first compression mechanism section (31) passes through the first communication pipe (26), the second communication pipe (27), and the third communication pipe (28) to the second compression mechanism section (32). Inhaled and compressed in the second compression mechanism (32) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the second compression mechanism section (32) is sucked into the third compression mechanism section (33) through the fourth communication pipe (29), and the third compression mechanism section (33). And compressed to a high pressure state. In addition, the gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) flows into the middle part of the fourth communication pipe (29) through the injection pipe (20). Therefore, the refrigerant flowing through the fourth connecting pipe (29) is cooled by the gas refrigerant flowing from the injection pipe (20) and then sucked into the third compression mechanism section (33).

  The refrigerant compressed to the high pressure state in the third compression mechanism section (33) is discharged into the internal space (S1) of the casing (40), and eventually the high pressure gas pipe (21 through the high pressure discharge pipe (56). ).

  Thus, in the first state, the first compression mechanism portion (31) and the second compression mechanism portion (32) are connected in series and used as the low-stage compression mechanism, while the third compression mechanism portion (33). Is used as a high-stage compression mechanism. Thereby, in the first state, the suction volume of the low-stage compression mechanism becomes the suction volume V1 of the first compression mechanism part (31), and the suction volume of the high-stage compression mechanism becomes the suction volume of the third compression mechanism part (33). The suction volume is V3. Therefore, the suction volume ratio Vr is V3 / V1.

  On the other hand, in the second state, the first connecting pipe (26) and the fourth connecting junction pipe (29a) connected to the middle part of the fourth connecting pipe (29) communicate with each other, and the low-pressure gas pipe ( 25) The low-pressure gas branch pipe (25a) connected to the midway part and the third connecting pipe (28) communicate with each other.

  As a result, the low-pressure gas state refrigerant in the low-pressure gas pipe (25) is sucked into the first compression mechanism (31), and a part of the low-pressure gas is connected to the midway part of the low-pressure gas pipe (25). The air is sucked into the second compression mechanism section (32) through the branch pipe (25a) and the third communication pipe (28). Then, the first compression mechanism portion (31) and the second compression mechanism portion (32) are respectively compressed until they reach an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism section (31) passes through the first communication pipe (26) and the fourth communication junction pipe (29a), and is in the middle of the fourth communication pipe (29). Flow into. On the other hand, the refrigerant compressed to the intermediate pressure state in the second compression mechanism part (32) flows into the fourth connecting pipe (29) and joins with the refrigerant flowing in from the fourth connecting joining pipe (29a). The air is sucked into the third compression mechanism part (33) and compressed in the third compression mechanism part (33) until a high pressure state is reached. The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed downstream of the fourth connecting pipe (29a) of the fourth connecting pipe (29) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the fourth connecting pipe (29) is cooled by the gas refrigerant flowing from the injection pipe (20) and then sucked into the third compression mechanism section (33).

  The refrigerant compressed to the high pressure state in the third compression mechanism section (33) is discharged into the internal space (S1) of the casing (40), and eventually the high pressure gas pipe (21 through the high pressure discharge pipe (56). ).

  Thus, in the second state, the first compression mechanism portion (31) and the second compression mechanism portion (32) are connected in parallel and used as the low-stage compression mechanism, while the third compression mechanism portion (33). Is used as a high-stage compression mechanism. As a result, in the second state, the suction volume of the low-stage compression mechanism is the sum of the suction volume V1 of the first compression mechanism section (31) and the suction volume V2 of the second compression mechanism section (32). The suction volume of the compression mechanism is the suction volume V3 of the third compression mechanism section (33). Therefore, the suction volume ratio Vr is V3 / (V1 + V2).

  Here, in the compressor (11) of the air conditioner (1), three compression mechanisms (31, 32, 33) are mechanically connected to one drive shaft (35). Thereby, for example, when the suction volume ratio Vr is set to a suitable value in the cooling operation and the heating operation is performed without changing the suction volume ratio Vr, the value of the intermediate pressure is intermediate between the low pressure and the high pressure in the heating operation. On the other hand, when the suction volume ratio Vr is set to a suitable value in the heating operation and the cooling operation is performed without changing the suction volume ratio Vr, the value of the intermediate pressure between the low pressure and the high pressure is set in the cooling operation. Higher than the middle. Therefore, if the suction volume ratio Vr is set so that the intermediate pressure becomes an average value between the low pressure and the high pressure in one of the operating conditions, the intermediate pressure greatly deviates from the average value of the low pressure and the high pressure in the other operating condition. Will end up.

  However, in the present air conditioner (1), as described above, when switching to the cooling operation, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Thereby, since the compression ratio in the low-stage side compression mechanism becomes small, the intermediate pressure is lowered and becomes a value close to the average value of the low pressure and the high pressure. As a result, a high COP can be obtained in the cooling operation. Further, since the intermediate pressure is reduced, the amount of gas injection from the injection pipe (20) as the cooling means becomes relatively large. Thereby, since the refrigerant | coolant between a low stage side compression mechanism and a high stage side compression mechanism is cooled more, the input of a compressor (11) can be reduced.

  On the other hand, in the present air conditioner (1), when switching to the heating operation, the suction volume ratio Vr is changed by the suction volume ratio changing means (2) so as to be reduced. As a result, the compression ratio in the low-stage side compression mechanism increases, so that the intermediate pressure rises and becomes a value close to the average value of the low pressure and the high pressure. As a result, a high COP can be obtained in the heating operation. In addition, as the intermediate pressure increases, the amount of gas injection from the injection pipe (20) as the cooling means becomes relatively small. As a result, the temperature of the refrigerant sucked into the high-stage compression mechanism is prevented from being reduced as much as possible, and the amount of heat absorbed from the outdoor air can be increased by increasing the refrigerant flow rate of the outdoor heat exchanger (12). Therefore, both reduction of the input of the compressor (11) and improvement of the heating capacity can be achieved.

  From the above, when the first three-way valve (18) and the second three-way valve (19) constituting the switching mechanism of the suction volume ratio changing means (2) are switched from the first state to the second state, the suction volume ratio While Vr decreases, the suction volume ratio Vr increases when the second state is switched to the first state.

-Effect of Embodiment 1-
As described above, according to the air conditioner (1), since the suction volume ratio changing means (2) is provided, a high COP can be obtained by changing the suction volume ratio Vr in accordance with a change in operating conditions. Thus, the intermediate pressure can be varied (increased or decreased). Therefore, a high COP can be obtained regardless of changes in operating conditions.

  Moreover, according to this air conditioning apparatus (1), since three compression mechanism parts are provided, the three compression mechanism parts (31, 32, 33) can be obtained without changing the shape of the cylinder chamber of the compression mechanism part. By changing the connection relationship, the suction volume ratio Vr can be easily changed.

  Further, according to the air conditioner (1), the first three-way valve (18) and the second three-way valve (19) constituting the switching mechanism of the suction volume ratio changing means (2) serve as a low-stage compression mechanism. The suction volume ratio Vr can be easily changed by switching the connection relationship between the first compression mechanism section (31) and the second compression mechanism section (32) used in series or in parallel.

  Furthermore, in the refrigerant circuit (10) of the air conditioner (1), carbon dioxide is used as the refrigerant. Thus, in the two-stage compression refrigeration cycle using carbon dioxide as a refrigerant, there is a problem that heat dissipation loss is large and it is difficult to obtain a high coefficient of performance (COP). Therefore, the significance of improving the COP by providing the suction volume ratio changing means (2) is further increased.

  In addition, since the two-cylinder chamber type compression mechanism (31, 33) has a characteristic that the torque fluctuation of the one-cylinder chamber type is small, all of the plurality of compression mechanism units are one-cylinder chamber type compression mechanism units. Vibration and noise can be suppressed compared to the constructed one.

<< Embodiment 2 of the Invention >>
The air conditioner (1) of Embodiment 2 shown in FIGS. 9 and 10 will be described. Hereinafter, differences from the first embodiment will be described.

-Overall configuration-
In the second embodiment, the suction volume ratio changing means (2) is a first state in which the second compression mechanism part (32) and the third compression mechanism part (33) used as the high-stage side compression mechanism are connected in parallel. And a switching mechanism for switching to a second state connected in series. The switching mechanism includes a third three-way valve (90) and a fourth three-way valve (91). The third three-way valve (90) and the fourth three-way valve (91) have first to third ports (P1, P2, P3), respectively, and the first port (P1) and the second port (P2) communicate with each other. The first position is switched to the second position where the second port (P2) and the third port (P3) communicate with each other.

  Also in Embodiment 2, the high-pressure discharge pipe (56) is connected to the first port (P1) of the four-way valve (17) via the high-pressure gas pipe (21). One end of the low pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17). The other end of the low pressure gas pipe (25) is connected to the first suction pipe (51).

  One end of the first connecting pipe (26) is connected to the first discharge pipe (52), and the other end of the first connecting pipe (26) is connected to the second suction pipe (53). One end of the first connecting branch pipe (26a) is connected to the middle part of the first connecting pipe (26), and the other end of the first connecting branch pipe (26a) is connected to the second three-way valve (19). Connected to the first port (P1). One end is connected to the gas-liquid separator (14) on the first discharge pipe (52) side of the connection part of the first connection branch pipe (26a) in the middle of the first connection pipe (26). The other end of the injection pipe (20) is connected. The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  One end of the second communication pipe (27) is connected to the second discharge pipe (54), and the other end of the second communication pipe (27) is connected to the second port (P2 of the third three-way valve (90)). )It is connected to the. One end of a high pressure gas junction pipe (21a) is connected to the first port (P1) of the third three-way valve (90), and the other end of the high pressure gas junction pipe (21a) is connected to the high pressure gas pipe (21). It is connected to the middle part. Further, one end of the third communication pipe (28) is connected to the third port (P3) of the third three-way valve (90), and the other end of the third communication pipe (28) is connected to the fourth three-way valve (91). ) To the third port (P3). One end of a fourth connecting pipe (29) is connected to the second port (P2) of the fourth three-way valve (91), and the other end of the fourth connecting pipe (29) is connected to the third suction pipe (55). It is connected.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

-Driving action-
Next, the operation of the air conditioner (1) will be described. Also in the second embodiment, the air conditioner (1) can be switched between a cooling operation (see FIG. 9) and a heating operation (see FIG. 10). In addition, since it is the same as that of Embodiment 1 about air_conditionaing | cooling operation operation and heating operation operation, description is abbreviate | omitted.

(Control of suction volume ratio changing means)
Also in the second embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Specifically, the third three-way valve (90) and the fourth three-way valve (91) constituting the switching mechanism are switched to the first position or the second position according to a change in operating conditions by a controller (not shown). It is done. Thereby, the connection relation of the three compression mechanism parts (31, 32, 33) is switched, and the suction volume ratio Vr is changed.

  More specifically, when both the third three-way valve (90) and the fourth three-way valve (91) are switched to the first position, the higher stage of the three compression mechanisms (31, 32, 33) It will be in the 1st state where the 2nd compression mechanism part (32) used as a compression mechanism and the 3rd compression mechanism part (33) are connected in parallel. On the other hand, when both the third three-way valve (90) and the fourth three-way valve (91) are switched to the second position, the second compression mechanism part (32) and the third compression mechanism part (33) are connected in series. This is the second state. In the second embodiment, when switching to the cooling operation, the third three-way valve (90) and the fourth three-way valve (91) are switched to the first position to be in the first state and switched to the heating operation. In this case, the third three-way valve (90) and the fourth three-way valve (91) are switched to the second position to be in the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 9, in the first state, the first connecting branch pipe (26a) and the fourth connecting pipe (29) communicate with each other, and the second connecting pipe (27) and the high-pressure gas junction pipe ( 21a) is communicated with.

  As a result, the refrigerant in the low pressure state of the low pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism part (31) is sucked into the second compression mechanism part (32) through the first communication pipe (26), and a part thereof is the first. The air is sucked into the third compression mechanism (33) through the first connecting branch pipe (26a) and the fourth connecting pipe (29) connected to the middle part of the one connecting pipe (26). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed upstream of the first communication branch pipe (26a) of the first communication pipe (26) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the first communication pipe (26) is sucked into the third compression mechanism section (33) after being cooled by the gas refrigerant flowing from the injection pipe (20).

  The refrigerant sucked into the second compression mechanism part (32) and the third compression mechanism part (33) is in a high pressure state in the second compression mechanism part (32) and the third compression mechanism part (33), respectively. Compressed. And the refrigerant | coolant of a 2nd compression mechanism part (32) flows in into the middle part of a high pressure gas pipe (21) through a 2nd connecting pipe (27) and a high pressure gas confluence | merging pipe (21a). On the other hand, the refrigerant in the third compression mechanism (33) is discharged into the internal space (S1) of the casing (40) and eventually flows into the high-pressure gas pipe (21) via the high-pressure discharge pipe (56).

  Thus, in the first state, the first compression mechanism (31) is used as the low-stage compression mechanism, while the second compression mechanism (32) and the third compression mechanism (33) are connected in parallel. Used as a high-stage compression mechanism. As a result, in the first state, the suction volume of the low-stage compression mechanism is the suction volume V1 of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism is that of the second compression mechanism section (32). This is the sum of the suction volume V2 and the suction volume V3 of the third compression mechanism (33). Therefore, the suction volume ratio Vr is (V2 + V3) / V1.

  On the other hand, in the second state, the second communication pipe (27) and the third communication pipe (28) communicate with each other, and the third communication pipe (28) and the fourth communication pipe (29) communicate with each other. The

  As a result, the refrigerant in the low pressure state of the low pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism section (31) is sucked into the second compression mechanism section (32) through the first connecting pipe (26), and the second compression mechanism section ( 32) is compressed. The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) flows into the middle part of the first communication pipe (26) through the injection pipe (20). Therefore, the refrigerant flowing through the first communication pipe (26) is sucked into the second compression mechanism section (32) after being cooled by the gas refrigerant flowing in from the injection pipe (20).

  The refrigerant compressed in the second compression mechanism section (32) passes through the second communication pipe (27), the third communication pipe (28), and the fourth communication pipe (29) to the third compression mechanism section (33). Inhaled and compressed in the third compression mechanism (33) until it reaches a high pressure state.

  The refrigerant compressed to the high pressure state in the third compression mechanism section (33) is discharged into the internal space (S1) of the casing (40), and eventually the high pressure gas pipe (21 through the high pressure discharge pipe (56). ).

  Thus, in the second state, the first compression mechanism (31) is used as the low-stage compression mechanism, while the second compression mechanism (32) and the third compression mechanism (33) are connected in series. Used as a high-stage compression mechanism. Thereby, in the second state, the suction volume of the low-stage compression mechanism becomes the suction volume V1 of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism becomes the suction volume of the second compression mechanism section (32). The suction volume V2. Therefore, the suction volume ratio Vr is V2 / V1.

  From the above, when the third three-way valve (90) and the fourth three-way valve (91) constituting the switching mechanism of the suction volume ratio changing means (2) are switched from the first state to the second state, the suction volume ratio While Vr decreases, the suction volume ratio Vr increases when the second state is switched to the first state.

-Effect of Embodiment 2-
As described above, also in the air conditioner (1) of the second embodiment, the third three-way valve (90) and the fourth three-way valve (91) constituting the switching mechanism of the suction volume ratio changing means (2) The suction volume ratio Vr can be easily changed by switching the connection relationship between the second compression mechanism section (32) and the third compression mechanism section (33) used as the compression mechanism in series or in parallel.

<< Embodiment 3 of the Invention >>
The air conditioner (1) of Embodiment 2 shown in FIGS. 11 and 12 will be described. Hereinafter, differences from the first embodiment will be described.

-Overall configuration-
In the third embodiment, the third compression mechanism (33) is configured in substantially the same manner as the second compression mechanism (32) in the first embodiment. Specifically, the discharge space and the discharge port of the third compression mechanism (33) formed in the front head (37) in the first embodiment are formed in the third cylinder (81) (not shown). A discharge valve is attached to the discharge port, and a third discharge pipe (57) is connected to the discharge space.

  The said 3rd discharge pipe (57) is provided so that the inside and outside of a casing (40) may penetrate like a 1st discharge pipe (52) and a 2nd discharge pipe (54). The third discharge pipe (57) is provided above the second discharge pipe (54). Further, a high-pressure connecting pipe (58) is provided above the third discharge pipe (57) so as to penetrate the inside and outside of the casing (40). The high-pressure connecting pipe (58) is provided such that an inner end opens between the electric motor (34) and the three compression mechanism parts (31, 32, 33).

  In the third embodiment, the suction volume ratio changing means (2) includes the first compression mechanism part (31) and the second compression mechanism part having different suction volumes among the three compression mechanism parts (31, 32, 33). (32) A switching mechanism for changing the connection relationship is provided. The switching mechanism includes a second four-way valve (92) and a third four-way valve (93). The second four-way valve (92) and the third four-way valve (93) have first to fourth ports (P1, P2, P3, P4), respectively, and the first port (P1) and the second port (P2) Can be switched to a first position at which the third port (P3) and the fourth port (P4) communicate with each other.

  Also in Embodiment 3, the high-pressure discharge pipe (56) is connected to the first port (P1) of the four-way valve (17) via the high-pressure gas pipe (21). One end of the low pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17). The other end of the low pressure gas pipe (25) is connected to the third suction pipe (55). One end of the low-pressure gas branch pipe (25a) is connected to the middle portion of the low-pressure gas pipe (25), and the other end of the low-pressure gas branch pipe (25a) is the first port of the third four-way valve (93). Connected to (P1).

  One end of the first communication pipe (26) is connected to the fourth port (P4) of the third four-way valve (93), and the other end of the first communication pipe (26) is connected to the first suction pipe (51). It is connected to the. One end of the second communication pipe (27) is connected to the second port (P2) of the third four-way valve (93), and the other end of the second communication pipe (27) is connected to the second suction pipe ( 53) is connected.

  One end of a third connecting pipe (28) is connected to the first discharge pipe (52), and the other end of the third connecting pipe (28) is connected to the third port (P3) of the second four-way valve (92). It is connected to the. The second discharge pipe (54) is connected to one end of a fourth communication pipe (29), and the other end of the fourth communication pipe (29) is connected to the first port (92) of the second four-way valve (92). Connected to P1). Further, one end of a fifth communication pipe (30) is connected to the third discharge pipe (57), and the other end of the fifth communication pipe (30) is connected to the third port (93) of the third four-way valve (93). Connected to P3).

  One end of a fifth connecting / merging pipe (30a) is connected to the middle part of the fifth connecting pipe (30), and the other end of the fifth connecting / merging pipe (30a) is connected to the second four-way valve (92). It is connected to the second port (P2). One end is connected to the gas-liquid separator (14) on the third four-way valve (93) side of the middle of the fifth connecting pipe (30) from the connecting part of the fifth connecting junction pipe (30a). The other end of the injection pipe (20) is connected. The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  One end of a sixth connecting pipe (59) is connected to the fourth port (P4) of the second four-way valve (92), and the other end of the sixth connecting pipe (59) is connected to the high pressure connecting pipe (58). It is connected.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

-Driving action-
Next, the operation of the air conditioner (1) will be described. Also in Embodiment 3, the air conditioner (1) can be switched between a cooling operation (see FIG. 11) and a heating operation (see FIG. 12). In addition, since it is the same as that of Embodiment 1 about air_conditionaing | cooling operation operation and heating operation operation, description is abbreviate | omitted.

(Control of suction volume ratio changing means)
Also in the third embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Specifically, the second four-way valve (92) and the third four-way valve (93) constituting the switching mechanism are switched to the first position or the second position according to a change in operating conditions by a controller (not shown). It is done. Thereby, the connection relation of the three compression mechanism parts (31, 32, 33) is switched, and the suction volume ratio Vr is changed.

  Specifically, when both the second four-way valve (92) and the third four-way valve (93) are switched to the first position, the second compression mechanism portion (32) and the third compression mechanism portion (33) are arranged in parallel. The first compression mechanism section (31) is in a first state used as a high-stage compression mechanism, while being used as a low-stage compression mechanism. On the other hand, when the second four-way valve (92) and the third four-way valve (93) are switched to the second position, the first compression mechanism (31) and the third compression mechanism (33) are connected in parallel. While being used as a low-stage compression mechanism, the second compression mechanism section (32) is in a second state used as a high-stage compression mechanism. That is, the connection relationship between the first compression mechanism (31) and the second compression mechanism (32) is changed between the first state and the second state.

  In the third embodiment, when switching to the cooling operation, the second four-way valve (92) and the third four-way valve (93) are switched to the first position to be in the first state, and switched to the heating operation. In this case, the second four-way valve (92) and the third four-way valve (93) are switched to the second position to be in the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 11, in the first state, the low pressure gas branch pipe (25a) and the second communication pipe (27) communicate with each other, and the fifth communication pipe (30) and the first communication pipe (26) Are communicated, the fourth communication pipe (29) and the fifth communication junction pipe (30a) are communicated, and the third communication pipe (28) and the sixth communication pipe (59) are communicated.

  Thus, the low-pressure gas state refrigerant in the low-pressure gas pipe (25) is sucked into the third compression mechanism part (33), and a part of the low-pressure gas is connected to the middle part of the low-pressure gas pipe (25). The air is sucked into the second compression mechanism (32) through the branch pipe (25a) and the second communication pipe (27). Then, the second compression mechanism section (32) and the third compression mechanism section (33) are respectively compressed until they reach an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the second compression mechanism section (32) passes through the fourth connecting pipe (29) and the fifth connecting junction pipe (30a), and the middle section of the fifth connecting pipe (30). Flow into. On the other hand, the refrigerant compressed to the intermediate pressure state in the third compression mechanism section (33) flows into the fifth communication pipe (30) and merges with the refrigerant flowing in from the fifth communication junction pipe (30a). The combined refrigerant is sucked into the first compression mechanism part (31) through the first communication pipe (26), and is compressed in the first compression mechanism part (31) until a high pressure state is reached. The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed downstream of the fifth connecting pipe (30a) of the fifth connecting pipe (30) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the fifth communication pipe (30) is cooled by the gas refrigerant flowing from the injection pipe (20) and then sucked into the first compression mechanism section (31).

  The refrigerant compressed to the high pressure state in the first compression mechanism (31) enters the internal space (S1) of the casing (40) through the third connecting pipe (28) and the sixth connecting pipe (59). It is discharged and eventually flows into the high-pressure gas pipe (21) through the high-pressure discharge pipe (56).

  Thus, in the first state, the second compression mechanism part (32) and the third compression mechanism part (33) are connected in parallel and used as the low-stage compression mechanism, while the first compression mechanism part (31) Is used as a high-stage compression mechanism. As a result, in the first state, the suction volume of the low-stage compression mechanism is the sum of the suction volume V2 of the second compression mechanism section (32) and the suction volume V3 of the third compression mechanism section (33). The suction volume of the compression mechanism is the suction volume V1 of the first compression mechanism section (31). Therefore, the suction volume ratio Vr is V1 / (V2 + V3).

  On the other hand, in the second state, the low pressure gas branch pipe (25a) and the first communication pipe (26) are communicated, the fifth communication pipe (30) and the second communication pipe (27) are communicated, The 4th communication pipe (29) and the 6th communication pipe (59) are connected, and the 3rd communication pipe (28) and the 5th communication junction pipe (30a) are connected.

  Thus, the low-pressure gas state refrigerant in the low-pressure gas pipe (25) is sucked into the third compression mechanism part (33), and a part of the low-pressure gas is connected to the middle part of the low-pressure gas pipe (25). The air is sucked into the first compression mechanism (31) through the branch pipe (25a) and the first communication pipe (26). Then, the first compression mechanism portion (31) and the third compression mechanism portion (33) are respectively compressed until they reach an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism section (31) passes through the third connecting pipe (28) and the fifth connecting junction pipe (30a), and is in the middle of the fifth connecting pipe (30). Flow into. On the other hand, the refrigerant compressed to the intermediate pressure state in the third compression mechanism section (33) flows into the fifth communication pipe (30) and merges with the refrigerant flowing in from the fifth communication junction pipe (30a). The merged refrigerant is sucked into the second compression mechanism part (32) through the second communication pipe (27) and compressed in the second compression mechanism part (32) until a high pressure state is reached. The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed downstream of the fifth connecting pipe (30a) of the fifth connecting pipe (30) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the fifth communication pipe (30) is cooled by the gas refrigerant flowing from the injection pipe (20) and then sucked into the second compression mechanism section (32).

  The refrigerant compressed to the high pressure state in the second compression mechanism (32) enters the internal space (S1) of the casing (40) through the fourth connecting pipe (29) and the sixth connecting pipe (59). It is discharged and eventually flows into the high-pressure gas pipe (21) through the high-pressure discharge pipe (56).

  Thus, in the second state, the first compression mechanism portion (31) and the third compression mechanism portion (33) are connected in parallel and used as the low-stage compression mechanism, while the second compression mechanism portion (32) Is used as a high-stage compression mechanism. As a result, in the second state, the suction volume of the low-stage compression mechanism is the sum of the suction volume V1 of the first compression mechanism section (31) and the suction volume V3 of the third compression mechanism section (33). The suction volume of the compression mechanism is the suction volume V2 of the second compression mechanism section (32). Therefore, the suction volume ratio Vr is V2 / (V1 + V3).

  As described above, when the second four-way valve (92) and the third four-way valve (93) constituting the switching mechanism of the suction volume ratio changing means (2) are switched from the first state to the second state, the suction volume ratio is changed. While Vr decreases, the suction volume ratio Vr increases when the second state is switched to the first state.

-Effect of Embodiment 3-
As described above, also in the air conditioner (1) of the third embodiment, the suction volume can be reduced by the second four-way valve (92) and the third four-way valve (93) constituting the switching mechanism of the suction volume ratio changing means (2). The suction volume ratio Vr can be easily changed by changing the connection relationship between the two different compression mechanisms (31, 32).

<< Embodiment 4 of the Invention >>
The air conditioner (1) of Embodiment 2 shown in FIGS. 13 and 14 will be described. Hereinafter, differences from the first embodiment will be described.

-Overall configuration-
In the fourth embodiment, the suction volume ratio changing means (2) includes the first state in which the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33), and the three compression mechanism portions. The refrigerant is compressed in the two compression mechanism portions (31, 33) of (31, 32, 33), while the refrigerant passes through the remaining one compression mechanism portion (32) without being compressed. A switching mechanism for switching between the two states.

  Specifically, the switching mechanism is constituted by a fifth three-way valve (94). The fifth three-way valve (94) includes first to third ports (P1, P2, P3), a first position where the first port (P1) and the second port (P2) communicate with each other, The port (P2) and the third port (P3) can be switched to a second position where they communicate.

  Also in Embodiment 4, the high-pressure discharge pipe (56) is connected to the first port (P1) of the four-way valve (17) via the high-pressure gas pipe (21). One end of the low pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17). The other end of the low pressure gas pipe (25) is connected to the first suction pipe (51).

  One end of the first connecting pipe (26) is connected to the first discharge pipe (52), and the other end of the first connecting pipe (26) is connected to the second suction pipe (53). One end of the first connecting junction pipe (26a) is connected to the middle part of the first connecting pipe (26), and the other end of the first connecting branch pipe (26a) is connected to the fifth three-way valve (94). It is connected to the third port (P3). In addition, one end of the first connection branch pipe (26b) is connected to the second suction pipe (53) side of the connection part of the first connection junction pipe (26a) in the middle of the first connection pipe (26). The other end of the first connecting branch pipe (26b) is connected to the third suction pipe (55). Further, one end of the first connecting pipe (26) is connected between the connecting portion of the first connecting junction pipe (26a) and the connecting portion of the first connecting branch pipe (26b). ) Is connected to the other end of the injection pipe (20). The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  One end of a second connecting pipe (27) is connected to the second discharge pipe (54), and the other end of the second connecting pipe (27) is connected to the second port (P2 of the fifth three-way valve (94). )It is connected to the. One end of a high pressure gas junction pipe (21a) is connected to the first port (P1) of the fifth three-way valve (94), and the other end of the high pressure gas junction pipe (21a) is connected to the high pressure gas pipe (21). It is connected to the middle part.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

-Driving action-
Next, the operation of the air conditioner (1) will be described. Also in Embodiment 4, the air conditioner (1) can be switched between a cooling operation (see FIG. 13) and a heating operation (see FIG. 14). In addition, since it is the same as that of Embodiment 1 about air_conditionaing | cooling operation operation and heating operation operation, description is abbreviate | omitted.

(Control of suction volume ratio changing means)
Also in the fourth embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Specifically, when the operating condition changes, the controller (not shown) switches the fifth three-way valve (94) constituting the switching mechanism to the first position or the second position, and the suction volume ratio Vr is changed.

  More specifically, when the fifth three-way valve (94) is switched to the first position, the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33). It becomes a state. On the other hand, when the fifth three-way valve (94) is switched to the second position, the suction side and the discharge side of the second compression mechanism part (32) become equal to each other in the pressure state, and the refrigerant becomes the second compression mechanism part ( 32) passes through uncompressed, while the first compression mechanism (31) and the third compression mechanism (33) are in a second state where the refrigerant is compressed. In the fourth embodiment, the fifth three-way valve (94) is switched to the first position when switched to the cooling operation to be in the first state, and the fifth three-way valve is switched to the heating operation. (94) is switched to the second position to enter the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 13, in the first state, the second communication pipe (27) and the high-pressure gas junction pipe (21a) communicate with each other.

  As a result, the refrigerant in the low pressure state of the low pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism part (31) is sucked into the second compression mechanism part (32) through the first communication pipe (26), and a part thereof is the first. The air is sucked into the third compression mechanism part (33) through the first connection branch pipe (26b) connected to the middle part of the one connection pipe (26). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed upstream of the first communication branch pipe (26b) of the first communication pipe (26) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the first communication pipe (26) is sucked into the second compression mechanism part (32) and the third compression mechanism part (33) after being cooled by the gas refrigerant flowing in from the injection pipe (20). The

  The refrigerant sucked into the second compression mechanism part (32) and the third compression mechanism part (33) is in a high pressure state in the second compression mechanism part (32) and the third compression mechanism part (33), respectively. Compressed. And the refrigerant | coolant of a 2nd compression mechanism part (32) flows in into the middle part of a high pressure gas pipe (21) through a 2nd connecting pipe (27) and a high pressure gas confluence | merging pipe (21a). On the other hand, the refrigerant in the third compression mechanism (33) is discharged into the internal space (S1) of the casing (40) and eventually flows into the high-pressure gas pipe (21) via the high-pressure discharge pipe (56).

  Thus, in the first state, the first compression mechanism (31) is used as the low-stage compression mechanism, while the second compression mechanism (32) and the third compression mechanism (33) are connected in parallel. Used as a high-stage compression mechanism. As a result, in the first state, the suction volume of the low-stage compression mechanism is the suction volume V1 of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism is that of the second compression mechanism section (32). This is the sum of the suction volume V2 and the suction volume V3 of the third compression mechanism (33). Therefore, the suction volume ratio Vr is (V2 + V3) / V1.

  On the other hand, in the second state, the second communication pipe (27) communicates with the first communication junction pipe (26a). As described above, the first connecting / merging pipe (26a) is connected to the first connecting pipe (26), and the first connecting pipe (26) is connected to the second suction pipe (53). The second communication pipe (27) is connected to the second discharge pipe (54). Therefore, in the second state, the suction side and the discharge side of the second compression mechanism section (32) are in communication with each other and are in an equal pressure state. Therefore, the refrigerant flows in the three compression mechanisms (31, 32, 33) are as follows.

  The refrigerant in the low-pressure state of the low-pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism part (31) flows into the second compression mechanism part (32) through the first connecting pipe (26), and a part thereof is the first. The air is sucked into the third compression mechanism part (33) through the first connection branch pipe (26b) connected to the middle part of the communication pipe (26). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed upstream of the first communication branch pipe (26b) of the first communication pipe (26) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the first communication pipe (26) is cooled by the gas refrigerant flowing from the injection pipe (20), and then flows into the second compression mechanism section (32) and the third compression mechanism section (33). Inhaled.

  The refrigerant flowing into the second compression mechanism part (32) passes through the inside of the second compression mechanism part (32) without being compressed in the second compression mechanism part (32), and the second communication pipe (27). And it flows into the middle part of the 1st connecting pipe (26) through the 1st connecting pipe (26a).

  On the other hand, the refrigerant sucked into the third compression mechanism part (33) is compressed in the third compression mechanism part (33) until it reaches a high pressure state. And the refrigerant | coolant compressed until it became a high pressure state in the 3rd compression mechanism part (33) is discharged by the internal space (S1) of a casing (40), and a high pressure gas pipe is finally passed through a high pressure discharge pipe (56). Flows into (21).

  Thus, in the second state, the first compression mechanism (31) is used as the low-stage compression mechanism and the third compression mechanism (33) is used as the high-stage compression mechanism, while the second compression mechanism. The part (32) is not used as any compression mechanism. Thus, in the second state, the suction volume of the low-stage compression mechanism becomes the suction volume V1 of the first compression mechanism part (31), and the suction volume of the high-stage compression mechanism becomes the suction volume of the third compression mechanism part (33). The suction volume is V3. Therefore, the suction volume ratio Vr is V3 / V1.

  As described above, the suction volume ratio Vr becomes smaller when the fifth state is switched from the first state to the second state by the fifth three-way valve (94) constituting the switching mechanism of the suction volume ratio changing means (2). When the state is switched from the first state to the first state, the suction volume ratio Vr increases.

-Effect of Embodiment 4-
As described above, also in the air conditioner (1) of the fourth embodiment, the three compression mechanism parts (31, 32, 33) are provided by the fifth three-way valve (94) constituting the switching mechanism of the suction volume ratio changing means (2). ) In the first state where the refrigerant is compressed in all the compression mechanism parts and in two compression mechanism parts (31, 33) of the three compression mechanism parts (31, 32, 33), the refrigerant is compressed. On the other hand, the suction volume ratio Vr can be easily changed by switching between the second state in which the refrigerant passes without being compressed in the remaining one compression mechanism (32).

<< Embodiment 5 of the Invention >>
The air conditioner (1) of Embodiment 5 shown in FIGS. 15 and 16 will be described. Hereinafter, differences from the first embodiment will be described.

-Overall configuration-
In the fifth embodiment, the third compression mechanism (33) is configured in substantially the same manner as the second compression mechanism (32) in the first embodiment. Specifically, the discharge space and discharge port of the third compression mechanism (33) formed in the front head (37) in the first embodiment are formed in the third cylinder (81) (not shown). A discharge valve is attached to the discharge port, and a third discharge pipe (57) is connected to the discharge space.

  The said 3rd discharge pipe (57) is provided so that the inside and outside of a casing (40) may penetrate like a 1st discharge pipe (52) and a 2nd discharge pipe (54). The third discharge pipe (57) is provided above the second discharge pipe (54). Further, a high-pressure connecting pipe (58) is provided above the third discharge pipe (57) so as to penetrate the inside and outside of the casing (40). The high-pressure connecting pipe (58) is provided such that an inner end opens between the electric motor (34) and the three compression mechanism parts (31, 32, 33).

  In the fifth embodiment, the suction volume ratio changing means (2) includes the first state in which the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33) and the three compression modes. The refrigerant is compressed in the two compression mechanism parts (31, 32) of the mechanism parts (31, 32, 33), while the refrigerant passes through the remaining one compression mechanism part (33) without being compressed. A switching mechanism for switching to the second state is provided.

  Specifically, the switching mechanism is constituted by a sixth three-way valve (95). The sixth three-way valve (95) includes first to third ports (P1, P2, P3), a first position where the first port (P1) and the second port (P2) communicate with each other, The port (P2) and the third port (P3) can be switched to a second position where they communicate.

  Also in Embodiment 5, the high-pressure discharge pipe (56) is connected to the first port (P1) of the four-way valve (17) via the high-pressure gas pipe (21). One end of the low pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17). The other end of the low pressure gas pipe (25) is connected to the first suction pipe (51). One end of the low-pressure gas branch pipe (25a) is connected to the middle part of the low-pressure gas pipe (25), and the other end of the low-pressure gas branch pipe (25a) is the third port of the sixth three-way valve (95). (P3) connected.

  One end of the first connecting pipe (26) is connected to the first discharge pipe (52), and the other end of the first connecting pipe (26) is connected to the second suction pipe (53). One end of the first connecting / merging pipe (26a) is connected to the middle part of the first connecting pipe (26), and the other end of the first connecting / merging pipe (26a) is connected to the third discharge pipe (57). Has been. Further, one end of the first connection branch pipe (26b) is connected to the second suction pipe (53) side of the connection portion of the first connection pipe (26) of the first connection junction pipe (26a). The other end of the one connecting branch pipe (26b) is connected to the first port (P1) of the sixth three-way valve (95). Further, one end of the first connecting pipe (26) is connected between the connecting portion of the first connecting junction pipe (26a) and the connecting portion of the first connecting branch pipe (26b). ) Is connected to the other end of the injection pipe (20). The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  One end of the second communication pipe (27) is connected to the second port (P2) of the sixth three-way valve (95), and the other end of the second communication pipe (27) is connected to the third suction pipe (55). It is connected. Further, one end of a third communication pipe (28) is connected to the second discharge pipe (54), and the other end of the third communication pipe (28) is connected to a high-pressure communication pipe (58).

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

-Driving action-
Next, the operation of the air conditioner (1) will be described. Also in Embodiment 5, the air conditioner (1) can be switched between a cooling operation (see FIG. 16) and a heating operation (see FIG. 15). In addition, since it is the same as that of Embodiment 1 about air_conditionaing | cooling operation operation and heating operation operation, description is abbreviate | omitted.

(Control of suction volume ratio changing means)
Also in the fifth embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Specifically, when the operating conditions change, the controller (not shown) switches the sixth three-way valve (95) constituting the switching mechanism to the first position or the second position, and the suction volume ratio Vr is changed.

  More specifically, when the sixth three-way valve (95) is switched to the second position, the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33). It becomes a state. On the other hand, when the sixth three-way valve (95) is switched to the first position, the suction side and the discharge side of the third compression mechanism part (33) are in the same pressure state, and the refrigerant becomes the third compression mechanism part ( 33) passes through uncompressed, while the first compression mechanism (31) and the second compression mechanism (32) are in a second state where the refrigerant is compressed. In Embodiment 5, when switching to heating operation, the sixth three-way valve (95) is switched to the second position to enter the first state, and when switching to cooling operation, the sixth three-way valve (95). (95) is switched to the first position to enter the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 15, in the first state, the low-pressure gas branch pipe (25a) and the second communication pipe (27) communicate with each other.

  As a result, the low-pressure gas state refrigerant in the low-pressure gas pipe (25) is first sucked into the first compression mechanism part (31), and a part of the refrigerant is connected to the middle part of the low-pressure gas pipe (25). The gas is drawn into the third compression mechanism (33) through the gas branch pipe (25a) and the second communication pipe (27). Then, the first compression mechanism portion (31) and the third compression mechanism portion (33) are respectively compressed until they reach an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the third compression mechanism part (33) flows into the middle part of the first connection pipe (26) through the first connection joining pipe (26a). On the other hand, the refrigerant compressed to the intermediate pressure state in the first compression mechanism section (31) flows into the first communication pipe (26) and merges with the refrigerant flowing in from the first communication junction pipe (26a). The air is sucked into the second compression mechanism (32). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed downstream of the first connecting pipe (26a) of the first connecting pipe (26) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the first communication pipe (26) is sucked into the second compression mechanism section (32) after being cooled by the gas refrigerant flowing in from the injection pipe (20).

  The refrigerant sucked into the second compression mechanism section (32) is compressed in the second compression mechanism section (32) until it reaches a high pressure state. And the refrigerant | coolant compressed until it became a high pressure state in the 2nd compression mechanism part (32) is discharged by the internal space (S1) of a casing (40) via a 3rd connecting pipe (28), and is eventually discharged by high pressure. It flows into the high-pressure gas pipe (21) through the pipe (56).

  Thus, in the first state, the first compression mechanism portion (31) and the third compression mechanism portion (33) are connected in parallel and used as the low-stage compression mechanism, while the second compression mechanism portion (32). Is used as a high-stage compression mechanism. As a result, in the first state, the suction volume of the low-stage compression mechanism is the sum of the suction volume V1 of the first compression mechanism section (31) and the suction volume V3 of the third compression mechanism section (33). The suction volume of the compression mechanism is the suction volume V2 of the second compression mechanism section (32). Therefore, the suction volume ratio Vr is V2 / (V1 + V3).

  On the other hand, in the second state, the first communication branch pipe (26b) and the second communication pipe (27) are communicated with each other. As described above, the first connecting branch pipe (26b) is connected to the first connecting pipe (26), and the first connecting pipe (26) is discharged through the first connecting junction pipe (26a). Connected to tube (57). The second communication pipe (27) is connected to the third suction pipe (55). Therefore, in the second state, the suction side and the discharge side of the third compression mechanism section (33) are in communication with each other and are in an equal pressure state. Therefore, the refrigerant flows in the three compression mechanisms (31, 32, 33) are as follows.

  The refrigerant in the low-pressure state of the low-pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism part (31) is sucked into the second compression mechanism part (32) through the first communication pipe (26), and a part thereof is the first. It flows into the 3rd compression mechanism part (33) through the 1st connecting branch pipe (26b) and the 2nd connecting pipe (27) connected to the middle part of the 1 connecting pipe (26). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed upstream of the first communication branch pipe (26b) of the first communication pipe (26) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the first communication pipe (26) is cooled by the gas refrigerant flowing from the injection pipe (20), and then sucked into the second compression mechanism section (32) and the third compression mechanism section (33). ).

  The refrigerant sucked into the second compression mechanism section (32) is compressed in the second compression mechanism section (32) until it reaches a high pressure state. And the refrigerant | coolant compressed until it became a high pressure state in this 2nd compression mechanism part (32) is discharged by the internal space (S1) of a casing (40) via a 3rd connecting pipe (28), and is eventually high-pressure. It flows into the high-pressure gas pipe (21) through the discharge pipe (56).

  On the other hand, the refrigerant flowing into the third compression mechanism portion (33) passes through the inside of the third compression mechanism portion (33) without being compressed in the third compression mechanism portion (33), and is thus connected to the first communication junction pipe. It flows into the middle part of the first connecting pipe (26) through (26a).

  As described above, in the second state, the first compression mechanism (31) is used as the low-stage compression mechanism and the second compression mechanism (32) is used as the high-stage compression mechanism, while the third compression mechanism. The part (33) is not used as any compression mechanism. Thereby, in the second state, the suction volume of the low-stage compression mechanism becomes the suction volume V1 of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism becomes the suction volume of the second compression mechanism section (32). The suction volume V2. Therefore, the suction volume ratio Vr is V2 / V1.

  From the above, when the sixth three-way valve (95) constituting the switching mechanism of the suction volume ratio changing means (2) is switched from the first state to the second state, the suction volume ratio Vr increases, When the state is switched from the first state to the first state, the suction volume ratio Vr decreases.

-Effect of Embodiment 5-
As described above, also in the air conditioner (1) of the fifth embodiment, the three compression mechanism parts (31, 32, 33) are provided by the sixth three-way valve (95) constituting the switching mechanism of the suction volume ratio changing means (2). ) In the first state where the refrigerant is compressed in all the compression mechanism parts and in two compression mechanism parts (31, 32) of the three compression mechanism parts (31, 32, 33), the refrigerant is compressed. On the other hand, the suction volume ratio Vr can be easily changed by switching to the second state where the refrigerant passes through the remaining one compression mechanism section (33) without being compressed.

Embodiment 6 of the Invention
The air conditioner (1) of the sixth embodiment shown in FIGS. 17 and 18 will be described. Hereinafter, differences from the first embodiment will be described.

-Overall configuration-
In the sixth embodiment, the suction volume ratio changing means (2) includes the first state in which the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33), and the three compression mechanism portions. The refrigerant is compressed in the two compression mechanism portions (32, 33) of (31, 32, 33), while the refrigerant passes through the remaining one compression mechanism portion (31) without being compressed. A switching mechanism for switching between the two states.

  Specifically, the switching mechanism is constituted by a seventh three-way valve (96). The seventh three-way valve (96) includes first to third ports (P1, P2, P3), a first position where the first port (P1) and the second port (P2) communicate with each other, The port (P2) and the third port (P3) can be switched to a second position where they communicate.

  Also in Embodiment 6, the high-pressure discharge pipe (56) is connected to the first port (P1) of the four-way valve (17) via the high-pressure gas pipe (21). One end of the low pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17), and the other end of the low pressure gas pipe (25) is connected to the second suction pipe (53). ing. One end of the low-pressure gas branch pipe (25a) is connected to the middle part of the low-pressure gas pipe (25), and the other end of the low-pressure gas branch pipe (25a) is the third of the seventh three-way valve (96). Connected to port (P3). Furthermore, one end of the first connecting pipe (26) is connected to the second port (P2) of the seventh three-way valve (96), and the other end of the first connecting pipe (26) is connected to the first suction pipe ( 51) is connected.

  One end of a second connecting pipe (27) is connected to the second discharge pipe (54), and the other end of the second connecting pipe (27) is connected to a third suction pipe (55). One end of the second connecting / merging pipe (27a) is connected to the middle part of the second connecting pipe (27), and the other end of the second connecting / merging pipe (27a) is connected to the first discharge pipe (52). ing. In addition, one end of the second connecting branch pipe (27b) is connected to the third suction pipe (55) side of the connecting portion of the second connecting pipe (27) of the second connecting junction pipe (27a). The other end of the two connecting branch pipe (27b) is connected to the first port (P1) of the seventh three-way valve (96). Furthermore, between the connection part of the 2nd connection junction pipe (27a) of the 2nd connection pipe (27) and the connection part of the 2nd connection branch pipe (27b), one end is connected to the said gas-liquid separator (14). The other end of the connected injection pipe (20) is connected. The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

-Driving action-
Next, the operation of the air conditioner (1) will be described. Also in the sixth embodiment, the air conditioner (1) can be switched between a cooling operation (see FIG. 18) and a heating operation (see FIG. 17). In addition, since it is the same as that of Embodiment 1 about air_conditionaing | cooling operation operation and heating operation operation, description is abbreviate | omitted.

(Control of suction volume ratio changing means)
Also in the sixth embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Specifically, when the operating condition changes, the seventh three-way valve (96) constituting the switching mechanism is switched to the first position or the second position by a controller (not shown) to change the suction volume ratio Vr.

  More specifically, when the seventh three-way valve (96) is switched to the second position, the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33). It becomes a state. On the other hand, when the seventh three-way valve (96) is switched to the first position, the suction side and the discharge side of the second compression mechanism part (32) become equal to each other in the pressure state, and the refrigerant becomes the second compression mechanism part ( 32) passes through uncompressed, while the first compression mechanism (31) and the third compression mechanism (33) are in a second state where the refrigerant is compressed. Further, in the sixth embodiment, the seventh three-way valve (96) is switched to the second position when switched to the heating operation to be in the first state, and the seventh three-way valve is switched to the cooling operation. (96) is switched to the first position to enter the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 17, in the first state, the low-pressure gas branch pipe (25a) and the first communication pipe (26) communicate with each other.

  Thereby, the low-pressure gas state refrigerant in the low-pressure gas pipe (25) is sucked into the second compression mechanism part (32), and a part of the low-pressure gas is connected to the middle part of the low-pressure gas pipe (25). The air is sucked into the first compression mechanism (31) through the branch pipe (25a) and the first communication pipe (26). Then, the first compression mechanism portion (31) and the second compression mechanism portion (32) are respectively compressed until they reach an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism part (31) flows into the middle part of the second connection pipe (27) through the second connection joining pipe (27a). On the other hand, the refrigerant compressed to the intermediate pressure state in the second compression mechanism section (32) flows into the second communication pipe (27) and merges with the refrigerant flowing in from the second communication junction pipe (27a). Sucked into the third compression mechanism (33). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed downstream of the second connecting pipe (27a) of the second connecting pipe (27) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the second communication pipe (27) is cooled by the gas refrigerant flowing from the injection pipe (20) and then sucked into the third compression mechanism section (33).

  The refrigerant sucked into the third compression mechanism part (33) is compressed in the third compression mechanism part (33) until it reaches a high pressure state. And the refrigerant | coolant compressed until it became a high pressure state in the 3rd compression mechanism part (33) is discharged by the internal space (S1) of a casing (40), and a high pressure gas pipe is finally passed through a high pressure discharge pipe (56). Flows into (21).

  Thus, in the first state, the first compression mechanism portion (31) and the second compression mechanism portion (32) are connected in parallel and used as the low-stage compression mechanism, while the third compression mechanism portion (33). Is used as a high-stage compression mechanism. As a result, in the first state, the suction volume of the low-stage compression mechanism is the sum of the suction volume V1 of the first compression mechanism section (31) and the suction volume V2 of the second compression mechanism section (32). The suction volume of the compression mechanism is the suction volume V3 of the third compression mechanism section (33). Therefore, the suction volume ratio Vr is V3 / (V1 + V2).

  On the other hand, in the second state, the second connecting branch pipe (27b) and the first connecting pipe (26) are communicated. As described above, the second connecting branch pipe (27b) is connected to the second connecting pipe (27), and one end of the second connecting pipe (27) is connected to the first discharge pipe (52). The other end of the second connecting junction pipe (27a) is connected. The first communication pipe (26) is connected to the first suction pipe (51). Therefore, in the second state, the suction side and the discharge side of the first compression mechanism section (31) are in communication with each other and are in an equal pressure state. Therefore, the refrigerant flows in the three compression mechanisms (31, 32, 33) are as follows.

  The refrigerant in the low-pressure state of the low-pressure gas pipe (25) is first sucked into the second compression mechanism part (32) and compressed in the second compression mechanism part (32) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the second compression mechanism part (32) is sucked into the third compression mechanism part (33) through the second communication pipe (27), and a part thereof is the first. It flows into the 1st compression mechanism part (31) through the 2nd connecting branch pipe (27b) and the 1st connecting pipe (26) connected to the middle part of the 2 connecting pipe (27). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) passes through the injection pipe (20) upstream of the second communication branch pipe (27b) of the second communication pipe (27). Inflow. Therefore, the refrigerant flowing through the second connecting pipe (27) is cooled by the gas refrigerant flowing from the injection pipe (20), and then sucked into the third compression mechanism section (33) and the first compression mechanism section (31 ).

  The refrigerant sucked into the third compression mechanism part (33) is compressed in the third compression mechanism part (33) until it reaches a high pressure state. And the refrigerant | coolant compressed until it became a high pressure state in the 3rd compression mechanism part (33) is discharged by the internal space (S1) of a casing (40), and a high pressure gas pipe is finally passed through a high pressure discharge pipe (56). Flows into (21).

  On the other hand, the refrigerant that has flowed into the first compression mechanism section (31) passes through the inside of the first compression mechanism section (31) without being compressed in the first compression mechanism section (31), and the second communication joining pipe. It flows into the middle part of the second connecting pipe (27) through (27a).

  As described above, in the second state, the second compression mechanism (32) is used as the low-stage compression mechanism and the third compression mechanism (33) is used as the high-stage compression mechanism, while the first compression mechanism. The part (31) is not used as any compression mechanism. Thereby, in the second state, the suction volume of the low-stage compression mechanism becomes the suction volume V2 of the second compression mechanism section (32), and the suction volume of the high-stage compression mechanism becomes the suction volume of the third compression mechanism section (33). The suction volume is V3. Therefore, the suction volume ratio Vr is V3 / V2.

  As described above, when the seventh state three-way valve (96) constituting the switching mechanism of the suction volume ratio changing means (2) is switched from the first state to the second state, the suction volume ratio Vr increases, When the state is switched from the first state to the first state, the suction volume ratio Vr decreases.

-Effect of Embodiment 6-
As described above, also in the air conditioner (1) of the sixth embodiment, the three compression mechanism sections (31, 32, 33) are formed by the seventh three-way valve (96) constituting the switching mechanism of the suction volume ratio changing means (2). ) In the first state where the refrigerant is compressed in all the compression mechanism parts and in two compression mechanism parts (32, 33) of the three compression mechanism parts (31, 32, 33). On the other hand, the suction volume ratio Vr can be easily changed by switching to the second state in which the refrigerant passes through the remaining one compression mechanism (31) without being compressed.

<< Embodiment 7 of the Invention >>
The air conditioner (1) of the seventh embodiment shown in FIGS. 19 and 20 will be described. Hereinafter, differences from the first embodiment will be described.

-Overall configuration-
In the seventh embodiment, the suction volume ratio changing means (2) includes the first state in which the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33), and the three compression mechanism portions. The refrigerant is compressed in the two compression mechanism portions (31, 33) of (31, 32, 33), while the refrigerant passes through the remaining one compression mechanism portion (32) without being compressed. A switching mechanism for switching between the two states.

  Specifically, the switching mechanism includes an eighth three-way valve (97) and a ninth three-way valve (98). The eighth three-way valve (97) and the ninth three-way valve (98) have first to third ports (P1, P2, P3), respectively, and the first port (P1) and the second port (P2) communicate with each other. And a second position where the second port (P2) and the third port (P3) communicate with each other.

  Also in Embodiment 7, the high-pressure discharge pipe (56) is connected to the first port (P1) of the four-way valve (17) through the high-pressure gas pipe (21). One end of the low pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17). The other end of the low pressure gas pipe (25) is connected to the first suction pipe (51).

  One end of the first connecting pipe (26) is connected to the first discharge pipe (52), and the other end of the first connecting pipe (26) is connected to the second suction pipe (53). One end of the first connecting / merging pipe (26a) is connected to the middle part of the first connecting pipe (26), and the other end of the first connecting / merging pipe (26a) is connected to the eighth three-way valve (97). Connected to the first port (P1). In addition, one end of the first connection branch pipe (26b) is connected to the second suction pipe (53) side of the connection part of the first connection junction pipe (26a) in the middle of the first connection pipe (26). The other end of the first connecting branch pipe (26b) is connected to the first port (P1) of the ninth three-way valve (98). Furthermore, between the connection part of the 1st connection junction pipe (26a) of the 1st connection pipe (26) and the connection part of the 1st connection branch pipe (26b), one end is said gas-liquid separator (14). The other end of the connected injection pipe (20) is connected. The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  One end of a second connecting pipe (27) is connected to the second discharge pipe (54), and the other end of the second connecting pipe (27) is connected to the second port (P2 of the eighth three-way valve (97). )It is connected to the. One end of a third connecting pipe (28) is connected to the third port (P3) of the eighth three-way valve (97), and the other end of the third connecting pipe (28) is the ninth three-way valve (98). Connected to the third port (P3). The second port (P2) of the ninth three-way valve (98) is connected to one end of the fourth connecting pipe (29), and the other end of the fourth connecting pipe (29) is connected to the third suction pipe (55). It is connected to the.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

-Driving action-
Next, the operation of the air conditioner (1) will be described. In the seventh embodiment, the air conditioner (1) can be switched between a cooling operation (see FIG. 19) and a heating operation (see FIG. 20). In addition, since it is the same as that of Embodiment 1 about air_conditionaing | cooling operation operation and heating operation operation, description is abbreviate | omitted.

(Control of suction volume ratio changing means)
Also in the seventh embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Specifically, when the operating condition changes, the controller (not shown) switches the eighth three-way valve (97) and the ninth three-way valve (98) constituting the switching mechanism to the first position or the second position, and the suction is performed. The volume ratio Vr is changed.

  More specifically, when the eighth three-way valve (97) and the ninth three-way valve (98) are switched to the second position, in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33). It will be in the 1st state where a refrigerant is compressed. On the other hand, when the eighth three-way valve (97) and the ninth three-way valve (98) are switched to the first position, the suction side and the discharge side of the second compression mechanism section (32) are in an equal pressure state and the refrigerant Passes through the second compression mechanism section (32) without compression, while the first compression mechanism section (31) and the third compression mechanism section (33) are in the second state in which the refrigerant is compressed. In the seventh embodiment, when switching to the cooling operation, the eighth three-way valve (97) and the ninth three-way valve (98) are switched to the second position to be in the first state and switched to the heating operation. At that time, the eighth three-way valve (97) and the ninth three-way valve (98) are switched to the first position to be in the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 19, in the first state, the second connecting pipe (27) and the third connecting pipe (28) are communicated with each other, and the third connecting pipe (28) and the fourth connecting pipe (29 ).

  As a result, the refrigerant in the low pressure state of the low pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism section (31) is sucked into the second compression mechanism section (32) through the first communication pipe (26). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) flows into the middle part of the first communication pipe (26) through the injection pipe (20). Therefore, the refrigerant flowing through the first communication pipe (26) is sucked into the second compression mechanism section (32) after being cooled by the gas refrigerant flowing in from the injection pipe (20).

  The refrigerant sucked into the second compression mechanism part (32) is compressed in the second compression mechanism part (32). And the refrigerant | coolant compressed in the 2nd compression mechanism part (32) passes a 2nd connection pipe (27), a 3rd connection pipe (28), and a 4th connection pipe (29), and becomes a 3rd compression mechanism part (33). ) And compressed in the third compression mechanism (33) until a high pressure state is reached.

  The refrigerant compressed to the high pressure state in the third compression mechanism section (33) is discharged into the internal space (S1) of the casing (40), and eventually the high pressure gas pipe (21 through the high pressure discharge pipe (56). ).

  Thus, in the first state, the first compression mechanism (31) is used as the low-stage compression mechanism, while the second compression mechanism (32) and the third compression mechanism (33) are connected in series. Used as a high-stage compression mechanism. Thus, in the first state, the suction volume of the low-stage compression mechanism is the suction volume V1 of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism is the upstream second compression mechanism section ( 32). Therefore, the suction volume ratio Vr is V2 / V1.

 On the other hand, in the second state, the second connecting pipe (27) and the first connecting junction pipe (26a) are communicated with each other, and the first connecting branch pipe (26b) and the fourth connecting pipe (29) are connected. Communicated. As described above, the first connecting pipe (26) is connected to the second suction pipe (53), and the first connecting branch pipe (26b) is connected to the first connecting pipe (26). The first communication pipe (26) is connected to the first communication junction pipe (26a) communicating with the second discharge pipe (54) through the second communication pipe (27). Therefore, in the second state, the suction side and the discharge side of the second compression mechanism section (32) are in communication with each other and are in an equal pressure state. Therefore, the refrigerant flows in the three compression mechanisms (31, 32, 33) are as follows.

  The refrigerant in the low-pressure state of the low-pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism part (31) flows into the second compression mechanism part (32) through the first connecting pipe (26), and a part thereof is the first. The air is sucked into the third compression mechanism (33) through the first connecting branch pipe (26b) and the fourth connecting pipe (29) connected to the middle part of the connecting pipe (26). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) is disposed upstream of the first communication branch pipe (26b) of the first communication pipe (26) via the injection pipe (20). Inflow. Therefore, the refrigerant flowing through the first communication pipe (26) is cooled by the gas refrigerant flowing from the injection pipe (20), and then flows into the second compression mechanism section (32) and the third compression mechanism section (33). Inhaled.

  The refrigerant flowing into the second compression mechanism part (32) passes through the inside of the second compression mechanism part (32) without being compressed in the second compression mechanism part (32), and the second communication pipe (27). And it flows into the middle part of the 1st connecting pipe (26) through the 1st connecting pipe (26a).

  On the other hand, the refrigerant sucked into the third compression mechanism part (33) is compressed in the third compression mechanism part (33) until it reaches a high pressure state. And the refrigerant | coolant compressed until it became a high pressure state in the 3rd compression mechanism part (33) is discharged by the internal space (S1) of a casing (40), and a high pressure gas pipe is finally passed through a high pressure discharge pipe (56). Flows into (21).

  Thus, in the second state, the first compression mechanism (31) is used as the low-stage compression mechanism and the third compression mechanism (33) is used as the high-stage compression mechanism, while the second compression mechanism. The part (32) is not used as any compression mechanism. Thus, in the second state, the suction volume of the low-stage compression mechanism becomes the suction volume V1 of the first compression mechanism part (31), and the suction volume of the high-stage compression mechanism becomes the suction volume of the third compression mechanism part (33). The suction volume is V3. Therefore, the suction volume ratio Vr is V3 / V1.

  From the above, when the eighth three-way valve (97) and the ninth three-way valve (98) constituting the switching mechanism of the suction volume ratio changing means (2) are switched from the first state to the second state, the suction volume ratio While Vr decreases, the suction volume ratio Vr increases when the second state is switched to the first state.

-Effect of Embodiment 7-
As described above, the air compression apparatus (1) of the seventh embodiment also performs the three compressions by the eighth three-way valve (97) and the ninth three-way valve (98) that constitute the switching mechanism of the suction volume ratio changing means (2). A first state in which the refrigerant is compressed in all the compression mechanism parts of the mechanism parts (31, 32, 33), and two compression mechanism parts (31, 31) of the three compression mechanism parts (31, 32, 33) In 33), the suction volume ratio Vr is easily changed by switching to the second state in which the refrigerant is compressed while the refrigerant is compressed in the remaining one compression mechanism (32). Can do.

<< Embodiment 8 of the Invention >>
The air conditioner (1) of Embodiment 8 shown in FIGS. 21 and 22 will be described. Hereinafter, differences from the first embodiment will be described.

-Overall configuration-
In the eighth embodiment, the suction volume ratio changing means (2) has a switching mechanism for changing the position of the intermediate stage of the compressor (11). The switching mechanism is configured to be able to change the connection destination of the injection pipe (20) constituting the cooling means for cooling the refrigerant between the low-stage side compression mechanism and the high-stage side compression mechanism.

  Specifically, the switching mechanism is constituted by a tenth three-way valve (99). The tenth three-way valve (99) includes first to third ports (P1, P2, P3), a first position where the first port (P1) and the second port (P2) communicate with each other, The port (P2) and the third port (P3) can be switched to a second position where they communicate.

  Also in the eighth embodiment, the high-pressure discharge pipe (56) is connected to the first port (P1) of the four-way valve (17) through the high-pressure gas pipe (21). One end of the low pressure gas pipe (25) is connected to the third port (P3) of the four-way valve (17). The other end of the low pressure gas pipe (25) is connected to the first suction pipe (51).

  One end of the first connecting pipe (26) is connected to the first discharge pipe (52), and the other end of the first connecting pipe (26) is connected to the second suction pipe (53). Further, one end of the second communication pipe (27) is connected to the second discharge pipe (54), and the other end of the second communication pipe (27) is connected to the third suction pipe (55). .

  In the eighth embodiment, the other end of the injection pipe (20) having one end connected to the gas-liquid separator (14) is connected to the second port (P2) of the tenth three-way valve (99). One end of the first injection pipe (28) is connected to the first port (P1) of the tenth three-way valve (99), and the other end of the first injection pipe (28) is connected to the first communication pipe (26 ) Is connected to the middle part. Further, one end of the second injection pipe (29) is connected to the third port (P3) of the tenth three-way valve (99), and the other end of the second injection pipe (29) is connected to the second communication pipe (27 ) Is connected to the middle part.

  The injection pipe (20) cools the refrigerant being compressed by joining the gas refrigerant separated by the gas-liquid separator (14) with the refrigerant being compressed in the compressor (11). The cooling means is configured.

  Since other configurations are the same as those of the first embodiment, description thereof is omitted.

-Driving action-
Next, the operation of the air conditioner (1) will be described. Also in the eighth embodiment, the air conditioner (1) can be switched between a cooling operation (see FIG. 21) and a heating operation (see FIG. 22). In addition, since it is the same as that of Embodiment 1 about air_conditionaing | cooling operation operation and heating operation operation, description is abbreviate | omitted.

(Control of suction volume ratio changing means)
Also in the eighth embodiment, when the operating condition of the air conditioner (1) changes, the suction volume ratio Vr is changed by the suction volume ratio changing means (2). Specifically, when the operating conditions change, the controller (not shown) switches the tenth three-way valve (99) constituting the switching mechanism to the first position or the second position, thereby changing the suction volume ratio Vr.

  More specifically, when the tenth three-way valve (99) is switched to the first position, the injection pipe (20) constituting the cooling means is connected to the first compression mechanism part (31) and the second compression mechanism part (32). ) Is connected to the first state. On the other hand, when the tenth three-way valve (99) is switched to the second position, the injection pipe (20) constituting the cooling means is located between the second compression mechanism part (32) and the third compression mechanism part (33). It will be in the 2nd state connected to. In the eighth embodiment, the tenth three-way valve (99) is switched to the first position when switched to the cooling operation to be in the first state, and the tenth three-way valve is switched to the heating operation. (99) is switched to the second position to enter the second state. Hereinafter, the relationship between each state and the suction volume ratio Vr will be described in detail.

  As shown in FIG. 21, in the first state, the injection pipe (20) communicates with the first injection pipe (28). Since the 1st injection pipe (28) is connected to the middle part of the 1st connecting pipe (26) which connects the 1st compression mechanism part (31) and the 2nd compression mechanism part (32), it is the 1st In the state, the injection pipe (20) is connected between the first compression mechanism part (31) and the second compression mechanism part (32) via the first injection pipe (28). Therefore, the refrigerant flows in the three compression mechanisms (31, 32, 33) are as follows.

  The refrigerant in the low-pressure state of the low-pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed in the first compression mechanism (31) until it reaches an intermediate pressure state.

  The refrigerant compressed to the intermediate pressure state in the first compression mechanism section (31) is sucked into the second compression mechanism section (32) through the first communication pipe (26). The gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) flows into the middle part of the first communication pipe (26) through the injection pipe (20) and the first injection pipe (28). . Therefore, the refrigerant flowing through the first communication pipe (26) is sucked into the second compression mechanism section (32) after being cooled by the gas refrigerant flowing in from the injection pipe (20).

  The refrigerant sucked into the second compression mechanism part (32) is compressed in the second compression mechanism part (32), and sucked into the third compression mechanism part (33) through the second connecting pipe (27). . The refrigerant sucked into the third compression mechanism part (33) is compressed in the third compression mechanism part (33) until it reaches a high pressure state.

  The refrigerant compressed to the high pressure state in the third compression mechanism section (33) is discharged into the internal space (S1) of the casing (40), and eventually the high pressure gas pipe (21 through the high pressure discharge pipe (56). ).

  Thus, in the first state, the refrigerant between the first compression mechanism part (31) and the second compression mechanism part (32) is cooled by the gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14). Is done. Thereby, while the 1st compression mechanism part (31) is used as a low stage compression mechanism, the 2nd compression mechanism part (32) and the 3rd compression mechanism part (33) are connected in series, and a high stage compression mechanism Will be used. As a result, in the first state, the suction volume of the low-stage compression mechanism is the suction volume V1 of the first compression mechanism section (31), and the suction volume of the high-stage compression mechanism is the upstream second compression mechanism section ( 32). Therefore, the suction volume ratio Vr is V2 / V1.

 On the other hand, in the second state, the injection pipe (20) communicates with the second injection pipe (29). Since the 2nd injection pipe (29) is connected to the middle part of the 2nd connecting pipe (27) which connects the 2nd compression mechanism part (32) and the 3rd compression mechanism part (33), it is 2nd In the state, the injection pipe (20) is connected between the second compression mechanism part (32) and the third compression mechanism part (33) via the second injection pipe (29). Therefore, the refrigerant flows in the three compression mechanisms (31, 32, 33) are as follows.

  The refrigerant in the low pressure state of the low pressure gas pipe (25) is first sucked into the first compression mechanism (31) and compressed. Then, the refrigerant compressed in the first compression mechanism part (31) is sucked into the second compression mechanism part (32) through the first connecting pipe (26), and is intermediated in the second compression mechanism part (32). Compressed until pressure is reached.

  The refrigerant compressed to the intermediate pressure state in the second compression mechanism section (32) is sucked into the third compression mechanism section (33) through the second communication pipe (27), and the third compression mechanism section ( In 33), it is compressed until it reaches a high pressure state. In addition, the gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14) flows into the middle part of the second communication pipe (27) through the injection pipe (20) and the second injection pipe (29). . Therefore, the refrigerant flowing through the second communication pipe (27) is cooled by the gas refrigerant flowing from the injection pipe (20) and then sucked into the third compression mechanism section (33).

  The refrigerant compressed to the high pressure state in the third compression mechanism section (33) is discharged into the internal space (S1) of the casing (40), and eventually the high pressure gas pipe (21 through the high pressure discharge pipe (56). ).

  Thus, in the second state, the refrigerant between the second compression mechanism part (32) and the third compression mechanism part (33) is cooled by the gas refrigerant separated from the liquid refrigerant in the gas-liquid separator (14). Is done. As a result, the first compression mechanism section (31) and the second compression mechanism section (32) are connected in series and used as a low-stage compression mechanism, while the third compression mechanism section (33) is used as a high-stage compression mechanism. Used as As a result, in the first state, the suction volume of the low-stage compression mechanism is the suction volume V1 of the upstream first compression mechanism section (31), and the suction volume of the high-stage compression mechanism is the third compression mechanism section ( 33). Therefore, the suction volume ratio Vr is V3 / V1.

  As described above, when the tenth three-way valve (99) constituting the switching mechanism of the suction volume ratio changing means (2) is switched from the first state to the second state, the suction volume ratio Vr is decreased while the second volume When the state is switched from the first state to the first state, the suction volume ratio Vr increases.

-Effect of Embodiment 8-
As described above, also in the air conditioner (1) of the eighth embodiment, the position of the intermediate stage of the compressor (11) is changed by the tenth three-way valve (99) constituting the switching mechanism of the suction volume ratio changing means (2). By changing, the suction volume ratio Vr can be easily changed.

  In the eighth embodiment, the first compression mechanism section (31) constitutes the first compression mechanism section according to the present invention, and the second compression mechanism section (32) is the second compression mechanism section according to the present invention. The third compression mechanism part (33) constitutes the third compression mechanism part according to the present invention. However, the configurations of the first compression mechanism unit, the second compression mechanism unit, and the third compression mechanism unit according to the present invention are not limited to this, and for example, the second compression mechanism unit (32) is the first compression mechanism unit according to the present invention. 1 compression mechanism part, the 1st compression mechanism part (31) constitutes the 2nd compression mechanism part concerning the present invention, and the 3rd compression mechanism part (33) concerning the 3rd compression mechanism part concerning the present invention (33) may be configured.

<< Other Embodiments >>
About each embodiment mentioned above, it is good also as following structures.

  For example, you may comprise the said compression mechanism like the modification shown in FIG.

  In this modification, the two-cylinder chamber type compression mechanism unit is configured as two compression mechanism units in which two cylinder chambers are independent from each other, and the compressor includes one two-cylinder chamber type compression mechanism unit and one one-cylinder chamber type. A compression mechanism is provided.

  Specifically, as shown in FIG. 23, the compressor (11) includes an electric motor (34) and a compression mechanism (31, 32, 33) in a vertically long and sealed casing (21). It is stored. Since this compressor (11) has basically the same configuration as that of the first embodiment except for the compression mechanism (31, 32, 33), only the differences from the first embodiment will be described below.

  In the compressor (11), a two-cylinder chamber type compression mechanism (31, 32) is disposed below, and a one-cylinder chamber type compression mechanism (33) is disposed above. The first compression mechanism portion (31) and the second compression mechanism portion (32) are configured by the two-cylinder chamber type compression mechanism portion (31, 32), and the first cylinder chamber-type compression mechanism portion (33) is the first. 3 compression mechanism part (33) is comprised.

  That is, the first compression mechanism portion is formed by the inner cylinder chamber (C2) formed between the cylinder (61 (71)) and the piston (62 (72)) of the two-cylinder chamber type compression mechanism portion (31, 32). (31) is configured, and the second compression mechanism (32) is configured by the outer cylinder chamber (C1). A first suction pipe (51) and a first discharge pipe (52) communicate with the first compression mechanism section (31), and a second suction pipe (53) and a second discharge pipe communicate with the second compression mechanism section (32). The pipe (54) is in communication.

  A middle plate (38) is provided between the two-cylinder chamber type compression mechanism (31, 32) and the one-cylinder chamber type compression mechanism (33). The cylinder (81) and the piston (80) of the third compression mechanism (33) are disposed between the middle plate (38) and the front head (37).

  The drive shaft (35) includes an eccentric portion (35b (35c)) that fits with the annular piston (62 (72)) of the first and second compression mechanism portions (31, 32), and a third compression mechanism. An eccentric portion (35d) that fits with the eccentric piston (82) of the portion (33) is formed.

  The axial length of the two-cylinder chamber type compression mechanism (31, 32) is set larger than the axial length of the one-cylinder chamber type compression mechanism (33) because of the cylinder volume.

  Even if the compression mechanism (31, 32, 33) is configured in this way, it can be connected to the refrigerant circuit (10) of the first to eighth embodiments. In the same manner as in the first to eighth embodiments, it is possible to change the suction volume ratio and perform the optimum COP operation by switching between two operation states.

  In each of the above embodiments, the refrigerant charged in the refrigerant circuit (10) may be a refrigerant other than carbon dioxide (for example, a fluorocarbon refrigerant).

  In each of the above embodiments, the three compression mechanisms (31, 32, 33) are so-called oscillating pistons in which the blades (63, 73, 83) are integrally formed with the pistons (62, 72, 82). The three compression mechanisms (31, 32, 33) were formed separately from the pistons (62, 72, 82) with the blades (63, 73, 83). It may be constituted by a so-called rolling piston type compression mechanism.

  In each of the above embodiments, the injection pipe (20) is used as a cooling means for cooling the refrigerant in the intermediate stage of the compressor (11). However, a heat exchanger (intercooler) may be used as the cooling means. Good.

  In each of the above embodiments, a three-way valve or a four-way valve is used as the switching mechanism of the suction volume ratio changing means (2). However, the switching mechanism can be replaced by a plurality of electromagnetic valves.

  In each of the above embodiments, the suction volume ratio Vr is changed by the suction volume ratio changing means (2) when switching to the cooling operation or the heating operation. Needless to say, a high COP can be obtained regardless of changes in operating conditions by changing the operating conditions according to changes in various operating conditions.

  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 for a two-stage compression refrigeration cycle.

1 is a refrigerant circuit diagram of an air-conditioning apparatus according to Embodiment 1. FIG. FIG. 2 is a longitudinal sectional view of the compressor according to the first embodiment. FIG. 3 is a cross-sectional view of the first and third compression mechanism portions of the first embodiment. FIG. 4 is an operation state diagram of the first and third compression mechanisms of the first embodiment. FIG. 5 is a cross-sectional view of the second compression mechanism unit of the first embodiment. FIG. 6 is an operation state diagram of the second compression mechanism unit of the first embodiment. FIG. 7 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 1. FIG. 8 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 1. FIG. 9 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 2. FIG. 10 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 2. FIG. 11 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 3. FIG. 12 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 3. FIG. 13 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 4. FIG. 14 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 4. FIG. 15 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 5. FIG. 16 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 5. FIG. 17 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 6. FIG. 18 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 6. FIG. 19 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 7. FIG. 20 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 7. FIG. 21 is a refrigerant circuit diagram illustrating a refrigerant flow in the first state of the air-conditioning apparatus according to Embodiment 8. FIG. 22 is a refrigerant circuit diagram illustrating a refrigerant flow in the second state of the air-conditioning apparatus according to Embodiment 8. FIG. 23 is a longitudinal sectional view of a compressor according to a modification.

Explanation of symbols

1 Air conditioning equipment (refrigeration equipment)
2 Inhalation volume ratio change means
10 Refrigerant circuit
11 Compressor
18 First three-way valve (switching mechanism)
19 Second three-way valve (switching mechanism)
31 1st compression mechanism part
32 Second compression mechanism
33 Third compression mechanism
35 Drive shaft
90 3rd three-way valve (switching mechanism)
91 Fourth three-way valve (switching mechanism)
92 Second four-way valve (switching mechanism)
93 Third four-way valve (switching mechanism)
94 Fifth three-way valve (switching mechanism)
95 Sixth three-way valve (switching mechanism)
96 Seventh three-way valve (switching mechanism)
97 Eighth three-way valve (switching mechanism)
98 Ninth three-way valve (switching mechanism)
99 10th three way valve (switching mechanism)

Claims (13)

A two-stage compression refrigeration comprising a refrigerant circuit (10) having a compressor (11) in which a plurality of rotary type compression mechanisms (31, 32, 33) are mechanically connected by a single drive shaft (35) A refrigeration apparatus for performing a cycle,
The compressor (11) includes three compression mechanism portions (31, 32, 33),
The at least one compression mechanism portion is a two-cylinder chamber type compression mechanism portion (having two cylinder chambers on the inner peripheral side and the outer peripheral side of an annular eccentric piston (62, 82) that performs eccentric rotational movement in the cylinder space ( 31, 33),
The other compression mechanism is composed of a one-cylinder chamber type compression mechanism (32) having one cylinder chamber on the outer peripheral side of an eccentric piston (72) that performs eccentric rotational movement in the cylinder space,
A refrigeration apparatus comprising suction volume ratio changing means (2) for changing a suction volume ratio, which is a ratio of a suction volume between a low stage side compression mechanism and a high stage side compression mechanism. In claim 1,
The two-cylinder chamber type compression mechanism is configured as one compression mechanism having two cylinder chambers,
A refrigeration apparatus comprising two two-cylinder chamber compression mechanisms and one one-cylinder chamber compression mechanism. In claim 1,
The two-cylinder chamber type compression mechanism section is configured as two compression mechanism sections in which the two cylinder chambers are independent of each other.
One refrigeration apparatus provided with one two-cylinder chamber type compression mechanism and one one-cylinder chamber type compression mechanism. In any one of Claims 1-3,
The refrigeration apparatus, wherein the suction volume ratio changing means (2) changes the suction volume ratio by changing a connection relation of the three compression mechanisms (31, 32, 33). In claim 4,
The suction volume ratio changing means (2) includes two compression mechanism portions (31, 32) used as a low-stage compression mechanism among the three compression mechanism portions (31, 32, 33) connected in series. And a switching mechanism (18, 19) for switching between the connected state and the state connected in parallel. In claim 4,
The suction volume ratio changing means (2) includes two compression mechanism portions (32, 33) used as high-stage compression mechanisms among the three compression mechanism portions (31, 32, 33) connected in series. And a switching mechanism (90, 91) for switching between a connected state and a state connected in parallel. In claim 4,
Any two compression mechanism portions (31, 32) of the three compression mechanism portions (31, 32, 33) are configured to have different suction volumes,
The suction volume ratio changing means (2) has a switching mechanism (92, 93) for changing the connection relationship between the two compression mechanisms (31, 32) having different suction volumes. apparatus. In claim 7,
One of the two compression mechanisms (31, 32) is used as a low-stage compression mechanism, and the other is used as a high-stage compression mechanism. In any one of Claims 1-3,
The suction volume ratio changing means (2)
A first state in which the refrigerant is compressed in all the compression mechanism portions of the three compression mechanism portions (31, 32, 33);
While the refrigerant is compressed in two of the three compression mechanism parts (31, 32, 33), the suction side and the discharge side are in the same pressure state in the remaining one compression mechanism part. And a switching mechanism (94, 95, 96, 97, 98) for switching to a second state in which the refrigerant passes without being compressed. In claim 9,
The switching mechanism (94, 95, 96)
In the first state, any two compression mechanism portions of the three compression mechanism portions (31, 32, 33) are connected in parallel,
In the second state, the suction side and the discharge side of one compression mechanism part of the two compression mechanism parts connected in parallel in the first state are configured to communicate with each other. Refrigeration equipment. In claim 9,
Any two compression mechanism portions (32, 33) of the three compression mechanism portions (31, 32, 33) are configured to have different suction volumes,
The switching mechanism (97, 98)
In the first state, the two compression mechanism portions (32, 33) having different suction volumes are connected in series, and both compression mechanism portions (32, 33) serve as a low-stage compression mechanism or a high-stage compression mechanism. While used
In the second state, the suction side and the discharge side of the upstream compression mechanism portion (32) of the two compression mechanism portions (32, 33) connected in series in the first state are communicated with each other. A refrigeration apparatus configured to be configured as described above. In claim 1,
The three compression mechanism sections (31, 32, 33) are connected in series in the order of the first compression mechanism section (31), the second compression mechanism section (32), and the third compression mechanism section (33). ,
The suction volume ratio changing means (2)
While cooling the refrigerant between the first compression mechanism part (31) and the second compression mechanism part (32) to use the first compression mechanism part (31) as a low-stage compression mechanism, A first state in which the second compression mechanism (32) and the third compression mechanism (33) are used as a high-stage compression mechanism;
The refrigerant between the second compression mechanism part (32) and the third compression mechanism part (33) is cooled to thereby provide the first compression mechanism part (31) and the second compression mechanism part (32). And a switching mechanism (98) for switching to a second state in which the third compression mechanism (33) is used as a high-stage compression mechanism. Refrigeration equipment. In any one of claims 1 to 12,
A refrigerating apparatus, wherein the refrigerant flowing through the refrigerant circuit (10) is carbon dioxide.

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