JP2018009565A - Multi-stage compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-stage compressor which can suitably perform injection irrespective of an operation condition.SOLUTION: A multi-stage compressor 2 comprises: a hermetic housing 3; and at least two or more stages of compression mechanisms accommodated within the hermetic housing 3, the at least two or more stages of compression mechanisms including a low-stage side compression mechanism 4 into which a refrigerant is sucked from a refrigeration cycle 1, 1A, and also including a high-stage side compression mechanism 6 which sucks in a refrigerant compressed by the low-stage side compression mechanism 4 and compresses the refrigerant. In the multi-stage compressor 2, a refrigerant extracted from the refrigeration cycle is injected into the low-stage side compression mechanism 4.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a multi-stage compressor.

  Conventionally, multistage compressors are known as measures for improving compressor efficiency and refrigeration cycle efficiency (COP). As such a multistage compressor, a compressor having a high-stage compression mechanism and a low-stage compression mechanism housed in a housing and driving a plurality of compression mechanisms by a single drive shaft has been proposed ( For example, see Patent Document 1 below). In this configuration, the inside of the sealed housing is set to an intermediate pressure by discharging the refrigerant compressed by the low-stage compression mechanism into the sealed housing. And, by injecting the intermediate pressure refrigerant extracted from the refrigerant circuit into the sealed housing container that becomes intermediate pressure, and by injecting oil and refrigerant having a pressure higher than the intermediate pressure refrigerant into the high-stage compression mechanism, It is possible to reduce the size of the compressor, further improve the COP, and ensure reliability.

Japanese Patent No. 4949817

  However, in the configuration in which the lower stage side and the higher stage side have the same rotational speed as described in Patent Document 1, the intermediate pressure (equal to the suction pressure on the higher stage side) is caused by the volume ratio between the lower stage side and the higher stage side. Because of the configuration in which refrigerant is injected into the high-stage compression mechanism, there may be cases where the operation amount is low or cannot be injected in low compression ratio operation, and the targeted efficiency improvement effect may not be obtained. .

  An object of this indication is to provide the multistage compressor which can implement injection suitably irrespective of an operating state, and can improve efficiency.

  The multistage compressor (2, 2A, 2B, 2C, 2D, 2E, 2F, 2G) according to the present disclosure is accommodated in the hermetic housing (3) and the hermetic housing, and refrigerant is supplied from the refrigeration cycle (1, 1A). A plurality of compression mechanisms of at least two stages including a low-stage compression mechanism (4) to be sucked and a high-stage compression mechanism (6) that sucks and compresses the refrigerant compressed by the low-stage compression mechanism; . In this multistage compressor, the refrigerant extracted from the refrigeration cycle is injected into the low-stage compression mechanism.

  With this configuration, the low-stage compression mechanism that first compresses the refrigerant sucked from the refrigeration cycle among the plurality of compression mechanisms, that is, the compression mechanism having the smallest pressure in the compression chamber, is injected, so in the low compression ratio operation Also, the injection can be performed satisfactorily.

  ADVANTAGE OF THE INVENTION According to this invention, injection can be implemented suitably irrespective of a driving | running state, and the multistage compressor which can improve efficiency can be provided.

FIG. 1 is a diagram illustrating a configuration of a refrigeration cycle in which a multistage compressor according to a first embodiment is provided. FIG. 2 is a diagram showing a schematic configuration of the multistage compressor shown in FIG. FIG. 3 is a longitudinal sectional view of the multistage compressor shown in FIG. FIG. 4 is a diagram illustrating shapes of a fixed scroll and a movable scroll included in the multistage compressor, and is a diagram illustrating a cross section taken along the line IV-IV in FIG. 3. FIG. 5 is a diagram illustrating a schematic configuration of a multistage compressor according to a modification of the first embodiment. FIG. 6 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 7 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 8 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 9 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 10 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 11 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 12 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 13 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 14 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 15 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 16 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 17 is a diagram illustrating a schematic configuration of a multistage compressor according to another modification of the first embodiment. FIG. 18 is a longitudinal sectional view of a multistage compressor according to the second embodiment. FIG. 19 is a view showing a cross section XIX-XIX in FIG. FIG. 20 is a view showing a XX-XX cross section of FIG. FIG. 21 is a longitudinal sectional view of a multistage compressor according to the third embodiment. FIG. 22 is a longitudinal sectional view of a multistage compressor according to the fourth embodiment. FIG. 23 is a view showing a XXIII-XXIII cross section of FIG. FIG. 24 is a view showing a XXIV-XXIV cross section of FIG. FIG. 25 is a diagram showing the internal structure of the multistage compressor shown in FIG. FIG. 26 is a view showing a XXVI-XXVI cross section of FIG. FIG. 27 is a diagram illustrating a modification of the multistage compressor according to the fourth embodiment. FIG. 28 is a longitudinal sectional view of a multistage compressor according to the fifth embodiment. FIG. 29 is a view showing a XXIX-XXIX cross section of FIG. FIG. 30 is a longitudinal sectional view of a multistage compressor according to the sixth embodiment. FIG. 31 is a view showing a XXXI-XXXI cross section of FIG. 30. FIG. 32 is a longitudinal sectional view of a multistage compressor according to the seventh embodiment. 33 is a diagram showing a cross section of XXXIII-XXXIII in FIG. 32. FIG. 34 is a diagram showing an internal structure of the multistage compressor shown in FIG. FIG. 35 is a longitudinal sectional view of a multistage compressor according to the eighth embodiment. 36 is a view showing a XXXVI-XXXVI cross section of FIG. FIG. 37 is a diagram showing another configuration of the refrigeration cycle.

  Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  The first embodiment will be described with reference to FIGS. First, the configuration of the refrigeration cycle 1 provided with the multistage compressor 2 according to the first embodiment will be described with reference to FIGS. In FIG. 1, each component of the refrigeration cycle 1 is illustrated on the ph diagram based on the pressure p of the refrigerant passing through each component of the refrigeration cycle 1 and the enthalpy h. The vertical axis in FIG. 1 represents the refrigerant pressure p, and the horizontal axis in FIG. 1 represents the enthalpy h of the refrigerant.

  As shown in FIGS. 1 and 2, the refrigeration cycle 1 includes a multi-stage compressor 2 in which two compression mechanisms, a low-stage compression mechanism 4 and a high-stage compression mechanism 6, are housed and installed in one sealed housing 3. Have. The multistage compressor 2 has a sealed intermediate pressure chamber 5 in which a low-stage compression mechanism 4 and a high-stage compression mechanism 6 are connected. The intermediate pressure chamber 5 forms a space separated from the internal suction pressure space in which the low-stage compression mechanism 4 and the high-stage compression mechanism 6 are accommodated in the sealed housing 3. In the intermediate pressure chamber 5, the intermediate pressure refrigerant compressed and discharged by the low-stage compression mechanism 4 passes (a throttle may be provided in the passage and a muffler function may be added) and introduced into the high-stage compression mechanism 6. The The detailed configuration of the multistage compressor 2 will be described later.

  The operation (operation) during the cooling operation of the refrigeration cycle 1 will be described below. A discharge pipe 7 is connected to the high-stage compression mechanism 6 of the multistage compressor 2, and the other end of the discharge pipe 7 is connected to a radiator 8 as shown in FIG. 1. In the radiator 8, the high-temperature and high-pressure refrigerant is cooled by exchanging heat with water in the case of a water heater and with air in the case of an air conditioner.

  A first regulating valve 26 and a first gas-liquid separator 9 are provided downstream of the radiator 8, and after cooling and depressurizing by the radiator 8, the refrigerant decompressed by the first regulating valve 26 is gas-liquid separated. ing. A second regulating valve 24 and a second gas / liquid separator 10 are provided downstream of the first gas / liquid separator 9, and the pressure is reduced by the second regulating valve 24 after being output from the first gas / liquid separator 9 and decompressed. The separated refrigerant is gas-liquid separated. A third regulating valve 22 and a third gas / liquid separator 11 are provided downstream of the second gas / liquid separator 10, and the pressure is reduced by the third regulating valve 22 after being output from the second gas / liquid separator 10 and decompressed. The separated refrigerant is gas-liquid separated.

  A pressure reducing valve 12 is provided downstream of the third gas-liquid separator 11. The low-temperature and low-pressure gas-liquid two-phase refrigerant decompressed through the pressure reducing valve 12 is heat-exchanged with the air blown by an evaporator fan (not shown) in the evaporator 13, and absorbs heat from the air to be vaporized. ing. Further, the refrigerant evaporated in the evaporator 13 is configured to be sucked into the low-stage compression mechanism 4 of the multistage compressor 2 through the suction pipe 14 connected between the evaporator 13 and the multistage compressor 2. Yes.

  As shown in FIGS. 1 and 2, the low-stage compression mechanism 4 of the multistage compressor 2 includes a third injection pipe 21 for injecting refrigerant into the low-stage compression mechanism 4. 11, the pressure of the third regulating valve 22 is reduced to a desired pressure, and the refrigerant is separated into a gas refrigerant and a liquid refrigerant by the third gas-liquid separator 11. 4 can be supplied to

  As shown in FIGS. 1 and 2, in the intermediate pressure chamber 5 of the multistage compressor 2, a second injection pipe 23 for injecting refrigerant into the intermediate pressure chamber 5 is provided downstream of the second gas-liquid separator 10. Among the refrigerants that are reduced in pressure to a desired pressure by the second regulating valve 24 and separated into gas refrigerant and liquid refrigerant by the second gas-liquid separator 10, the gas can be supplied to the intermediate pressure chamber 5. It is configured.

  As shown in FIGS. 1 and 2, the high-stage compression mechanism 6 of the multistage compressor 2 includes a first injection pipe 25 for injecting refrigerant into the high-stage compression mechanism 6. 9, the first pressure regulating valve 26 is depressurized to a desired pressure, and the first gas-liquid separator 9 separates the gas into a liquid refrigerant and a gas refrigerant. 6 is configured so that it can be supplied.

  The pressure of the refrigerant injected from the third injection pipe 21 to the low-stage compression mechanism 4 is adjusted to be not less than the suction pressure from the suction pipe 14 and not more than the refrigerant pressure (intermediate pressure) in the intermediate pressure chamber 5. Further, the pressure of the refrigerant injected into the intermediate pressure chamber 5 from the second injection pipe 23 is adjusted to be equal to or higher than the intermediate pressure of the intermediate pressure chamber 5 and lower than the pressure of the refrigerant injected into the high-stage compression mechanism 6. . Further, the pressure of the refrigerant injected from the first injection pipe 25 into the high-stage compression mechanism 6 is adjusted to be not less than the intermediate pressure in the intermediate pressure chamber 5 and not more than the discharge pressure from the discharge pipe 7.

  Note that the injection refrigerant in the refrigeration cycle 1 may be in a wet state due to the balance between the injection flow rate and the amount of generated gas.

  The third injection pipe 21, the second injection pipe 23, and the first injection pipe 25 can respectively inject a refrigerant having an appropriate pressure into the low stage compression mechanism 4, the intermediate pressure chamber 5, and the high stage compression mechanism 6. The configuration of the pipes 21, 23, 25 in the refrigeration cycle 1 may be other than the configuration shown in FIG. For example, a supercooling cycle such as the refrigeration cycle 1A shown in FIG. 37 may be used.

  As shown in FIG. 37, in the refrigeration cycle 1A that is a supercooling cycle, the first injection pipe 25 is connected to the refrigerant pipe 19 downstream of the radiator 8, and the refrigerant cooled by the radiator 8 is introduced. In the refrigerant pipe 19, the first internal heat exchanger 15 is provided on the downstream side of the connection position with the first injection pipe 25. The first internal heat exchanger 15 includes a refrigerant in the refrigerant pipe 19 output from the radiator 8 and a refrigerant after being reduced to a desired pressure by the first adjustment valve 26 provided in the first injection pipe 25. Heat exchange between them. Thereby, the refrigerant flowing through the refrigerant pipe 19 can promote the transition to the left side on the ph diagram to improve the efficiency of the refrigeration cycle 1A, and the refrigerant injected from the first injection pipe 25 to the high-stage compression mechanism 6. The degree of wetness or dryness can be adjusted.

  In the refrigeration cycle 1 </ b> A, the second injection pipe 23 is connected to the refrigerant pipe 19 downstream of the first internal heat exchanger 15, and the refrigerant cooled by the first internal heat exchanger 15 is introduced. In the refrigerant pipe 19, a second internal heat exchanger 16 is provided on the downstream side of the connection position with the second injection pipe 23. After the second internal heat exchanger 16 is depressurized to a desired pressure by the refrigerant in the refrigerant pipe 19 output from the first internal heat exchanger 15 and the second regulating valve 24 provided in the second injection pipe 23. Heat exchange with other refrigerants. Thereby, the refrigerant flowing through the refrigerant pipe 19 can promote the transition to the left side on the ph diagram to improve the efficiency of the refrigeration cycle 1A, and the wetness of the refrigerant injected from the second injection pipe 23 into the intermediate pressure chamber 5 Or the degree of drying can be adjusted.

  In the refrigeration cycle 1 </ b> A, the third injection pipe 21 is connected to the refrigerant pipe 19 downstream of the second internal heat exchanger 16, and the refrigerant cooled by the second internal heat exchanger 16 is introduced. In the refrigerant pipe 19, a third internal heat exchanger 17 is provided on the downstream side of the connection position with the third injection pipe 21. After the third internal heat exchanger 17 is depressurized to a desired pressure by the refrigerant in the refrigerant pipe 19 output from the second internal heat exchanger 16 and the third adjustment valve 22 provided in the third injection pipe 21. Heat exchange with other refrigerants. Thereby, the refrigerant flowing through the refrigerant pipe 19 can promote the transition to the left side on the ph diagram to improve the efficiency of the refrigeration cycle 1A, and the refrigerant injected from the third injection pipe 21 to the low-stage compression mechanism 4 The degree of wetness or dryness can be adjusted.

  Furthermore, in the refrigeration cycle 1 </ b> A, a fourth internal heat exchanger 18 is provided downstream of the third internal heat exchanger 17. The fourth internal heat exchanger 18 exchanges heat between the refrigerant in the refrigerant pipe 19 output from the third internal heat exchanger 17 and the low-temperature refrigerant output from the evaporator 13 and flowing through the suction pipe 14. Thereby, the refrigerant flowing through the refrigerant pipe 19 can promote the transition to the left side on the ph diagram to improve the efficiency of the refrigeration cycle 1A, and the wetness of the refrigerant sucked into the low-stage compression mechanism 4 from the suction pipe 14 Or the degree of drying can be adjusted.

  Moreover, also when using the supercooling cycle of FIG. 37, the injection refrigerant | coolant in 1 A of refrigerating cycles may become a wet state by the relationship between the injection flow volume and the amount of generated gas similarly to the structure shown in FIG.

  When the refrigeration cycle 1A shown in FIG. 37 is used, the pressure of the refrigerant to be injected is a desired pressure within the range of the discharge pressure of the high-stage compression mechanism 6 or the suction pressure of the low-stage compression mechanism 4. However, it is desirable to set it similarly to the refrigeration cycle 1 of FIG.

  With reference to FIG.3 and FIG.4, the specific structure of the multistage compressor 2 is demonstrated. The multistage compressor 2 includes a scroll type two-stage compression mechanism 40 (hereinafter also referred to as “scroll type compression mechanism”) in which the compression unit of one scroll type compression mechanism is divided into two stages. . Hereinafter, the vertical direction in FIG. 3 will be described as the vertical direction.

  As shown in FIG. 3, in the multistage compressor 2 of the present embodiment, a scroll type two-stage compression mechanism 40 is installed in a lower part of the hermetic housing 3, and a scroll type two-stage compression mechanism is arranged in an upper part of the hermetic housing 3. In this configuration, an electric motor 31 (power generation means) that is a drive source of 40 is installed.

  The electric motor 31 has a rotor 32 and a stator 33, and an output shaft 34 is integrally coupled to the rotor 32. The lower end of the output shaft 34 is connected to the movable scroll 43 of the scroll type two-stage compression mechanism 40, and serves as a rotational drive source for the movable scroll 43.

  As shown in FIGS. 3 and 4, the scroll-type two-stage compression mechanism 40 is opposed to both the substantially circular pair of fixed scrolls 41 and 42 and the fixed scrolls 41 and 42 arranged to face each other. And a movable scroll 43 provided so as to be turnable between the fixed scrolls 41 and 42. The fixed scroll 41 is disposed on the upper side of the sealed housing 3 and the fixed scroll 42 is disposed on the lower side of the sealed housing. The scroll type two-stage compression mechanism 40 shown in FIGS. 3 and 4 has a low-stage-side compression mechanism 4 and a high-stage-side compression on one side of the substrate 43A of the movable scroll 43 (the lower fixed scroll 42 side in FIG. 3). The mechanism 6 is arranged.

  The fixed scroll 42 is provided with a partition portion 44 that divides the compression chamber into two stages. The low-stage compression mechanism 4 is formed by an outer lap portion 45 of the fixed scroll 42 and an outer lap portion 46 of the movable scroll 43. The compression chamber 4a of the high-stage compression mechanism 6 is configured by the inner lap portion 47 of the fixed scroll 42 and the inner lap portion 48 of the movable scroll 43.

  The fixed scroll 42 is provided with a bypass passage 49 for connecting the compression chamber 4a and the compression chamber 6a in series, and the suction pipe 14 is connected to the suction side of the low-stage compression mechanism 4 so that the high-stage compression mechanism is connected. A discharge pipe 7 is connected to the discharge side of 6. The intermediate pressure chamber 5 is configured by the bypass passage 49.

  As shown in FIG. 3, a third injection pipe 21 for injecting refrigerant is connected to the compression chamber 4 a of the low-stage compression mechanism 4. A second injection pipe 23 for injecting refrigerant is connected to the bypass passage 49 serving as the intermediate pressure chamber 5. A first injection pipe 25 for injecting refrigerant is connected to the compression chamber 6 a of the high-stage compression mechanism 6.

  The sealed housing 3 that accommodates the scroll type two-stage compression mechanism 40, the electric motor 31 and the like is configured as a container that is completely sealed from an external space by welding and joining a plurality of members. . The internal space SP formed inside the sealed housing 3 is filled with the refrigerant supplied from the suction pipe 14 (that is, the refrigerant sucked by the low-stage compression mechanism 4). For this reason, the internal space SP in the present embodiment is an “internal suction pressure space”. The intermediate pressure chamber 5 that connects the compression chamber 4a and the compression chamber 6a is formed as a space separated from the internal suction pressure space.

  In addition, although the airtight housing 3 may be comprised by welding and joining a some member as mentioned above, you may be comprised by connecting a some member via a gasket. In other words, the sealed housing 3 may be configured as a so-called “semi-sealed” housing.

  Next, the effect of the multistage compressor 2 according to the present embodiment will be described.

  The multistage compressor 2 of the present embodiment is compressed by the hermetic housing 3, the lower stage compression mechanism 4 that is accommodated in the hermetic housing 3, and sucks refrigerant from the refrigeration cycle 1, and the lower stage compression mechanism 4. A plurality of compression mechanisms including at least two stages including a high-stage compression mechanism 6 that sucks and compresses the refrigerant, and the refrigeration cycle 1 is provided in the low-stage compression mechanism 4 (specifically, the compression chamber 4a). The refrigerant extracted from is injected.

  With this configuration, the low-stage compression mechanism 4 that first compresses the refrigerant sucked from the refrigeration cycle 1 among the plurality of compression mechanisms, that is, the compression mechanism with the smallest pressure in the compression chamber, is injected, so the low compression ratio Injection can be performed well even during operation. Thereby, injection can be implemented suitably irrespective of a driving | running state, and efficiency can be improved.

  The multi-stage compressor 2 of the present embodiment is formed separately from the internal suction pressure space that houses the low-stage compression mechanism 4 and the high-stage compression mechanism 6 in the sealed housing 3. An intermediate pressure chamber 5 connected to the high-stage compression mechanism 6 and configured to allow passage of refrigerant discharged from the low-stage compression mechanism 4 and sucked into the high-stage compression mechanism 6 is provided. A noise reduction effect due to pulsation reduction can be expected by providing a throttle in the passage of the intermediate pressure chamber 5 to provide a muffler effect.

  With this configuration, the intermediate pressure refrigerant compressed by the low-stage compression mechanism 4 is not discharged into the sealed housing 3 (that is, the internal space SP), so the inside of the sealed housing 3 does not become an intermediate pressure. Thereby, since the inside of the sealed housing 3 can be kept at a low pressure, the plate thickness of the sealed housing 3 can be reduced to reduce the weight. Further, by keeping the inside of the hermetic housing 3 at a low pressure, the temperature rise of the electric motor 31 in the hermetic housing 3 can be suppressed, and the advantage that the reduction in motor efficiency can be prevented is also obtained. As a result, the efficiency of the multistage compressor 2 can be improved. Further, in the case of the configuration not including the intermediate pressure chamber 5, since the refrigerant containing oil is discharged into the hermetic housing 3, a mechanism for supplying lubricating oil exclusively for lubrication of the high-stage compression mechanism 6 is required. Although the cost may increase, the multistage compressor 2 of the present embodiment can avoid this problem by providing the intermediate pressure chamber 5.

  In the multistage compressor 2 of the present embodiment, the refrigeration cycle 1 is connected to the intermediate pressure chamber 5 through which the refrigerant discharged from the low-stage compression mechanism 4 and sucked into the high-stage compression mechanism 6 is passed in the sealed housing 3. The extracted refrigerant is injected. With this configuration, since the intermediate pressure chamber 5 is injected in addition to the low-stage compression mechanism 4, the efficiency of the multistage compressor 2 can be further improved.

  In the multistage compressor 2 of the present embodiment, the refrigerant extracted from the refrigeration cycle is injected into the high stage compression mechanism 6 (specifically, the compression chamber 6a). With this configuration, since the high stage compression mechanism 6 is injected in addition to the low stage compression mechanism 4 and the intermediate pressure chamber 5, the efficiency of the multistage compressor can be further improved.

  Moreover, in the multistage compressor 2 of this embodiment, since a some compression mechanism is the scroll type two stage compression mechanism 40, compression of a refrigerant | coolant can be performed efficiently and the efficiency of the multistage compressor 2 can be improved.

  In the multistage compressor 2 of the present embodiment, the scroll type two-stage compression mechanism 40 combines the compression chambers 4a and 6a of the low-stage compression mechanism 4 and the high-stage compression mechanism 6 on one side of the substrate 43A. Have. With this configuration, the compression mechanism can be reduced in size. Moreover, the advantage that the processing becomes easy and the tip clearance management in assembling becomes easy, and the advantage that the cost can be reduced can be obtained.

Further, in the multistage compressor 2 of the present embodiment, the refrigerant is because a carbon dioxide (CO _2), and it is possible to perform heat exchange in the refrigeration cycle 1 efficiently. In addition, when the refrigerant is carbon dioxide, the refrigerant tends to be high pressure and high temperature. For this reason, the above-described effects obtained in the first embodiment, that is, the effects of reducing the weight of the sealed housing 3 and improving the efficiency of the electric motor 31 by performing the injection and reducing the internal space SP are increased.

  A plurality of modifications of the first embodiment will be described with reference to FIGS. In describing the respective modifications shown in each of FIGS. 5 to 17, differences from the first embodiment will be mainly described, and descriptions of points common to the first embodiment will be omitted as appropriate.

  In the modified example shown in FIG. 5, the first injection pipe 25 is not connected to the high-stage compression mechanism 6, and the high-stage compression mechanism 6 is configured not to perform refrigerant injection. The low-stage compression mechanism 4 is injected with refrigerant through the third injection pipe 21 and the intermediate pressure chamber 5 is injected with refrigerant through the second injection pipe 23. This is the same as in the first embodiment. As described above, the refrigerant may be injected only into the low-stage compression mechanism 4 and the intermediate pressure chamber 5.

  In the modification shown in FIG. 6, as in the modification of FIG. 5, the first injection pipe 25 is not connected to the high-stage compression mechanism 6, and refrigerant is injected into the high-stage compression mechanism 6. The structure is not broken. Further, the second injection pipe 23 is not connected to the intermediate pressure chamber 5, and the refrigerant is not injected into the intermediate pressure chamber 5. The low-stage compression mechanism 4 is similar to the first embodiment in that the refrigerant is injected through the third injection pipe 21. In this way, the refrigerant may be injected only into the low-stage compression mechanism 4.

  In the modified example shown in FIG. 7, the second injection pipe 23 is not connected to the intermediate pressure chamber 5 and the refrigerant is not injected into the intermediate pressure chamber 5, as in the modified example of FIG. 6. It has become. The low-stage compression mechanism 4 is injected with refrigerant through the third injection pipe 21, and the high-stage compression mechanism 6 is injected with refrigerant through the first injection pipe 25. This is the same as in the first embodiment. Thus, it is good also as a structure by which the injection of a refrigerant | coolant is performed only to each of the low stage side compression mechanism 4 and the high stage side compression mechanism 6. FIG.

  The multistage compressor 2 shown in each of FIGS. 5 to 7 is the multistage compressor of the above embodiment in that the low pressure refrigerant is injected into the low stage compression mechanism 4 and the intermediate pressure chamber 5 is provided. Features common to the machine 2. For this reason, the effect | action and effect similar to said 1st Embodiment can be show | played.

  In the first embodiment and the modifications described above, the multi-stage compressor 2 is configured to include the intermediate pressure chamber 5 between the low-stage side compression mechanism 4 and the high-stage side compression mechanism 6. Instead of such a configuration, a configuration in which the multistage compressor 2 does not include the intermediate pressure chamber 5 as in modified examples of FIGS. In such a configuration, the low-stage compression mechanism 4 discharges the refrigerant into the sealed housing 3 (internal space SP). As a result, the internal space SP is filled with the intermediate pressure refrigerant. That is, the internal space SP is an internal intermediate pressure space through which the refrigerant discharged from the low-stage compression mechanism 4 and sucked into the high-stage compression mechanism 6 passes.

  In the modification shown in FIG. 8, the intermediate pressure chamber 5 is not provided as described above, and the refrigerant is injected into the low-stage compression mechanism 4 via the third injection pipe 21. In this modification, the refrigerant is not injected into the high-stage compression mechanism 6 via the first injection pipe 25 and the refrigerant is not injected via the second injection pipe 23. In this way, the refrigerant may be injected only into the low-stage compression mechanism 4.

  In the modification shown in FIG. 9, in addition to the configuration shown in FIG. 8, the refrigerant is injected into the internal space SP filled with the intermediate pressure refrigerant, that is, the internal intermediate pressure space via the second injection pipe 23. It is configured to be performed. In such a configuration, since the low-temperature refrigerant is injected into the internal intermediate pressure space in which the electric motor 31 is accommodated, the operation efficiency of the electric motor 31 can be improved and the reliability can be ensured.

  In the modification shown in FIG. 10, in addition to the configuration shown in FIG. 8, the refrigerant is injected into the high-stage compression mechanism 6 via the first injection pipe 25. On the other hand, the refrigerant is not injected into the internal intermediate pressure space via the second injection pipe 23. As described above, the refrigerant may be injected only in the low-stage compression mechanism 4 and the high-stage compression mechanism 6 and the refrigerant may not be injected into the internal intermediate pressure space.

  In the modification shown in FIG. 11, in addition to the configuration shown in FIG. 10, the refrigerant is injected into the internal intermediate pressure space via the second injection pipe 23. As described above, the refrigerant may be injected into the low-stage compression mechanism 4, the internal intermediate pressure space, and the high-stage compression mechanism 6.

  In the modification shown in FIG. 12, in addition to the configuration shown in FIG. 8, a reed valve 72 (check valve) is provided in the middle of the path through which the refrigerant is injected from the third injection pipe 21 to the low-stage compression mechanism 4. Is provided. The reed valve 72 allows the refrigerant to flow from the third injection pipe 21 to the low-stage compression mechanism 4 side, while flowing out from the low-stage compression mechanism 4 to the third injection pipe 21 side. This prevents the flow of the refrigerant. By providing the reed valve 72, a situation in which the refrigerant flows backward from the low-stage compression mechanism 4 to the third injection pipe 21 side is prevented. As a result, it is possible to prevent a decrease in operating efficiency due to the backflow.

  In the modification shown in FIG. 13, in addition to the configuration shown in FIG. 9, a configuration in which a reed valve 72 is provided in the middle of a path through which refrigerant is injected from the third injection pipe 21 to the low-stage compression mechanism 4. It has become. The reed valve 72 is the same as that described with reference to FIG. As described above, even in the configuration in which the refrigerant is injected into both the low-stage compression mechanism 4 and the internal intermediate pressure space, the reverse flow of the refrigerant from the low-stage compression mechanism 4 can be prevented by providing the reed valve 72. Can do.

  Such a reed valve 72 can also be employed in the multistage compressor 2 having a configuration including the intermediate pressure chamber 5.

  In the modification shown in FIG. 14, in addition to the configuration shown in FIG. 6, a configuration in which a reed valve 72 is provided in the middle of a path through which refrigerant is injected from the third injection pipe 21 to the low-stage compression mechanism 4. It has become. As described above, even in a configuration in which the intermediate pressure chamber 5 is provided and the internal space SP becomes the internal suction pressure space, the reverse flow of the refrigerant from the low-stage compression mechanism 4 is prevented by providing the reed valve 72. can do.

  In the modification shown in FIG. 15, in addition to the configuration shown in FIG. 5, a configuration in which a reed valve 72 is provided in the middle of a path through which refrigerant is injected from the third injection pipe 21 to the low-stage compression mechanism 4. It has become. Thus, even in a configuration in which refrigerant is injected into both the low-stage compression mechanism 4 and the intermediate pressure chamber 5, the reverse flow of the refrigerant from the low-stage compression mechanism 4 can be prevented by providing the reed valve 72. Can do.

  In the modification shown in FIG. 16, in addition to the configuration shown in FIG. 2, a configuration in which a reed valve 72 is provided in the middle of a path through which refrigerant is injected from the third injection pipe 21 to the low-stage compression mechanism 4. It has become. In addition, a reed valve 92 is provided in the middle of the path through which the refrigerant is injected from the first injection pipe 25 to the high-stage compression mechanism 6. The reed valve 92 allows the refrigerant to flow from the first injection pipe 25 to the high-stage compression mechanism 6 side, while flowing out from the high-stage compression mechanism 6 to the first injection pipe 25 side. This prevents the flow of the refrigerant. By providing the reed valve 92, a situation in which the refrigerant flows backward from the high-stage compression mechanism 6 to the first injection pipe 25 side is prevented.

  As described above, the reed valves 72 and 92 may prevent the refrigerant backflow from the low-stage compression mechanism 4 and the refrigerant backflow from the high-stage compression mechanism 6, respectively.

  In the first embodiment described above and the modifications thereof, the internal space SP is configured to be filled with a refrigerant having a suction pressure or an intermediate pressure. Instead of such an aspect, the internal space SP may be filled with the refrigerant discharged from the high-stage compression mechanism 6. In other words, the internal space SP may be an internal discharge pressure space. The reed valve may be replaced with another check valve such as a poppet valve or a spool valve.

  In the modification shown in FIG. 17, as described above, the refrigerant is discharged from the high-stage compression mechanism 6 to the internal space SP. The refrigerant flows from the internal space SP into the discharge pipe 7 and travels through the discharge pipe 7 to the radiator 8. Thus, also in the multistage compressor 2 in which the internal space SP becomes the internal discharge pressure space, the refrigerant is injected from the third injection pipe 21 to the low-stage compression mechanism 4, and in the first embodiment, The same effect as described can be obtained.

  The second embodiment will be described with reference to FIGS. As will be described below, the scroll type two-stage compression mechanism 40 shown in FIGS. 3 and 4 can be replaced with another configuration.

  As shown in FIGS. 18 to 20, in the multistage compressor 2 </ b> A according to the second embodiment, the scroll type two-stage compression mechanism 50 is provided on one surface side of the substrate 53 </ b> A of the movable scroll 53 (upward fixed in FIG. 18). The low-stage compression mechanism 4 is disposed on the scroll 51 side, and the high-stage compression mechanism 6 is disposed on the other surface side of the substrate 53A (the lower fixed scroll 52 side in FIG. 18). .

  As shown in FIGS. 18 and 19, the lower wrap side is provided by a spiral wrap portion 55 provided on the fixed scroll 51 and a spiral wrap portion 56 erected on one surface of the substrate 53 </ b> A of the movable scroll 53. A compression chamber 4a of the compression mechanism 4 is configured. Similarly, as shown in FIGS. 18 and 20, a spiral wrap portion 57 provided in the fixed scroll 52 and a spiral wrap portion 58 erected on the other surface of the substrate 53A of the movable scroll 53 are used. A compression chamber 6a of the high stage compression mechanism 6 is configured.

  The fixed scroll 51 and the fixed scroll 52 are provided with a bypass passage 59 for connecting the compression chamber 4a and the compression chamber 6a in series, and the suction pipe 14 is connected to the suction side of the low-stage compression mechanism 4 so that the A discharge pipe 7 is connected to the discharge side of the stage side compression mechanism 6. This bypass passage 59 constitutes the intermediate pressure chamber 5.

  As shown in FIG. 18, a third injection pipe 21 for injecting refrigerant is connected to the compression chamber 4 a of the low-stage compression mechanism 4. A second injection pipe 23 for injecting refrigerant is connected to the bypass passage 59 serving as the intermediate pressure chamber 5. A first injection pipe 25 for injecting refrigerant is connected to the compression chamber 6 a of the high-stage compression mechanism 6.

  As described above, in the multistage compressor 2A according to the second embodiment, the scroll type two-stage compression mechanism 50 includes the compression chamber 4a of the low-stage side compression mechanism 4 and the compression chamber 6a of the high-stage side compression mechanism 6 as a substrate 53A. Divided into two sides. With this configuration, it is possible to perform compression on the low-stage side and the high-stage side with a single compression mechanism, so that the compression mechanism can be reduced in size. Moreover, in such a structure, the advantage that a trunk diameter can be made small is also acquired. Furthermore, since the thrust loads of the compression chambers 4a and 6a are opposed to each other, the load applied to the thrust bearing can be reduced, and as a result, an advantage that the reliability is improved can be obtained.

  A third embodiment will be described with reference to FIG. In the multi-stage compressor 2B according to the third embodiment, the low-stage compression mechanism 4 and the high-stage compression mechanism 6 are separated from each other by two scroll compression mechanisms 60, 80, and the electric motor 31 is moved up and down. The configuration is arranged on both sides of the direction.

  In the multistage compressor 2B, a scroll type compression mechanism 60 as the low stage side compression mechanism 4 is installed in the lower part of the hermetic housing 3, and a scroll type compression mechanism 80 as the high stage side compression mechanism 6 is installed in the upper part. The electric motor 31 is installed at the center of the hermetic housing 3. The lower end portion of the output shaft 34 of the electric motor 31 is connected to the scroll compression mechanism 60 and serves as a rotational drive source of the scroll compression mechanism 60. An upper end portion of the output shaft 34 of the electric motor 31 is connected to the scroll compression mechanism 80 and serves as a rotational drive source of the scroll compression mechanism 80.

  The scroll compression mechanism 60 includes a fixed scroll 61 and a movable scroll 62. A compression chamber 4 a is defined between the fixed scroll 61 and the movable scroll 62. The compression chamber 4a is gradually reduced in volume while being moved by the rotational movement of the movable scroll 62. The scroll compression mechanism 60 has a low-pressure side inlet 64 and a suction port 65 communicating with the inlet 64. The suction port 65 communicates with the compression chamber 4a in the suction process. The intake pipe 14 of the refrigeration cycle 1 is connected to the inlet 64.

  A discharge port 67 for discharging the refrigerant compressed in the compression chamber 4 a is formed near the center of the fixed scroll 61 of the scroll compression mechanism 60 as the low-stage compression mechanism 4, and communicates with the outlet 66. At one end of the discharge port 67, a relief valve 68 (discharge valve) is provided. The relief valve 68 is configured to be opened when the pressure of the refrigerant in the compression chamber 4a is equal to or higher than a predetermined value, and thereby configured to avoid over-compression of the scroll compression mechanism 60.

  The scroll compression mechanism 60 as the low stage compression mechanism 4 includes an injection mechanism 69 for injecting refrigerant. The injection mechanism 69 can include a third injection pipe 21. The injection mechanism 69 has a passage 70 communicating with the third injection pipe 21 and a port 71 communicating with the compression chamber 4a in the compression process. The third injection pipe 21, the passage 70, and the port 71 define an injection passage.

  The injection mechanism 69 has a reed valve 72 (a check valve). The reed valve 72 is provided on a member that forms a compression mechanism. The reed valve 72 is provided between the passage 70 and the port 71. The reed valve 72 controls the flow of the refrigerant in the injection passage. The reed valve 72 allows the forward flow of the refrigerant from the passage 70 toward the port 71.

  The reed valve 72 prevents the reverse flow of the refrigerant from the port 71 toward the passage 70. Thus, the reed valve 72 functions so as to prevent the reverse flow of the refrigerant from the port 71 toward the passage 70, whereby the reverse flow of the refrigerant to the third injection pipe 21 can be prevented. Further, the reed valve 72 is provided between the passage 70 and the port 71 and is built in the scroll compression mechanism 60 as shown in FIG. Thereby, size reduction of a compression mechanism can be achieved. In such a configuration, since the reed valve 72 is provided at a position relatively close to the compression chamber 4a, the so-called “dead volume” is reduced, and the operation efficiency of the multistage compressor 2 is reduced. The advantage of improvement is also obtained.

  The scroll-type compression mechanism 80 as the high-stage side compression mechanism 6 also has the same configuration as the scroll-type compression mechanism 60, and includes a relief valve 88 that opens when the pressure of the refrigerant in the compression chamber 83 is equal to or higher than a predetermined value. Further, it is configured to avoid over-compression of the scroll type compression mechanism 80, and the reed valve 92 functions to prevent the reverse flow of the refrigerant from the port 90 toward the passage 91, whereby the first injection pipe 25 is provided. The reverse flow of the refrigerant can be prevented.

  Between the outlet 66 of the scroll type compression mechanism 60 as the low stage side compression mechanism 4 and the inlet 84 of the scroll type compression mechanism 80 as the high stage side compression mechanism 6, the intermediate pressure chamber 5 can circulate the refrigerant. It is connected. The intermediate pressure chamber 5 is formed in the sealed housing 3 separately from the internal suction pressure space in which the scroll compression mechanisms 60 and 80 and the electric motor 31 are accommodated. For example, as shown in FIG. 21, the intermediate pressure chamber 5 is provided so as to extend to the vertical position of the scroll compression mechanisms 60, 80 across the electric motor 31 over the vertical direction of the sealed housing 3.

  As described above, the multistage compressor 2B according to the third embodiment includes the electric motor 31 (power generation means) that is housed in the hermetic housing 3 and serves as a drive source for the plurality of compression mechanisms. The low stage compression mechanism 4 is disposed on one side of the electric motor 31, and the high stage compression mechanism 6 is disposed on the other side of the electric motor 31. With this configuration, since the existing scroll compression mechanism can be used as the low-stage compression mechanism 4 and the high-stage compression mechanism 6 of the multistage compressor 2B, the manufacturability can be improved and the production cost can be reduced. In addition, the adoption of the scroll type compression mechanism has an advantage that noise and efficiency can be reduced. Furthermore, since the assembly of the low-stage compression mechanism 4 and the assembly of the high-stage compression mechanism 6 can be performed separately, there is an advantage that the assembly process becomes easy and the cost can be reduced.

  The relief valves 68 and 88 described as elements included in the multistage compressor 2B according to the third embodiment are the multistage compressor 2 according to the first embodiment and the modifications thereof, and the multistage compressor according to the second embodiment. It can also be applied to 2A. Further, instead of providing the relief valves 68 and 88, the number of turns of the spiral wrap portion of the scroll compression mechanisms 60 and 80 is set to one or less to prevent overcompression similarly to the relief valves 68 and 88. It is good also as a structure which can exhibit an effect. If over-compression can be prevented in this way, it is possible to obtain an advantage that damage to the wrap portion is prevented and a decrease in efficiency is prevented.

  The fourth embodiment will be described with reference to FIGS. FIG. 22 is a vertical cross-sectional view of the multistage compressor 2C according to the fourth embodiment, and shows a cross-section XXII-XXII in FIG. FIG. 23 is a view showing a XXIII-XXIII cross section of FIG. FIG. 24 is a view showing a XXIV-XXIV cross section of FIG. 25 and 26 will be described later.

  Similarly to the multistage compressor 2 shown in FIG. 5, the multistage compressor 2 </ b> C is configured such that refrigerant is injected into each of the intermediate pressure chamber 5 and the low stage side compression mechanism 4. As shown in FIG. 22, the multistage compressor 2 </ b> C includes an electric motor 31, a low stage side compression mechanism 4, and a high stage side compression mechanism 6. The electric motor 31 is a drive source for a plurality of compression mechanisms. The configuration of the electric motor 31 is the same as that in the first embodiment described with reference to FIG. The driving force of the electric motor 31 is transmitted to an after-mentioned movable scroll 120 by the output shaft 34, and operates the low stage side compression mechanism 4 and the high stage side compression mechanism 6.

  The low-stage side compression mechanism 4 and the high-stage side compression mechanism 6 are both configured as scroll-type compression mechanisms, as in the first embodiment described above. These compression mechanisms are constituted by fixed scrolls 110 and 130, a movable scroll 120, and a discharge plate 140.

  The fixed scrolls 110 and 130 are members fixed to the hermetic housing 3, and are disposed to face each other at a position below the electric motor 31 in the internal space SP.

  The movable scroll 120 is provided so as to be able to turn between the fixed scroll 110 and the fixed scroll 130. When the electric motor 31 is operating, the movable scroll 120 is turned by the force received from the output shaft 34. As a result, the respective volumes and positions of the compression chamber 4a and the compression chamber 6a described below change, and the refrigerant is compressed. The Oldham ring 150 shown in FIG. 23 prevents the movable scroll 120 from rotating.

  As shown in FIG. 23, a compression chamber 4a of the low-stage side compression mechanism 4 and a compression chamber 6a of the high-stage side compression mechanism 6 are formed between the fixed scroll 130 and the movable scroll 120, respectively. . The compression chamber 4 a is a space formed between the outer wrap portion 131 of the fixed scroll 130 and the outer wrap portion 122 of the movable scroll 120. The compression chamber 6 a is a space formed between the inner lap portion 133 of the fixed scroll 130 and the inner wrap portion 123 of the movable scroll 120. The compression chamber 4a and the compression chamber 6a are partitioned by a partition portion BD.

  A tip seal SL is disposed at the tip of each wrap portion (122 etc.). One or more compression chambers are formed in each of the compression chamber 4a and the compression chamber 6a. The chip seal SL causes refrigerant leakage between the compression chambers formed in the compression chamber 4a and the compression chamber 6a, refrigerant leakage from the low-stage side compression mechanism 4 to the suction side, and from the high-stage side compression mechanism 6 to the intermediate stage. Any refrigerant leakage to (intermediate pressure chamber 5) is suppressed.

  The discharge plate 140 is a plate-like member that is attached to the lower side (the side opposite to the movable scroll 120) of the fixed scroll 130 via a gasket G (see FIG. 25). FIG. 25 is a diagram schematically showing the fixed scroll 130 with the discharge plate 140 removed, as viewed from below. The intermediate pressure chamber 5, the high-stage discharge chamber 924, and the low-stage injection chamber 942 described later are all formed so as to straddle both the discharge plate 140 and the fixed scroll 130.

  As indicated by a dotted line in FIG. 23, the fixed scroll 130 includes a low-stage suction flow path 901, an intermediate pressure chamber 5, a high-stage discharge chamber 924, a high-stage discharge flow path 931, and a low-stage injection flow path. 941, a low-stage injection chamber 942, and an intermediate injection flow path 951 are formed.

  The low stage suction flow path 901 is a flow path for supplying a refrigerant to the compression chamber 4 a of the low stage side compression mechanism 4. Incidentally, although a pipe which is a part of the suction pipe 14 is press-fitted into the low-stage suction flow path 901, the pipe is not shown in FIG. The refrigerant supplied to the low-stage suction channel 901 flows into the compression chamber 4a through the low-stage suction port 911 that is a through hole, and is then compressed by the low-stage side compression mechanism 4.

  The intermediate pressure chamber 5 is formed as a flow path connecting the compression chamber 4a and the compression chamber 6a, as in the first embodiment described above. The refrigerant compressed in the compression chamber 4a flows into the intermediate pressure chamber 5 through the low-stage discharge port 913 that is a through hole, and then flows into the compression chamber 6a through the high-stage suction port 921 that is a through hole. Thereafter, the refrigerant is compressed by the high-stage compression mechanism 6.

  Here, the low-stage discharge port 913 is formed so that the compression chamber tooth bottom or a part of the wrap hole bites in. When two or more compression chambers formed in the low-stage side compression mechanism 4 communicate with each other through the low-stage discharge port 913 when the wrap portion 122 of the movable scroll 120 overlaps the low-stage discharge port 913, The refrigerant leaks and loses. Therefore, in any case, in order to discharge the refrigerant compressed in the compression process without loss, when the wrap portion 122 of the movable scroll 120 overlaps the low-stage discharge port 913, it is fixed by the wrap portion 122 of the movable scroll 120. The low-stage discharge port 913 of the scroll 130 needs to be closed.

  The high-stage discharge chamber 924 is a space formed so as to straddle both the discharge plate 140 and the fixed scroll 130 as a space into which the refrigerant discharged from the compression chamber 6a flows. The refrigerant compressed in the compression chamber 6a flows into the high-stage discharge chamber 924 through the high-stage discharge port 923 that is a through hole.

  The high-stage discharge flow channel 931 is a flow channel for discharging the refrigerant in the high-stage discharge chamber 924, that is, the refrigerant compressed in the compression chamber 6 a toward the discharge pipe 7. In addition, although the pipe which is a part of discharge piping 7 is press-fit in the high stage discharge flow path 931, illustration of the said pipe is abbreviate | omitted in FIG.

  The low-stage injection flow path 941 is a flow path through which the refrigerant injected into the low-stage compression mechanism 4 passes. In addition, although the pipe which is a part of 3rd injection piping 21 is press-fitted in the low stage injection flow path 941, illustration of the said pipe is abbreviate | omitted in FIG. The refrigerant that has passed through the low-stage injection flow path 941 flows into the low-stage injection chamber 942.

  The low-stage injection chamber 942 is a space formed so as to straddle both the discharge plate 140 and the fixed scroll 130 as a space into which the refrigerant that has passed through the low-stage injection flow path 941 flows. The refrigerant that has flowed into the low-stage injection chamber 942 is injected into the compression chamber 4a through the low-stage injection port 943 that is a through hole.

  Further, when the wrap portion 122 of the movable scroll 120 passes through the upper surface of the injection port 943, the injection port 943 is completely movable to prevent leakage between the plurality of compression chambers formed in the compression chamber 4a. The flow path is closed by the wrap portion 122 and the tip seal SL. Therefore, the diameter of the injection port 943 is less than or equal to the plate thickness of the wrap portion 122 of the movable scroll 120, and more preferably less than the width of the tip seal SL. Further, depending on the position of the injection port 943, it is possible to inject continuously and non-simultaneously into a plurality of compression chambers formed in the compression chamber 4a.

  The intermediate injection flow path 951 is a flow path through which the refrigerant injected into the intermediate pressure chamber 5 passes. In addition, although the pipe which is a part of 2nd injection piping 23 is press-fit in the intermediate | middle injection flow path 951, illustration of the said pipe is abbreviate | omitted in FIG. The refrigerant that has passed through the intermediate injection flow path 951 is injected into the intermediate pressure chamber 5.

  Other configurations will be described. As shown in FIG. 24, the fixed scroll 130 is provided with an oil return channel 971 and an oil suction pipe 972.

  The oil return flow path 971 is a flow path for receiving oil (lubricating oil) returned from the outside to the multistage compressor 2 and supplying it between the fixed scroll 130 and the movable scroll 120.

  The oil suction pipe 972 is a pipe for sucking up oil accumulated in the bottom of the sealed housing 3. The upper end of the oil suction pipe 972 is connected to the low stage suction flow path 901. For this reason, when the refrigerant is sucked from the low-stage suction channel 901, the oil accumulated at the bottom of the hermetic housing 3 is sucked by the oil suction pipe 972 and supplied to the low-stage suction channel 901. Thereafter, the oil is used for lubricating each part.

  FIG. 26 is a view showing a XXVI-XXVI cross section of FIG. As shown in the figure, a reed valve 72 is provided at a position between the low-stage injection chamber 942 and the low-stage injection port 943.

  The reed valve 72 has a valve seat 721 and a valve body 722. When the pressure in the low-stage injection chamber 942 is higher than the pressure in the low-stage injection port 943, the valve body 722 is separated from the valve seat 721, and the refrigerant is injected into the compression chamber 4a through the reed valve 72. On the other hand, when the pressure of the low-stage injection port 943 is higher than the pressure of the low-stage injection chamber 942, the valve body 722 is pressed against the valve seat 721 by the pressure. This prevents the refrigerant from flowing backward from the compression chamber 4a side to the low-stage injection chamber 942 side.

  The multistage compressor 2 </ b> C configured as described above also has the same effect as that described in the first embodiment. Further, as in the first embodiment, a check valve other than the reed valve, a poppet valve, or a spool valve may be used.

  A modification of the multistage compressor 2C will be described with reference to FIG. FIG. 27 shows the configurations of the fixed scroll 130 and the movable scroll 120 according to the modification in the same cross section as FIG. As shown in the figure, in this modified example, the tip seal SL is not disposed at the tip of each wrap portion (122 or the like). When leakage of refrigerant from the compression chamber 4a or the compression chamber 6a is not a serious problem, or the refrigerant at the discharge pressure is introduced from the intermediate pressure to the back side of the movable scroll 120 (the surface where the wrap portion 122 is not formed). Such a configuration may be used when the back pressure mechanism is provided.

  The fifth embodiment will be described with reference to FIGS. 28 and 29. FIG. FIG. 28 is a vertical cross-sectional view of a multistage compressor 2D according to the fifth embodiment, showing a cross-section XXVIII-XXVIII in FIG. FIG. 29 is a view showing a XXIX-XXIX cross section of FIG.

  In the multi-stage compressor 2D, similarly to the multi-stage compressor 2 shown in FIG. 2 (that is, the first embodiment), refrigerant is injected into each of the intermediate pressure chamber 5, the low-stage side compression mechanism 4, and the high-stage side compression mechanism 6. It becomes the composition which is done. As shown in FIG. 28, the multistage compressor 2 </ b> D includes an electric motor 31, a low stage side compression mechanism 4, and a high stage side compression mechanism 6. The electric motor 31 is a drive source for a plurality of compression mechanisms. The configuration of the electric motor 31 is the same as that in the first embodiment described with reference to FIG. The driving force of the electric motor 31 is transmitted to a swing member 220 (described later) through the output shaft 34 to operate the low-stage compression mechanism 4 and the high-stage compression mechanism 6.

  In the present embodiment, the low-stage compression mechanism 4 and the high-stage compression mechanism 6 are both configured as swing-type compression mechanisms. These compression mechanisms are constituted by fixing members 210 and 230 and a swing member 220.

  The fixing members 210 and 230 are both members fixed to the hermetic housing 3, and are disposed to face each other at a position below the electric motor 31 in the internal space SP.

  The swing member 220 is provided so as to be able to turn between the fixed member 210 and the fixed member 230. When the electric motor 31 is operating, the swing member 220 is turned by the force received from the output shaft 34. As a result, the respective volumes and positions of the compression chamber 4a and the compression chamber 6a described below change, and the refrigerant is compressed. A thrust bearing 240 is disposed between the swing member 220 and the fixed member 210.

  As shown in FIG. 29, a compression chamber 4a of the low-stage side compression mechanism 4 and a compression chamber 6a of the high-stage side compression mechanism 6 are formed between the fixing member 230 and the swing member 220, respectively. . The compression chamber 4 a is a space formed between the lap portion 231 on the outer peripheral side of the fixing member 230 and the lap portion 221 of the swing member 220. The compression chamber 6 a is a space formed between the inner peripheral side wrap portion 232 of the fixing member 230 and the wrap portion 221 of the swing member 220.

  As shown by a dotted line in FIG. 29, the fixing member 230 includes a low-stage suction flow path 901, an intermediate pressure chamber 5, a high-stage discharge chamber 924, a high-stage discharge flow path 931, and a low-stage injection flow path. 941, an intermediate injection flow path 951, and a high-stage injection flow path 961 are formed. Although not clearly shown in the figure, the flow paths do not merge with each other.

  The low stage suction flow path 901 is a flow path for supplying a refrigerant to the compression chamber 4 a of the low stage side compression mechanism 4. As shown in FIG. 29, a pipe that is a part of the suction pipe 14 is press-fitted into the low-stage suction flow path 901. The refrigerant supplied to the low-stage suction channel 901 flows into the compression chamber 4a through the low-stage suction port 911 that is a through hole, and is then compressed by the low-stage side compression mechanism 4.

  The intermediate pressure chamber 5 is formed as a flow path connecting the compression chamber 4a and the compression chamber 6a, as in the first embodiment described above. The refrigerant compressed in the compression chamber 4a flows into the intermediate pressure chamber 5 through the low-stage discharge port 913 that is a through hole, and then flows into the compression chamber 6a through the high-stage suction port 921 that is a through hole. Thereafter, the refrigerant is compressed by the high-stage compression mechanism 6.

  The high-stage discharge chamber 924 is a space formed in the fixed member 230 as a space into which the refrigerant discharged from the compression chamber 6a flows. The refrigerant compressed in the compression chamber 6a flows into the high-stage discharge chamber 924 through the high-stage discharge port 923 that is a through hole.

  The high-stage discharge flow channel 931 is a flow channel for discharging the refrigerant in the high-stage discharge chamber 924, that is, the refrigerant compressed in the compression chamber 6 a toward the discharge pipe 7. A pipe that is a part of the discharge pipe 7 is press-fitted into the high-stage discharge flow path 931.

  The low-stage injection flow path 941 is a flow path through which the refrigerant injected into the low-stage compression mechanism 4 passes. A pipe that is a part of the third injection pipe 21 is press-fitted into the low-stage injection flow path 941. The refrigerant that has passed through the low-stage injection flow path 941 is injected into the compression chamber 4a through the low-stage injection port 943 that is a through hole. In FIG. 29, a part of the low-stage injection flow path 941 is not shown.

  The intermediate injection flow path 951 is a flow path through which the refrigerant injected into the intermediate pressure chamber 5 passes. A pipe that is a part of the second injection pipe 23 is press-fitted into the intermediate injection flow path 951. The refrigerant that has passed through the intermediate injection flow path 951 is injected into the intermediate pressure chamber 5.

  The high stage injection flow path 961 is a flow path through which the refrigerant injected into the high stage compression mechanism 6 passes. A pipe that is a part of the first injection pipe 25 is press-fitted into the high-stage injection flow path 961. The refrigerant that has passed through the high-stage injection flow path 961 is injected into the compression chamber 6a through the high-stage injection port 963 that is a through hole. In FIG. 29, a part of the high-stage injection flow path 961 is not shown.

  A reed valve 72 as described with reference to FIG. 16 is provided at a position between the low stage injection flow path 941 and the low stage injection port 943. Further, a reed valve 92 as described with reference to FIG. 16 is provided at a position between the high-stage injection flow path 961 and the high-stage injection port 963. However, in FIG. 28 and 29, illustration of these reed valves 72 and 92 is omitted.

  As described above, in the multistage compressor 2D, each of the low-stage side compression mechanism 4 and the high-stage side compression mechanism 6 is configured as a swing type compression mechanism instead of a rotary type. Even in such a configuration, the same effects as those described in the first embodiment can be obtained.

  The sixth embodiment will be described with reference to FIGS. 30 and 31. FIG. 30 is a longitudinal sectional view of a multistage compressor 2E according to the sixth embodiment, and FIG. 31 is a view showing a XXXI-XXXI section of FIG. The cross section shown in FIG. 30 is a cross section passing through each of the low-stage suction flow path 901 and the high-stage discharge flow path 931 shown in FIG. 31, but in order to understand the structure, a part of the cross section is shown. Is depicted in a different manner than it actually is (for example, the position of vane 370).

  Similarly to the multistage compressor 2 shown in FIG. 5, the multistage compressor 2 </ b> E is configured such that refrigerant is injected into each of the intermediate pressure chamber 5 and the low stage side compression mechanism 4. As shown in FIG. 30, the multistage compressor 2 </ b> E includes an electric motor 31, a low stage side compression mechanism 4, and a high stage side compression mechanism 6. The electric motor 31 is a drive source for a plurality of compression mechanisms. The configuration of the electric motor 31 is the same as that in the first embodiment described with reference to FIG. The driving force of the electric motor 31 is transmitted to the ring member 320 (described later) by the output shaft 34 to operate the low stage side compression mechanism 4 and the high stage side compression mechanism 6.

  In the present embodiment, the low-stage compression mechanism 4 and the high-stage compression mechanism 6 are both configured as ring-type compression mechanisms. These compression mechanisms are constituted by fixing members 310, 330, and 350 and a ring member 320.

  The fixed members 310, 330, and 350 are all members fixed to the hermetic housing 3, and are arranged in the vertical direction at a position below the electric motor 31 in the internal space SP. Yes. A cylindrical space is formed inside the fixing member 330. A part of the fixing member 350 is a protruding portion 351 that protrudes upward. A lap portion 321 of the ring member 320 and a protruding portion 351 of the fixing member 350 are accommodated in a space formed inside the fixing member 330.

  The ring member 320 is provided so as to be able to turn in a space formed inside the fixing member 330. When the electric motor 31 is operating, the ring member 320 is turned by the force received from the output shaft 34. As a result, the respective volumes and positions of the compression chamber 4a and the compression chamber 6a described below change, and the refrigerant is compressed. A thrust bearing 340 is disposed between the ring member 320 and the fixed member 310.

  As shown in FIG. 31, the compression chamber 4 a of the low-stage compression mechanism 4 and the compression chamber 6 a of the high-stage compression mechanism 6 are formed inside the fixing member 330, respectively. The compression chamber 4 a is a space formed between the inner peripheral surface of the fixing member 330 and the wrap portion 321 of the ring member 320. The compression chamber 6 a is a space formed between the protruding portion 351 of the fixing member 350 and the wrap portion 321 of the ring member 320.

  A vane 360 protrudes from a part of the inner peripheral surface of the fixing member 330 toward the outer peripheral surface of the lap portion 321. The tip of the vane 360 is pressed against the lap portion 321 by the biasing force of the spring 361. For this reason, the refrigerant in the compression chamber 4a cannot move beyond the vane 360.

  Similarly, a vane 370 protrudes from a part of the outer peripheral surface of the protruding portion 351 toward the inner peripheral surface of the wrap portion 321. The tip of the vane 370 is pressed against the lap portion 321 by the biasing force of the spring 371. For this reason, the refrigerant in the compression chamber 6a cannot move beyond the vane 370.

  As shown in FIGS. 30 and 31, the fixing member 350 includes a low-stage suction flow path 901, an intermediate pressure chamber 5, a high-stage discharge chamber 924, a high-stage discharge flow path 931, and a low-stage injection flow path. 941 and an intermediate injection flow path 951 are formed.

  The low stage suction flow path 901 is a flow path for supplying a refrigerant to the compression chamber 4 a of the low stage side compression mechanism 4. As shown in FIG. 31, a pipe that is a part of the suction pipe 14 is press-fitted into the low-stage suction flow path 901. The refrigerant supplied to the low-stage suction channel 901 flows into the compression chamber 4a through the low-stage suction port 911 that is a through hole, and is then compressed by the low-stage side compression mechanism 4.

  The intermediate pressure chamber 5 is formed as a flow path connecting the compression chamber 4a and the compression chamber 6a, as in the first embodiment described above. The refrigerant compressed in the compression chamber 4a flows into the intermediate pressure chamber 5 through the low-stage discharge port 913 that is a through hole, and then flows into the compression chamber 6a through the high-stage suction port 921 that is a through hole. Thereafter, the refrigerant is compressed by the high-stage compression mechanism 6.

  The high-stage discharge chamber 924 is a space formed in the fixed member 350 as a space into which the refrigerant discharged from the compression chamber 6a flows. The refrigerant compressed in the compression chamber 6a flows into the high-stage discharge chamber 924 through the high-stage discharge port 923 that is a through hole.

The high-stage discharge flow channel 931 is a flow channel for discharging the refrigerant in the high-stage discharge chamber 924, that is, the refrigerant compressed in the compression chamber 6 a toward the discharge pipe 7. A pipe that is a part of the discharge pipe 7 is press-fitted into the high-stage discharge flow path 931. The low-stage injection flow path 941 is a flow path through which the refrigerant injected into the low-stage side compression mechanism 4 passes. A pipe that is a part of the third injection pipe 21 is press-fitted into the low-stage injection flow path 941. The refrigerant that has passed through the low-stage injection flow path 941 is injected into the compression chamber 4a through the low-stage injection port 943 that is a through hole. In FIG. 31, a part of the low-stage injection flow path 941 is not shown.

  The intermediate injection flow path 951 is a flow path through which the refrigerant injected into the intermediate pressure chamber 5 passes. A pipe that is a part of the second injection pipe 23 is press-fitted into the intermediate injection flow path 951. The refrigerant that has passed through the intermediate injection flow path 951 is injected into the intermediate pressure chamber 5.

  A reed valve 72 as described with reference to FIG. 16 is provided at a position between the low stage injection flow path 941 and the low stage injection port 943. However, the reed valve 72 is not shown in FIGS.

  As described above, in the multistage compressor 2E, each of the low-stage side compression mechanism 4 and the high-stage side compression mechanism 6 is configured as a ring-type compression mechanism instead of a rotary type. Even in such a configuration, the same effects as those described in the first embodiment can be obtained.

  The seventh embodiment will be described with reference to FIGS. 32 to 34. FIG. 32 is a longitudinal sectional view of a multistage compressor 2F according to the seventh embodiment, and FIG. 33 is a view showing a XXXIII-XXXIII section of FIG. FIG. 34 will be described later.

  Note that the cross section shown in FIG. 32 is a cross section that passes through each of the low-stage suction flow path 901 and the low-stage injection flow path 941 shown in FIG. Is drawn in a different manner than it actually is.

  Similarly to the multistage compressor 2 shown in FIG. 7, the multistage compressor 2 </ b> F has a configuration in which refrigerant is injected into each of the low-stage side compression mechanism 4 and the high-stage side compression mechanism 6. As shown in FIG. 32, the multistage compressor 2 </ b> E includes an electric motor 31, a low stage side compression mechanism 4, and a high stage side compression mechanism 6. The electric motor 31 is a drive source for a plurality of compression mechanisms. The configuration of the electric motor 31 is the same as that in the first embodiment described with reference to FIG. The driving force of the electric motor 31 is transmitted to a movable scroll 420 and a ring member 470, which will be described later, by the output shaft 34, and operates the low-stage compression mechanism 4 and the high-stage compression mechanism 6.

  In the present embodiment, the low-stage compression mechanism 4 is configured as a scroll-type compression mechanism, and is disposed at a position below the electric motor 31 in the internal space SP of the sealed housing 3. In the present embodiment, the high-stage compression mechanism 6 is configured as a ring-type compression mechanism, and is disposed at a position above the electric motor 31 in the internal space SP of the hermetic housing 3.

  First, the configuration of the low-stage compression mechanism 4 will be described. The low-stage compression mechanism 4 includes fixed scrolls 410 and 430, a movable scroll 420, and a discharge plate 440.

  The fixed scrolls 410 and 430 are members fixed to the hermetic housing 3, and are arranged to face each other at a position below the electric motor 31 in the internal space SP.

  The movable scroll 420 is provided so as to be able to turn between the fixed scroll 410 and the fixed scroll 430. When the electric motor 31 is operating, the movable scroll 420 is turned by the force received from the output shaft 34. As a result, the volume and position of the compression chamber 4a formed between the fixed scroll 430 and the movable scroll 420 change, and the refrigerant is compressed. The compression chamber 4 a is a space formed between the spiral wrap portion 431 of the fixed scroll 430 and the spiral wrap portion 421 of the movable scroll 420. The specific shape of the compression chamber 4a and its surroundings is obtained by changing the scroll compression mechanism as shown in FIG. 23, for example, from a two-stage type to a one-stage type. For this reason, the detailed illustration and description thereof will be omitted.

  The discharge plate 440 is a plate-like member that is attached to the lower side (the side opposite to the movable scroll 420) of the fixed scroll 430 via a gasket (not shown). FIG. 34 is a diagram schematically showing the fixed scroll 430 with the discharge plate 440 removed, as viewed from the lower side. Both the intermediate pressure chamber 5 and the low-stage injection chamber 942 described later are formed so as to straddle both the discharge plate 440 and the fixed scroll 430.

  As shown in FIGS. 32 and 34, the fixed scroll 430 is formed with a low-stage suction flow path 901, an intermediate pressure chamber 5, a low-stage injection flow path 941, and a low-stage injection chamber 942. Yes.

  The low stage suction flow path 901 is a flow path for supplying a refrigerant to the compression chamber 4 a of the low stage side compression mechanism 4. As shown in FIG. 32, a pipe that is a part of the suction pipe 14 is press-fitted into the low-stage suction flow path 901. The refrigerant supplied to the low stage suction channel 901 flows into the compression chamber 4a and is then compressed by the low stage side compression mechanism 4.

  The intermediate pressure chamber 5 is formed as a flow path connecting the compression chamber 4a and the compression chamber 6a, as in the first embodiment described above. The refrigerant compressed in the compression chamber 4a flows into the intermediate pressure chamber 5 through the low-stage discharge port 913 that is a through hole. As shown in FIG. 32, a relief valve 451 is provided between the low stage discharge port 913 and the intermediate pressure chamber 5. The relief valve 451 is configured to open when the pressure of the refrigerant in the compression chamber 4a is equal to or higher than a predetermined value. Thereby, the overcompression in the low stage side compression mechanism 4 can be avoided.

  The refrigerant that has reached the intermediate pressure chamber 5 is supplied to the high-stage compression mechanism 6 through the connection pipe 5c (partially not shown). In FIG. 34, the flow path 5b which guide | induces a refrigerant | coolant from the intermediate pressure chamber 5 to the connection piping 5c is shown. In the figure, reference numeral 5a denotes an opening formed at an end of the flow path 5b on the intermediate pressure chamber 5 side.

  The low-stage injection flow path 941 is a flow path through which the refrigerant injected into the low-stage compression mechanism 4 passes. A pipe that is a part of the third injection pipe 21 is press-fitted into the low-stage injection flow path 941. The refrigerant that has passed through the low-stage injection flow path 941 flows into the low-stage injection chamber 942.

  The low-stage injection chamber 942 is a space formed so as to straddle both the discharge plate 440 and the fixed scroll 430 as a space into which the refrigerant that has passed through the low-stage injection flow path 941 flows. The refrigerant that has flowed into the low-stage injection chamber 942 is injected into the compression chamber 4a through the low-stage injection port 943 that is a through hole. In the present embodiment, two low-stage injection chambers 942 and two low-stage injection ports 943 are formed.

  A reed valve 72 is provided at a position between each low-stage injection chamber 942 and the low-stage injection port 943. The structure of the reed valve 72 is the same as the structure of the reed valve 72 of the fourth embodiment described with reference to FIG. By providing the reed valve 72, it is possible to prevent the refrigerant from flowing backward from the compression chamber 4a side to the low-stage injection chamber 942 side.

  Next, the configuration of the high stage compression mechanism 6 will be described. The high-stage compression mechanism 6 includes fixed members 460 and 490 and a ring member 470.

  Each of the fixing members 460 and 490 is a member fixed to the hermetic housing 3, and is arranged in a vertically stacked state at a position above the electric motor 31 in the internal space SP. Yes. A cylindrical space is formed inside the fixing member 460. A ring member 470 is accommodated in a space formed inside the fixing member 330.

  The ring member 470 is provided so as to be able to turn in a space formed inside the fixing member 460. When the electric motor 31 is operating, the ring member 470 is turned by the force received from the output shaft 34. Thereby, the volume and position of the compression chamber 6a formed between the inner peripheral surface of the fixing member 460 and the outer peripheral surface of the ring member 470 are changed, and the refrigerant is compressed.

  A vane 480 protrudes from a part of the inner peripheral surface of the fixing member 460 toward the outer peripheral surface of the ring member 470. The tip of the vane 480 is pressed against the ring member 470 by the biasing force of the spring 481. For this reason, the refrigerant in the compression chamber 6a cannot move beyond the vane 480.

  As shown in FIGS. 32 and 33, the fixing member 490 is formed with a high-stage suction flow path 5d, a high-stage discharge flow path 931, and a high-stage injection flow path 961.

  The high stage suction flow path 5d is a flow path for guiding the refrigerant supplied from the low stage side compression mechanism 4 to the connection pipe 5c to the compression chamber 6a. The refrigerant that has passed through the high-stage suction channel 5d flows into the compression chamber 6a through the high-stage suction port 921 that is a through hole. Thereafter, the refrigerant is compressed by the high-stage compression mechanism 6. The refrigerant compressed in the compression chamber 6a flows into the high-stage discharge channel 931 through the high-stage discharge port 923 that is a through hole.

  The high-stage discharge channel 931 is a channel for discharging the refrigerant compressed in the compression chamber 6 a toward the discharge pipe 7. A pipe that is a part of the discharge pipe 7 is press-fitted into the high-stage discharge flow path 931.

  The high stage injection flow path 961 is a flow path through which the refrigerant injected into the high stage compression mechanism 6 passes. A pipe that is a part of the first injection pipe 25 is press-fitted into the high-stage injection flow path 961. The refrigerant that has passed through the high-stage injection flow path 961 is injected into the compression chamber 6a through the high-stage injection port 963 that is a through hole. In FIG. 33, a part of the high-stage injection flow path 961 is not shown.

  As described above, in the multistage compressor 2F, the low-stage compression mechanism 4 is configured as a scroll-type compression mechanism, and the high-stage compression mechanism 6 is configured as a ring-type compression mechanism. The low-stage compression mechanism 4 is disposed below the electric motor 31 (that is, one side of the power generation means), and the high-stage compression mechanism 6 is disposed above the electric motor 31 (that is, the other side of the power generation means). It is the composition arranged in. Even in such a configuration, the same effects as those described in the first embodiment can be obtained.

  The eighth embodiment will be described with reference to FIGS. 35 and 36. FIG. 35 is a longitudinal sectional view of a multistage compressor 2G according to the eighth embodiment, and FIG. 36 is a view showing a XXXVI-XXXVI section of FIG. In addition, as shown in FIG. 35, the XXXVI-XXXVI cross section is not a flat cross section as a whole, the inner portion is a low cross section, and the outer portion is a high cross section. . In FIG. 36, the boundary between the low-position cross section and the high-position cross section is indicated by a curve with a symbol BL.

  Similarly to the multistage compressor 2 shown in FIG. 5, the multistage compressor 2 </ b> F has a configuration in which refrigerant is injected into each of the intermediate pressure chamber 5 and the low-stage compression mechanism 4. As shown in FIG. 35, the multistage compressor 2 </ b> F includes an electric motor 31, a low stage side compression mechanism 4, and a high stage side compression mechanism 6. The electric motor 31 is a drive source for a plurality of compression mechanisms. The configuration of the electric motor 31 is the same as that in the first embodiment described with reference to FIG. The driving force of the electric motor 31 is transmitted to a movable member 520, which will be described later, through the output shaft 34, and operates the low-stage compression mechanism 4 and the high-stage compression mechanism 6.

  The low-stage compression mechanism 4 is configured as a ring-type compression mechanism in the present embodiment. Further, the high-stage compression mechanism 6 is configured as a scroll-type compression mechanism in the present embodiment. These compression mechanisms are constituted by fixed members 510 and 530, a discharge plate 540, and a movable member 520.

  Each of the fixing members 510 and 530 is a member fixed to the hermetic housing 3 and is disposed so as to face each other at a position below the electric motor 31 in the internal space SP. A recess that recedes downward is formed on the upper surface of the fixed member 530, and a part of the movable member 520 is accommodated in the recess.

  The discharge plate 540 is a plate-like member attached to a lower surface (opposite side of the movable member 520) of the fixed member 530 via a gasket (not shown). Both the intermediate pressure chamber 5 and the high-stage discharge chamber 924 described later are formed so as to straddle both the discharge plate 540 and the fixing member 530.

  The movable member 520 is provided so as to be able to turn in the concave portion of the movable member 520. When the electric motor 31 is operating, the movable member 520 is turned by the force received from the output shaft 34. As a result, the respective volumes and positions of the compression chamber 4a and the compression chamber 6a described below change, and the refrigerant is compressed. A thrust bearing 340 is disposed between the movable member 520 and the fixed member 510.

  Four rotation prevention protrusions 570 projecting upward are provided on the upper surface of the fixing member 510. A concave portion 571 that recedes upward is formed in a portion of the lower surface of the movable member 520 that faces the rotation prevention protrusion 570, and the rotation prevention protrusion 570 is accommodated in the recess 571. The inner diameter of the recess 571 is larger than the outer diameter of the rotation prevention protrusion 570. For this reason, while the movable member 520 is allowed to turn, it is prevented from rotating.

  The movable member 520 includes a substantially disc-shaped disc portion 521 and a wrap portion 522 that projects downward from the lower surface of the disc portion 521. A space formed between the outer peripheral surface of the disc portion 521 and the inner peripheral surface of the recess formed in the fixing member 530 is a compression chamber 4a of the low-stage compression mechanism 4 in the present embodiment.

  A wrap portion 531 that protrudes upward is formed on the bottom surface of the recess formed in the fixing member 530. A space formed between the wrap portion 522 of the movable member 520 and the wrap portion 531 of the fixed member 530 is a compression chamber 6a of the high-stage compression mechanism 6 in the present embodiment. As shown in FIG. 35, the concave portion formed in the fixing member 530 has a stepped shape such that the central portion thereof further recedes downward. For this reason, the compression chamber 4a and the compression chamber 6a are not directly connected to each other, and the both are partitioned by a portion where the disc portion 521 and the movable member 520 of the fixed member 530 contact each other.

  A vane 560 protrudes from a part of the inner peripheral surface of the fixing member 530 toward the outer peripheral surface of the disc portion 521. The tip of the vane 560 is pressed against the disc portion 521 by the biasing force of the spring 561. For this reason, the refrigerant in the compression chamber 4a cannot move beyond the vane 560.

  In the lower portion of the fixed member 530, a low-stage suction flow path 901, an intermediate pressure chamber 5, a high-stage discharge chamber 924, a high-stage discharge flow path 931, and a low-stage injection flow path 941 (not shown). And an intermediate injection flow path 951 is formed.

  The low stage suction flow path 901 is a flow path for supplying a refrigerant to the compression chamber 4 a of the low stage side compression mechanism 4. A pipe which is a part of the suction pipe 14 is press-fitted into the low-stage suction flow path 901, but the pipe is not shown in FIG. The refrigerant supplied to the low stage suction channel 901 flows into the compression chamber 4a and is then compressed by the low stage side compression mechanism 4.

  The intermediate pressure chamber 5 is formed as a flow path connecting the compression chamber 4a and the compression chamber 6a, as in the first embodiment described above. The refrigerant compressed in the compression chamber 4a flows into the intermediate pressure chamber 5 through the low-stage discharge port 913 that is a through hole, and then flows into the compression chamber 6a through the high-stage suction port 921 that is a through hole. Thereafter, the refrigerant is compressed by the high-stage compression mechanism 6.

  The high-stage discharge chamber 924 is a space formed so as to straddle both the discharge plate 540 and the fixing member 530 as a space into which the refrigerant discharged from the compression chamber 6a flows. The refrigerant compressed in the compression chamber 6a flows into the high-stage discharge chamber 924 through the high-stage discharge port 923 that is a through hole.

  A relief valve 88 is provided at a position between the high stage discharge port 923 and the high stage discharge chamber 924. The relief valve 88 is a valve configured to open when the pressure of the refrigerant in the compression chamber 6a is equal to or higher than a predetermined value. By providing the relief valve 88, over-compression in the high-stage compression mechanism 6 and back flow of refrigerant from the high-stage discharge chamber 924 toward the compression chamber 6a are prevented.

  The high-stage discharge flow channel 931 is a flow channel for discharging the refrigerant in the high-stage discharge chamber 924, that is, the refrigerant compressed in the compression chamber 6 a toward the discharge pipe 7. A pipe which is a part of the discharge pipe 7 is press-fitted into the high-stage discharge flow channel 931, but the illustration thereof is omitted in FIG.

  The low-stage injection flow path 941 (not shown) is a flow path through which the refrigerant injected into the low-stage compression mechanism 4 passes. A pipe that is a part of the third injection pipe 21 is press-fitted into the low-stage injection flow path 941. The refrigerant that has passed through the low-stage injection flow path 941 is injected into the compression chamber 4a through a low-stage injection port 943 (see FIG. 36) that is a through hole.

  The intermediate injection flow path 951 is a flow path through which the refrigerant injected into the intermediate pressure chamber 5 passes. A pipe which is a part of the second injection pipe 23 is press-fitted into the intermediate injection flow path 951, but the illustration thereof is omitted in FIG. The refrigerant that has passed through the intermediate injection flow path 951 is injected into the intermediate pressure chamber 5.

  As described above, in the multistage compressor 2G, the low-stage compression mechanism 4 is configured as a ring-type compression mechanism, and the high-stage compression mechanism 6 is configured as a scroll-type compression mechanism. Further, such a low-stage compression mechanism 4 and a high-stage compression mechanism 6 are configured by common parts (movable member 520 and fixed member 530). Even in such a configuration, the same effects as those described in the first embodiment can be obtained.

  As in each of the embodiments described above, various types of compression mechanisms can be employed as the low-stage compression mechanism 4 and the high-stage compression mechanism 6. In addition to the examples given in the above description, for example, a reciprocating compression mechanism instead of a rotary type may be adopted.

  In the above description, the two-stage compressor having the low-stage side compression mechanism 4 and the high-stage side compression mechanism 6 is given as an example of the multistage compressors 2, 2A, 2B, 2C, 2D, 2E, 2F, 2G. A configuration having three or more stages of compressors may be used.

  The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Those in which those skilled in the art appropriately modify the design of these specific examples are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the specific examples described above and their arrangement, conditions, shape, and the like are not limited to those illustrated, and can be changed as appropriate. Each element included in each of the specific examples described above can be appropriately combined as long as no technical contradiction occurs.

1, 1A: Refrigeration cycle 2, 2A, 2B, 2C, 2D, 2E, 2F, 2G: Multistage compressor 3: Sealed housing 4: Low stage compression mechanism 6: High stage compression mechanism

Claims (14)

A sealed housing (3);
A low-stage compression mechanism (4) that is housed in the hermetic housing and sucks refrigerant from the refrigeration cycle (1, 1A), and a high-stage that sucks and compresses the refrigerant compressed by the low-stage compression mechanism. A plurality of compression mechanisms including at least two stages including a side compression mechanism (6),
A multistage compressor (2, 2A, 2B, 2C, 2D, 2E, 2F, 2G) in which the refrigerant extracted from the refrigeration cycle is injected into the low stage compression mechanism.   The closed housing is formed separately from an internal suction pressure space that accommodates the low-stage compression mechanism and the high-stage compression mechanism, and is connected to the low-stage compression mechanism and the high-stage compression mechanism; The multistage compressor according to claim 1, further comprising an intermediate pressure chamber (5) configured to be able to pass a refrigerant discharged from a side compression mechanism and sucked into the high stage compression mechanism.   In the sealed housing, the refrigerant extracted from the refrigeration cycle is injected into an internal intermediate pressure space (SP) through which the refrigerant discharged from the low-stage compression mechanism and sucked into the high-stage compression mechanism passes. The multistage compressor according to claim 1. The multistage compressor according to claim 2, wherein in the sealed housing, the refrigerant extracted from the refrigeration cycle is injected into the intermediate pressure chamber.   The multistage compressor according to any one of claims 1 to 4, wherein a refrigerant extracted from the refrigeration cycle is injected into the high stage side compression mechanism.   The said compression mechanism in which the said refrigerant | coolant is injected is provided with the non-return valve (72, 92) which prevents the reverse flow of the refrigerant | coolant to the injection piping (21, 25) for injecting the said refrigerant | coolant into the said compression mechanism. The multistage compressor of any one of thru | or 5.   The multistage compressor according to claim 6, wherein the check valve is provided in the compression mechanism.   The multistage compressor according to any one of claims 1 to 7, wherein at least one of the plurality of compression mechanisms is a scroll type compression mechanism.   The multistage compressor according to claim 8, wherein the scroll compression mechanism has a compression chamber (4a, 6a) on one side of the substrate.   The multistage compressor according to claim 8, wherein the scroll compression mechanism has compression chambers on both sides of the substrate. Power generation means (31) housed in the hermetic housing and serving as a drive source for the plurality of compression mechanisms,
9. The multi-stage according to claim 8, wherein the low-stage compression mechanism is arranged on one side of the power generation means and the high-stage compression mechanism is arranged on the other side of the power generation means in the sealed housing. Compressor. The multistage compressor according to any one of claims 8 to 11, comprising a relief valve (68, 88) provided in the scroll compression mechanism.   The multistage compressor according to any one of claims 8 to 12, wherein the number of turns of the scroll compression mechanism is one or less.   The multistage compressor according to any one of claims 1 to 13, wherein the refrigerant is carbon dioxide.

Images