JP6102172B2 - Rotary compressor - Google Patents

Description

  The present invention relates to a rotary compressor provided with an eccentric rotation type compression mechanism in which a plurality of cylinder chambers are formed between a piston and a cylinder to perform multistage compression.

  Conventionally, a rotary compressor in which a plurality of cylinder chambers are formed in a compression mechanism by arranging an annular piston inside an annular cylinder chamber of a cylinder has been proposed (see, for example, Patent Document 1). . In the compression mechanism of the compressor of Patent Document 1, annular pistons and cylinders are arranged on both sides of the middle plate, and four cylinder chambers are formed on both sides of the middle plate. And this rotary compressor is comprised so that a refrigerant | coolant may be compressed 4 steps | paragraphs in the refrigerant circuit of refrigeration apparatuses, such as an air conditioning apparatus.

JP 2011-196270 A

  In the compressor of Patent Document 1, the discharge pressure at the final stage is determined by the volume ratio of the compressor, and the system (refrigerant circuit) cannot be controlled to an arbitrary high pressure, resulting in an inefficient operation cycle. In particular, as shown in FIGS. 11A and 11B, when the volume of each stage compression mechanism is determined based on the cooling operation of multistage compression cooling in which an intermediate cooler is provided between each stage, FIG. During the heating operation shown in (A) and (B), intermediate cooling is not performed, and the refrigerant is compressed in the preceding stage until the final stage volume is reached, so that the high-pressure pressure increases excessively. That is, even if the fourth-stage discharge pressure is set to the high pressure of the system, as shown in the PV diagram of FIG. 12B, until the suction volume Vc4 of the fourth-stage compression mechanism is reached in the third-stage compression mechanism. The compression is performed and the high pressure is abnormally increased, and the cycle efficiency (performance) is significantly reduced.

  On the other hand, a mechanism that uses a check valve to relieve the refrigerant from the lower-stage discharge space where the pressure is relatively high to the upper-stage discharge space where the pressure is relatively low can be considered. In the above multistage compressor, it is structurally difficult to install relief valves in all stages. Further, even if relief valves are not provided in all stages of the multistage compression, even if they are provided in a plurality of stages, the cost increases due to the increase in the number of parts and the increase in the number of processing parts due to the installation of the relief valves. Furthermore, if the relief valves are installed in a plurality of stages, the leakage loss is greatly increased, and the compressor performance may be significantly deteriorated.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a rotation having an eccentric rotation type compression mechanism in which a plurality of cylinder chambers are formed between a piston and a cylinder to perform multistage compression. In the compressor, it is possible to prevent a reduction in cycle efficiency due to an abnormal increase in high pressure while preventing a complicated configuration and an increase in the number of parts.

1st invention is a refrigerant circuit which performs a refrigerating cycle, supplies a refrigerant | coolant from a low stage side to a high stage side via an intermediate cooler at the time of cooling operation, performs multistage compression, and does not go through an intermediate cooler at the time of heating operation A compression mechanism (40) that performs multi-stage compression by directly supplying refrigerant from the low-stage side to the high-stage side includes the cylinder (21, 31) and the cylinder (21, 31). And a plurality of cylinder chambers (23a to 23d, 33a to 33d) formed between the piston (22, 32) and the cylinder (21, 31) and the piston (22, 32). And a rotary compressor configured to compress the working fluid in three or more stages.

  The rotary compressor has a relief mechanism (100) communicating with the discharge space (84a) of the highest stage compression mechanism in the discharge space (83a) of the lower stage compression mechanism, which is lower than the highest stage compression mechanism. ) Is provided.

  Here, when the high pressure of the system falls below the discharge pressure of the low-stage compression mechanism, which is lower than the highest-stage compression mechanism, the pressure in the discharge space (84a) of the highest-stage compression mechanism is almost equal to the high pressure of the system. Therefore, the pressure in the discharge space (83a) of the low-stage compression mechanism tends to be higher than the pressure in the discharge space (84a) of the highest-stage compression mechanism. In the first aspect of the invention, the relief mechanism (100) operates to discharge the discharge space (84a) of the highest-stage compression mechanism having a relatively low pressure from the discharge space (83a) of the low-stage compression mechanism having a relatively high pressure. ) To the working fluid. As a result, the pressure in the discharge space (83a) of the low-stage compression mechanism is reduced to equalize the high pressure of the system.

  According to a second invention, in the first invention, the compression mechanism (40) is a four-stage compression mechanism, the relief mechanism (100) is provided in the discharge space (83a) of the third-stage compression mechanism, It is characterized by being configured to communicate with the discharge space (84a) of the stage compression mechanism.

  When the high pressure of the system falls below the discharge pressure of the third stage compression mechanism, which is lower than the fourth stage compression mechanism, the pressure in the discharge space (84a) of the fourth stage compression mechanism is almost equal to the high pressure of the system. Therefore, the pressure in the discharge space (83a) of the third-stage compression mechanism becomes higher than the pressure in the discharge space (84a) of the fourth-stage compression mechanism. In the second aspect of the invention, the relief mechanism (100) operates and the discharge space (83a) of the third-stage compression mechanism, which has a relatively high pressure, discharges the discharge space of the fourth-stage compression mechanism, which has a relatively low pressure. The working fluid flows to (84a). As a result, the pressure in the discharge space (83a) of the third-stage compression mechanism is reduced to equalize the high pressure of the system.

The third invention includes a cylinder (21, 31), a piston (22, 32) configured to be eccentrically rotatable with respect to the cylinder (21, 31), a cylinder (21, 31) and a piston (22, 31). 32) a rotary compressor including a plurality of cylinder chambers (23a to 23d, 33a to 33d) formed between them and a compression mechanism (40) for compressing the working fluid in three or more stages. As a premise, a relief mechanism (100) communicating with the discharge space (84a) of the highest stage compression mechanism is provided in the discharge space (83a) of the lower stage compression mechanism on the lower stage side than the highest stage compression mechanism, The compression mechanism (40) is a four-stage compression mechanism,
The relief mechanism (100) is provided in the discharge space (83a) of the third-stage compression mechanism, and is configured to communicate with the discharge space (84a) of the fourth-stage compression mechanism. It is characterized in that the cylinder capacity of the third stage compression mechanism is equal.

  In the third aspect of the invention, since the cylinder volume of the second stage compression mechanism is equal to the cylinder volume of the third stage compression mechanism, the fluid discharged from the second stage compression mechanism can be sucked by the third stage compression mechanism. Therefore, the fluid discharged from the second-stage compression mechanism can always be processed by the third-stage compression mechanism. Then, due to the cooling effect by the intermediate cooling or the injection operation, the suction refrigerant density of the third stage compression mechanism becomes larger than the discharge refrigerant density of the second stage compression mechanism, and the second stage discharge volume and the third stage suction volume are moderate. To balance.

  According to a fourth invention, in any one of the first to third inventions, the compression mechanism (40) is a middle plate (25) and the middle plate (25) is disposed above the middle plate (25). 1 compression mechanism part (20) and the 2nd compression mechanism part (30) arrange | positioned below, The said relief mechanism (100) is provided in the 1st compression mechanism part (20), It is characterized by the above-mentioned. Yes.

  In the fourth aspect of the invention, for example, the discharge space (83a) of the third-stage compression mechanism and the discharge space (84a) of the fourth-stage compression mechanism are formed in the first compression mechanism portion (20) above the middle plate (25). In this case, the relief mechanism (100) is also provided in the first compression mechanism section (20). And when the high pressure of the system becomes lower than the discharge pressure of the third stage compression mechanism, a configuration is adopted in which the discharge fluid of the third stage compression mechanism is discharged upward through the discharge space (84a) of the fourth stage compression mechanism. can do.

  According to the present invention, in an operating condition where the high pressure of the system is lower than the discharge pressure of the low-stage compression mechanism, which is lower than the highest-stage compression mechanism, the relief mechanism (100) operates, The working fluid flows from the discharge space (83a) of the low-stage compression mechanism having a high pressure to the discharge space (84a) of the highest-stage compression mechanism having a relatively low pressure. ) Is equalized to the high pressure of the system. Therefore, since it can suppress that the discharge pressure of a compressor raises too much, it can prevent that the efficiency of a refrigerating cycle falls. Further, since the relief mechanism (100) may be provided in one place in the low-stage compression mechanism, it is possible to suppress the complexity of the configuration, and it is possible to suppress the reduction in the efficiency of the compressor by suppressing the leakage loss. .

  According to the second aspect of the present invention, in the compressor provided with the compression mechanism (40) for performing the four-stage compression, the relief mechanism (100) is simply provided in the discharge space (83a) of the third-stage compression mechanism. Since it is possible to prevent the discharge pressure of the compressor from excessively increasing when the high pressure is lowered, it is possible to prevent the cycle efficiency from being lowered with a simple configuration and to suppress leakage loss.

  According to the third aspect, since the cylinder volume of the second stage compression mechanism and the cylinder volume of the third stage compression mechanism are made equal, the second stage discharge volume and the third stage suction volume are appropriately balanced. Therefore, the discharge pressure of the second stage compression mechanism does not increase too much. Therefore, in the second aspect of the present invention, the discharge pressure of the compressor is excessively increased only by providing the relief mechanism (100) in the third stage compression mechanism without providing the relief mechanism in the second stage compression mechanism. Can be surely prevented.

  According to the fourth aspect, since the relief mechanism (100) is provided in the first compression mechanism (20) on the upper side of the middle plate (25), the discharge fluid is discharged upward from the compression mechanism (40). A configuration can be employed. An oil sump for storing lubricating oil is generally provided at the bottom of the compressor casing, and the third stage compression mechanism is provided in the second compression mechanism section (30) below the middle plate (25) so that the fluid is directed downward. In the case of discharging into the compression mechanism (40), it may be necessary to provide a discharge cover at the bottom of the compression mechanism (40) or to provide a fluid discharge passage in the compression mechanism (40). According to the present invention, it is possible to prevent the configuration from becoming complicated.

FIG. 1 is a longitudinal sectional view of a rotary compressor according to the first embodiment. FIG. 2 is an enlarged view around the compression mechanism in FIG. 3A is a cross-sectional view of the compression mechanism section, and FIG. 3B is another cross-sectional view of the compression mechanism section. FIG. 4 is a perspective view of the blade. FIG. 5 is a partially enlarged view of the compression mechanism section. FIG. 6 is an operation state diagram of the compression mechanism section. FIG. 7 is an operation state diagram of the compression mechanism section. FIG. 8 is a cross-sectional view of the main body of the middle plate. FIG. 9 is a schematic diagram showing the relationship between the pressing force of the piston against the cylinder and the separation force in the compressor of the comparative example (conventional example), and FIG. 9A shows a state where an appropriate pressing force is obtained. 9 (B) shows a state where the pressing force is insufficient. FIG. 10 is a schematic diagram showing the relationship between the pressing force of the piston against the cylinder and the separation force in the compressor of the present embodiment. FIG. 11A is a ph diagram illustrating a refrigeration cycle during cooling operation, and FIG. 11B is a pv diagram. FIG. 12A is a ph diagram showing a refrigeration cycle during cooling operation, and FIG. 12B is a p-v diagram. FIG. 13 is a cross-sectional view illustrating a compression mechanism of the rotary compressor according to the first modification of the first embodiment. FIG. 14 is a cross-sectional view illustrating a compression mechanism of the rotary compressor according to the second modification of the first embodiment. FIG. 15 is a cross-sectional view illustrating a compression mechanism of the rotary compressor according to the second embodiment.

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

Embodiment 1 of the Invention
A first embodiment of the present invention will be described.

  The compressor (1) according to the first embodiment is a rotary compressor, and, as shown in FIG. 1, two compression mechanism portions (a first compression mechanism portion (20) and a second compression mechanism) are provided in a casing (10). The compression mechanism (40) in which the mechanism portion (30) is stacked in the axial direction of the drive shaft (53) and the electric motor (50) as the drive mechanism are housed, and is configured to be completely sealed. This compressor (1) is used, for example, in a refrigerant circuit of an air conditioner to compress refrigerant (working fluid) sucked from an evaporator and discharge it to a condenser. A middle plate (25) described later is disposed between the first compression mechanism (20) and the second compression mechanism (30).

  The casing (10) includes a cylindrical body (11), an upper end plate (12) fixed to the upper end of the body (11), and a lower part fixed to the lower end of the body (11). End plate (13). In order to guide the refrigerant to the cylinder chambers (23a,..., 23d, 33a,..., 33d) of the first compression mechanism section (20) and the second compression mechanism section (30), the details of which will be described later. Suction pipe (60, 61, 62, 63) and a discharge pipe (64, 65, 66) for discharging the refrigerant compressed in the cylinder chamber (23b, 23c, 23d, 33b, 33c, 33d) It is provided through. The upper end plate (12) is also provided with a discharge pipe (67) for discharging the refrigerant compressed in the cylinder chambers (23a, 33a).

  The electric motor (50) is disposed near the upper end plate (12) in the casing (10). The electric motor (50) includes a stator (51), a rotor (52), and a drive shaft (53). The stator (51) is fixed to the inner peripheral surface of the body (11) of the casing (10). On the other hand, the drive shaft (53) is connected to the rotor (52) so as to rotate integrally.

  The drive shaft (53) extends downward from the rotor (52), and a first eccentric part (53a) and a second eccentric part (53b) are formed in the lower part. The first eccentric portion (53a) is formed to have a larger diameter than the main shaft portion above the first eccentric portion (53a), and is eccentric by a predetermined amount from the axis of the drive shaft (53). On the other hand, the second eccentric portion (53b) is formed to have the same diameter as the first eccentric portion (53a), and is eccentric from the axis of the drive shaft (53) by the same amount as the first eccentric portion (53a). The first eccentric portion (53a) and the second eccentric portion (53b) are 180 ° out of phase with each other about the axis of the drive shaft (53).

  The first compression mechanism portion (20) and the second compression mechanism portion (30) are disposed below the electric motor (50) in the casing (10). The first compression mechanism section (20) and the second compression mechanism section (30) are stacked in two upper and lower stages, and are configured between the front head (14) and the rear head (17) fixed to the casing (10). Has been. The first compression mechanism (20) is disposed on the electric motor (50) side (upper side in FIG. 1), and the second compression mechanism (30) is disposed on the bottom side (lower side in FIG. 1) of the casing (10). ing. A muffler member (27) for forming a muffler space (27a) between the front head (14) and the upper surface of the front head (14) is attached to the upper side of the front head (14).

  As shown in FIGS. 2 to 5, the first compression mechanism (20) includes a first cylinder (21) fixed to the inner peripheral surface of the body (11) of the casing (10), and a drive shaft (53 ) Of the first piston (22) attached to the first eccentric portion (53a) and rotating eccentrically with respect to the first cylinder (21), and the first cylinder (21) and the first piston (22) A first blade (4) that divides four cylinder chambers (23a, 23b, 23c, 23d) formed between them into a high pressure chamber (23aH, 23bH, 23cH, 23dH) and a low pressure chamber (23aL, 23bL, 23cL, 23dL) 24) and.

  The first cylinder (21) includes a cylindrical cylinder body (21c) that forms a cylinder space (S1) therein and opens vertically, and a head that closes the upper opening of the cylinder body (21c). A front head (14) as a part, a plurality of cylinder parts (21a, 21b, 21c) formed in an annular shape and concentrically with the rotating shaft of the drive shaft (53), and the cylinder body part (21c) And the middle plate (25) disposed in the lower opening.

  The front head (14) includes a cylinder space side front head (15) as a cylinder space side head portion, and a bearing portion side front head (16) as a bearing portion side head portion.

  The cylinder space-side front head (15) includes a closing portion (15a) formed in a disc shape covering the upper opening of the cylinder body (21c). The cylinder space side front head (15) is formed integrally with the cylinder body (21c). A through hole (15b) through which the drive shaft (53) is inserted is formed in the central portion of the blocking portion (15a). The through hole (15b) is formed to have a slightly larger diameter than the drive shaft (53).

  The bearing portion-side front head (16) is formed separately from the cylinder space-side front head (15), and is disposed above the cylinder space-side front head (15). The bearing portion-side front head (16) includes a disk-shaped laminated portion (16a) that is superimposed on the upper surface of the cylinder space-side front head (15), and a bearing portion (16b) that is formed integrally with the laminated portion (16a). ). A through hole (16c) through which the drive shaft (53) is inserted is formed at the center of the stacked portion (16a). The bearing portion (16b) is formed in a cylindrical shape extending upward from the opening end portion of the through hole (16c) of the laminated portion (16a). A cylindrical bearing metal (16d) for rotatably supporting the drive shaft (53) is inserted and fixed on the inner peripheral surface of the bearing portion (16b).

  The plurality of cylinder portions (21a, 21b, 21c) are formed integrally with the cylinder space front head (15) on the lower surface of the cylinder space front head (15). The plurality of cylinder parts include an annular inner cylinder part (21a) formed at the innermost side, an annular outer cylinder part (21b) formed radially outward from the inner cylinder part (21a), The cylindrical outermost cylinder part (21c) is located outside the outer cylinder part (21b) and extends downward from the outer peripheral part of the outer cylinder part (21b). The inner cylinder part (21a) is partly cut off from the ring (see FIG. 3A). A slide groove (21g) is formed at a parting position of the inner cylinder part (21a). The outermost cylinder part (21c) is composed of the cylinder body part (21c).

  The middle plate (25) is formed by two members arranged in the axial direction of the drive shaft (53). Specifically, the middle plate (25) has a slightly thick disc-shaped main body (25a) covering the lower opening of the cylinder main body (21c) and a lower surface of the main body (25a). And a disc-shaped lid (25b) to be stacked. A through hole (25c) through which the drive shaft (53) passes is formed at the center of the middle plate (25). The through hole (25c) is a hole having a slightly larger inner diameter than the diameters of the first eccentric portion (53a) and the second eccentric portion (53b) of the drive shaft (53). The middle plate (25) also constitutes a part of the second compression mechanism part (30).

  The first piston (22) is accommodated in a cylinder chamber (S1) formed inside a cylindrical cylinder body (21c). The first piston (22) is fitted to the first eccentric part (53a) and is located concentrically with the first eccentric part (53a), and the inner piston part (22a) An outer piston portion (22b) concentric with the inner piston portion (22a) is connected to the outer peripheral side and a lower end portion of the two piston portions (22a, 22b), and an outer peripheral surface is the inner piston portion (22a). And an outer piston part (22b) and a piston side end plate part (22c) located concentrically. The inner piston part (22a) is arranged inside the inner cylinder part (21a), and the outer piston part (22b) is arranged between the inner cylinder part (21a) and the outer cylinder part (21b), The end plate part (22c) is disposed inside the outermost cylinder part (21c). The inner piston portion (22a) has a notch (n1) formed on the outer peripheral surface, and the outer piston portion (22b) is partly cut off from the ring (see FIG. 3A). Further, a notch (n2) is formed in the outer peripheral portion of the piston side end plate portion (22c) (see FIG. 3B).

  As described above, the first piston (22) disposed in the cylinder space (S1) forms a plurality of cylinder chambers with the first cylinder (21). Specifically, an innermost cylinder chamber (23a) is formed between the inner piston part (22a) and the inner cylinder part (21a), and between the outer piston part (22b) and the inner cylinder part (21a). Is formed with an inner cylinder chamber (23b), an outer cylinder chamber (23c) is formed between the outer piston portion (22b) and the outer cylinder portion (21b), and the piston side end plate portion (22c) and the outermost portion An outermost cylinder chamber (23d) is formed between the cylinder portion (21c). That is, in the first compression mechanism (20), the innermost cylinder chamber (23a), the inner cylinder chamber (23b), and the outer cylinder chamber (23c) are arranged in order from the radially inner side to the radially outer side. A chamber (23d) is formed.

  Thus, the 1st compression mechanism part (20) is constituted so that it may have four cylinder chambers (23a, 23b, 23c, 23d).

  The second compression mechanism section (30) is disposed below the first compression mechanism section (20). As shown in FIGS. 2 to 5, the second compression mechanism section (30) includes a second cylinder (31) fixed to the inner peripheral surface of the body section (11) of the casing (10), and a drive shaft (53 ) Of the second piston (32) attached to the second eccentric portion (53b) and rotating eccentrically with respect to the second cylinder (31), and the second cylinder (31) and the second piston (32) A second blade (4) that divides four cylinder chambers (33a, 33b, 33c, 33d) formed between them into a high pressure chamber (33aH, 33bH, 33cH, 33dH) and a low pressure chamber (33aL, 33bL, 33cL, 33dL) 34).

  The second cylinder (31) forms a cylinder space (S2) therein and closes the cylindrical cylinder body (31c) that opens in the vertical direction and the lower opening of the cylinder body (31c). A rear head (17) as a head portion, a plurality of cylinder portions (31a, 31b, 31c) which are formed in an annular shape and concentrically with the rotation shaft of the drive shaft (53), and the cylinder body portion (31c) A middle plate (25) disposed in the upper opening.

  The rear head (17) includes a cylinder space side rear head (18) as a cylinder space side head portion and a bearing portion side rear head (19) as a bearing portion side head portion.

  The cylinder space side rear head (18) includes a closing portion (18a) formed in a disk shape covering the lower opening of the cylinder body (31c). The cylinder space side rear head (18) is formed integrally with the cylinder body (31c). A through hole (18b) through which the drive shaft (53) is inserted is formed in the central portion of the blocking portion (18a). The through hole (18b) is formed to have a slightly larger diameter than the drive shaft (53).

  The bearing portion side rear head (19) is formed separately from the cylinder space side rear head (18), and is disposed below the cylinder space side rear head (18). The bearing portion side rear head (19) includes a disk-shaped laminated portion (19a) that is stacked on the lower surface of the cylinder space side rear head (18), and a bearing portion (19b) that is formed integrally with the laminated portion (19a). It has. A through hole (19c) through which the drive shaft (53) is inserted is formed at the center of the stacked portion (19a). The bearing portion (19b) is formed in a cylindrical shape extending downward from the opening end portion of the through hole (19c) of the laminated portion (19a). A cylindrical bearing metal (19d) for rotatably supporting the drive shaft (53) is inserted and fixed on the inner peripheral surface of the bearing portion (19b).

  The plurality of cylinder portions (31a, 31b, 31c) are formed integrally with the cylinder space side rear head (18) on the upper surface of the cylinder space side rear head (18). The plurality of cylinder parts include an annular inner cylinder part (31a) formed at the innermost side, an annular outer cylinder part (31b) formed radially outward from the inner cylinder part (31a), The cylindrical outermost cylinder part (31c) is located outside the outer cylinder part (31b) and extends upward from the outer peripheral part of the outer cylinder part (31b). The inner cylinder part (31a) is partly cut off from the ring (see FIG. 3A). A slide groove (31g) is formed at a parting position of the inner cylinder part (31a). The outermost cylinder part (31c) is composed of the cylinder body part (31c).

  The second piston (32) is accommodated in a cylinder chamber (S2) formed inside the cylindrical cylinder body (31c). The second piston (32) is fitted to the second eccentric part (53b) and is located concentrically with the second eccentric part (53b), and the inner piston part (32a) The outer piston part (32b) concentrically positioned with the inner piston part (32a) is connected to the outer peripheral side and the upper ends of the two piston parts (32a, 32b) and the outer peripheral surface is the inner piston part (32a). And an outer piston part (32b) and a piston side end plate part (32c) positioned concentrically. The inner piston part (32a) is arranged inside the inner cylinder part (31a), and the outer piston part (32b) is arranged between the inner cylinder part (31a) and the outer cylinder part (31b), The end plate part (32c) is disposed inside the outermost cylinder part (31c). The inner piston part (32a) has a notch part (n1) formed on the outer peripheral surface, and the outer piston part (32b) is partly cut off from a ring (see FIG. 3A). Further, a notch (n2) is formed in the outer peripheral portion of the piston side end plate portion (32c) (see FIG. 3B).

  As described above, the second piston (32) disposed in the cylinder space (S2) forms a plurality of cylinder chambers with the second cylinder (31). Specifically, an innermost cylinder chamber (33a) is formed between the inner piston part (32a) and the inner cylinder part (31a), and between the outer piston part (32b) and the inner cylinder part (31a). Is formed with an inner cylinder chamber (33b), an outer cylinder chamber (33c) is formed between the outer piston part (32b) and the outer cylinder part (31b), and the piston side end plate part (32c) and the outermost part. An outermost cylinder chamber (33d) is formed between the cylinder portion (31c). That is, in the second compression mechanism (30), the innermost cylinder chamber (33a), the inner cylinder chamber (33b), and the outer cylinder chamber (33c) are arranged in order from the radially inner side to the radially outer side. A chamber (33d) is formed.

  Thus, the second compression mechanism section (30) is configured to have four cylinder chambers (33a, 33b, 33c, 33d).

  The first compression mechanism part (20) and the second compression mechanism part (30) are eccentric with respect to the cylinders (first cylinder (21) and second cylinder (31)) and the cylinders (21, 31). A piston (first piston (21) and second piston (22)) having a mirror plate portion (piston side end plate portion (22c, 32c)) facing the middle plate (25) and configured to be rotatable, and a cylinder A plurality of cylinder chambers (23a, 23b, 23c, formed between the (first cylinder (21) and second cylinder (31)) and the piston (first piston (21) and second piston (22)). 23d) (33a, 33b, 33c, 33d).

  Next, the internal structure of the first and second compression mechanism parts (20, 30) will be described in detail. The first and second compression mechanism parts (20, 30) have first and second pistons (22, 32). ) And the corresponding cylinder (21, 31) in the axial direction are substantially identical in configuration, so the first compression mechanism (20) will be described as a representative example. To do.

  As shown in FIGS. 4 and 5, the first blade (24) has a plate-like long part (24a) and a short part (24b) having a thickness and a pair of swings having a substantially semicircular cross section. And a bush portion (24c). These three parts (24a, 24b, 24c) are integrally formed.

  The long portion (24a) is disposed so as to extend in the radial direction between the closed portion (15a) of the cylinder space-side head portion (15) and the piston-side end plate portion (22c). The long portion (24a) includes an inner blade portion (B1) constituting a radially inner portion of the long portion (24a) and an outer first portion constituting a portion outside the inner blade portion (B1). It consists of a blade part (B2). The inner blade portion (B1) is inserted into the slide groove (21g) formed in the dividing portion of the inner cylinder portion (21a) so as to be slidable in the radial direction, and is the outer end portion of the outer first blade portion (B2). Are accommodated in a groove (slide groove) (21f) formed in the outer cylinder part (21b) so as to be slidable in the radial direction. The inner blade portion (B1) divides the innermost cylinder chamber (23a) and the inner cylinder chamber (23b) into a suction side and a discharge side, respectively, and the outer first blade portion (B2) separates the outer cylinder chamber ( 23c) is divided into a suction side and a discharge side. The inner end portion of the inner blade portion (B1) is opposed to the notch portion (n1) of the inner piston portion (22a) with a micron-order fine gap therebetween (see FIG. 5).

  The short part (24b) is disposed so as to extend in the radial direction between the long part (24a) and the middle plate (25). The short part (24b) is composed of an outer second blade part (B3). The radially outer portion of the short portion (24b) is accommodated in a groove (slide groove) (21f) formed in the outermost cylinder portion (21c) so as to be slidable in the radial direction. The shortest portion (24b) divides an outermost cylinder chamber (23d), which will be described later, into a suction side and a discharge side. The inner end of the short part (24b) is opposed to the notch part (n2) of the piston side end plate part (22c) with a micron-order fine gap (see FIG. 5).

  The pair of swinging bush portions (24c) is formed so as to bulge on both sides of the long portion (24a) in the vicinity of the central portion in the longitudinal direction of the long portion (24a). The outer peripheral surfaces of the pair of swing bush portions (24c) constitute a part of the outer peripheral surface of a cylinder having a predetermined radius. The pair of swinging bush portions (24c) is swingably accommodated in bush grooves (C1, C2) formed at the parting points of the outer piston portion (22b). The pair of swing bush portions (24c) is configured such that the outer piston portion (22b) swings with respect to the first blade (24).

  In FIG. 5, the notch (n1) constitutes a first swing allowing surface that allows the relative swinging motion of the inner blade portion (B1) with the swing bushing portion (24c) as the center. The first rocking permissible surface (n1) is based on an arc shape having a diameter slightly larger than the locus of the relative rocking motion of the inner blade part (B1) around the rocking bush part (24c). A fine gap is formed between the locus drawn by the tip of the inner blade portion (B1) when the inner blade portion (B1) swings and the first swing allowable surface (n1). In FIG. 5, the fine gap is exaggerated.

  Further, the notch (n2) constitutes a second swing allowing surface that allows the relative swing operation of the outer second blade portion (B3) with the swing bush portion (24c) as a center. The second rocking permissible surface (n2) is an arc shape having a slightly smaller diameter than the locus of the relative rocking movement of the outer second blade part (B3) centering on the rocking bush part (24c). So that a fine gap is formed between the locus drawn by the tip of the outer second blade portion (B3) when the outer second blade portion (B3) swings and the second swing allowable surface (n2). It has become. In FIG. 5, the fine gap is exaggerated.

  With the configuration as described above, the first piston (22) has the center point of the pair of swing bush portions (24c) with respect to the first blade (24) as the first eccentric portion (53a) rotates eccentrically. Oscillates around the center of the oscillating center, and advances and retracts in the same direction as the first blade (24) slides in the longitudinal direction with respect to the groove (21f) and the slide groove (21g) of the inner cylinder part (21a). To do.

  The inner piston portion (22a, 32a) and the inner cylinder portion (21a, 31a) of the first compression mechanism portion (20) and the second compression mechanism portion (30) are arranged on the outer peripheral surface and the inner side of the inner piston portion (22a, 32a). A state where the inner peripheral surface of the cylinder part (21a, 31a) is substantially in contact at one point (first contact) (strictly, there is a micron-order gap, but refrigerant leakage in the gap does not cause a problem) ), The outer peripheral surface of the inner cylinder portion (21a, 31a) and the inner peripheral surface of the outer piston portion (22b, 32b) are substantially at one point (second contact) at a position 180 degrees out of phase with the contact. The outer piston part (22b, 32b) and the outer cylinder part (21b, 31b) have an outer peripheral surface at a position that is 180 degrees out of phase with the contact (the same position as the first contact). It is substantially in contact at one point (third contact), and the outer peripheral surface of the piston side end plate part (22c, 32c) and the outermost cylinder part (21c, 31c) It faces and is in contact with the substantially at one point (4 contact).

  In the above configuration, when the drive shaft (53) rotates, the first piston (22) swings about the center point of the swing bush portion (24c), and together with the first blade (24), the first piston (22) swings. Advances and retracts in the longitudinal direction of one blade (24). Further, when the drive shaft (53) rotates, the second piston (32) swings about the center point of the swinging bush portion (34c), and the second blade (34) together with the second blade (34). 34) Move forward and backward in the longitudinal direction.

  By the above operation, the contacts (first contact to fourth contact) of the first piston (22) and the first cylinder (21) are changed to FIGS. 6 (A) to (D) and FIGS. 7 (A) to (D), respectively. Move in order. On the other hand, each contact (1st contact-4th contact) of a 2nd piston (32) and a 2nd cylinder (31) drives with respect to a corresponding contact of a 1st piston (22) and a 1st cylinder (21). It is shifted by 180 ° around the axis of the shaft (53). That is, when viewed from above the drive shaft (53), when the operating state of the first compression mechanism (20) is as shown in FIGS. 6 (A) and 7 (A), the operating state of the second compression mechanism (30). 6C and FIG. 7C.

  In the present embodiment, the compression mechanism (40) is configured as a four-stage compression mechanism that compresses the refrigerant into four stages in the eight cylinder chambers (23a, ..., 23d, 33a, ..., 33d).

  Specifically, the cylinder chamber of the first stage compression mechanism is formed by the outermost cylinder chambers (23d, 33d) of the first compression mechanism portion (20) and the second compression mechanism portion (30). Further, a cylinder chamber of the second stage compression mechanism is formed by the outer cylinder chamber (33c) and the inner cylinder chamber (33b) of the second compression mechanism section (30), and the outer cylinder chamber of the first compression mechanism section (20). (23c) and the inner cylinder chamber (23b) form a cylinder chamber of the third-stage compression mechanism. Furthermore, the cylinder chamber of the fourth stage compression mechanism is formed by the innermost cylinder chambers (23a, 33a) of the first compression mechanism portion (20) and the second compression mechanism portion (30). In the present embodiment, the axial length of the outer piston portions (22, 32) of the first and second compression mechanisms (20, 30) and the corresponding axial length of the cylinders (21, 31) are the same. Since they are the same, the cylinder volume of the second stage compression mechanism and the cylinder volume of the third stage compression mechanism are substantially equal.

  Thus, the compressor (1) of the first embodiment includes a cylinder (21, 31) having an annular cylinder space and an annular piston (22) arranged eccentrically with respect to the cylinder (21, 31). 32), and a plurality of cylinder chambers (23a, ..., 23d, 33a, ..., 33d) are formed between the cylinders (21, 31) and the pistons (22, 32), and A rotary compressor having a compression mechanism (20, 30) in which one suction port and one discharge port communicating with each cylinder chamber (23a, ..., 23d, 33a, ..., 33d) are formed, Four cylinder chambers (23a, ..., 23d, 33a, ..., 33d) are formed between a pair of cylinders (21,31) and pistons (22,32), and these cylinder chambers (23a, ..., 23d) , 33a, ..., 33d), the cylinder chamber (23d, 33d) of the first stage compression mechanism that compresses the low-pressure refrigerant in the first stage, and the second stage compression mechanism that compresses the discharged refrigerant of the first stage compression mechanism in the second stage. of Linda chamber (33c, 33b), cylinder chamber (23c, 23b) of third stage compression mechanism for third stage compression of refrigerant discharged from second stage compression mechanism, and fourth stage compression of discharge refrigerant of third stage compression mechanism The cylinder chamber (23a, 33a) of the fourth stage compression mechanism is formed. The refrigerant circuit is between the first stage compression mechanism and the second stage compression mechanism, between the second stage compression mechanism and the third stage compression mechanism, and between the third stage compression mechanism and the fourth stage compression mechanism. It is good to comprise so that a refrigerant can be cooled with a cooling mechanism.

  The compression mechanism (40) includes first to fourth suction flow paths (not shown) for guiding refrigerant from the suction pipes (60 to 63) to the cylinder chambers (23a, ..., 23d, 33a, ..., 33d). 71-74) are formed. The first to fourth suction flow paths (71 to 74) constitute the suction flow paths of the first-stage compression mechanism to the fourth-stage compression mechanism, respectively. These suction passages (71 to 74) do not cross each other, and other parts formed in the compression mechanism (40) (each blade (24, 34), discharge valve (88), etc.) Is formed in the compression mechanism (40) so as not to interfere.

  The first suction channel (71) has an inflow end connected to the suction pipe (62), and an outflow end constituted by the suction ports (P1, P1) is the outermost cylinder chamber of the first compression mechanism (20) ( 23d) and the outermost cylinder chamber (33d) of the second compression mechanism (30). The second suction flow path (72) has an inflow end connected to the suction pipe (63), and an outflow end constituted by the suction port (P2) at the inner cylinder chamber (33b) of the second compression mechanism (30). Connected to the outer cylinder chamber (33c). The third suction flow path (73) has an inflow end connected to the suction pipe (60), and an outflow end constituted by the suction port (P2) at the inner cylinder chamber (23b) of the first compression mechanism (20). Connected to the outer cylinder chamber (23c). The fourth suction flow path (74), which is the suction part of the fourth stage compression mechanism, has an inflow end connected to the suction pipe (61), and an outflow end constituted by the suction ports (P3, P3) as the first compression mechanism. The innermost cylinder chamber (23a) of the part (20) and the innermost cylinder chamber (33a) of the second compression mechanism part (30) are connected.

  The fourth suction flow path (74) includes a suction pipe side flow path (74a) extending vertically in the compression mechanism (40) and a suction port side flow path (74b) extending horizontally in the compression mechanism (40). ) And are formed. The suction port side flow path (74b) includes a facing surface of the cylinder space side front head (15) in the stacked portion (16a) of the bearing portion side front head (16) and a stacked portion of the bearing portion side rear head (19) ( It can be easily formed by notching the facing surface of the cylinder space side rear head (18) in 19a) into a groove shape.

  The compression mechanism (40) includes first to fourth refrigerants for guiding the refrigerant compressed in the cylinder chambers (23a,..., 23d, 33a,..., 33d) to the outside of the compression mechanism (40). Discharge flow paths (81 to 84) are formed. The first to fourth discharge flow paths (81 to 84) constitute discharge flow paths of the first-stage compression mechanism to the fourth-stage compression mechanism, respectively. These discharge flow paths (81 to 84) do not cross each other and other parts formed in the compression mechanism (40) (each blade (24, 34), discharge valve (88), etc.) Is formed in the compression mechanism (40) so as not to interfere.

  The first discharge flow path (81), which is the discharge portion of the first stage compression mechanism, has an inflow end constituted by discharge ports (P11, P11) at the outermost cylinder chamber (23d) of the first compression mechanism portion (20). The second compression mechanism (30) is connected to the outermost cylinder chamber (33d), and the outflow end is connected to the discharge pipe (65). The second discharge flow path (82) has an inflow end constituted by discharge ports (P12, P13) connected to the inner cylinder chamber (33b) and the outer cylinder chamber (33c) of the second compression mechanism (30), The outflow end is connected to the discharge pipe (66). The third discharge flow path (83) has an inflow end constituted by discharge ports (P12, P13) connected to the inner cylinder chamber (23b) and the outer cylinder chamber (23c) of the first compression mechanism (20), The outflow end is connected to the discharge pipe (64). The fourth discharge flow path (84) has an inflow end constituted by discharge ports (P14, P14) at the innermost cylinder chamber (23a) of the first compression mechanism (20) and the second compression mechanism (30). It is connected to the innermost cylinder chamber (33a).

  The refrigerant from the fourth discharge channel (84) connected to the innermost cylinder chamber (23a) of the first compression mechanism (20) flows upward in the casing (10) through the muffler space (27a) and is discharged. It is discharged out of the casing (10) through the pipe (67). The refrigerant from the fourth discharge flow path (84) connected to the innermost cylinder chamber (33a) of the second compression mechanism section (30) passes through the discharge junction passage (29) formed in the compression mechanism (40). Flows into the muffler space (27a), merges with the refrigerant discharged from the first compression mechanism (20), and is discharged from the discharge pipe (67) to the outside of the casing (10).

  The compression mechanism (40) includes a plurality of discharge valves (88, 88,...). The discharge valve is constituted by a reed valve, for example. This discharge valve (88,88, ...) covers each discharge port (P11, P11, ... P14, P14), and the pressure in each cylinder chamber (23a, ..., 23d, 33a, ..., 33d) When the pressure is lower than the predetermined value, the discharge ports (P11, P11, ... P14, P14) are closed, while the pressure in each cylinder chamber (23a, ..., 23d, 33a, ..., 33d) is higher than the predetermined value. If this happens, the discharge ports (P11, P11,... P14, P14) are opened.

  As shown in FIG. 2, the middle plate (25) discloses a fourth suction flow path (74) and a first discharge flow path (81) which are fluid passages through which an intermediate-pressure refrigerant flows. The fourth suction flow path (74) sucks refrigerant into the cylinder chamber of the fourth stage compression mechanism (the innermost cylinder chambers (23a, 33a) of the first compression mechanism portion (20) and the second compression mechanism portion (30)). Side fluid passage. The first discharge channel (81) discharges the refrigerant to the cylinder chamber of the first stage compression mechanism (the outermost cylinder chambers (23d, 33d) of the first compression mechanism portion (20) and the second compression mechanism portion (30)). Side fluid passage. In the fourth suction flow path (74) and the first discharge flow path (81), refrigerants having intermediate pressures different from each other flow before the fourth stage compression mechanism and after the first stage compression mechanism. ing.

  A pressing mechanism (90) is provided between the middle plate (25) and each piston-side end plate (22c, 32c) to press the piston (22, 32) against the cylinder (21, 31) with the pressure of the working fluid. It has been. The pressing mechanism (90) includes a first seal ring (91) disposed around the rotation center of the piston (22, 32) and a diameter larger than that of the first seal ring (91). A second seal ring (92) disposed on the outer peripheral side of the ring (91), and an annular portion formed between the first seal ring (91) and the second seal ring (92) for introducing a working fluid ( Annular groove) (93a, 93b). This annular part (93a, 93b) is a first annular part (between the first seal ring (91) and the second seal ring (92) on the upper surface of the body part (25a) of the middle plate (25). 93a) and a second annular portion (93b) formed between the first seal ring (91) and the second seal ring (92) on the lower surface of the lid portion (25b) of the middle plate (25). Yes.

  In the compression mechanism (40), as described above, the fourth suction passage (74) and the first discharge passage (81) are formed in the middle plate (25) as a fluid passage through which the intermediate-pressure refrigerant flows. Has been. The middle plate (25) is formed with intermediate pressure introduction passages (96a, 96b) for introducing a part of the refrigerant flowing through the fluid passages (74, 81) into the annular portions (93a, 93b). Yes. The intermediate pressure introduction path (96a, 96b) is connected to the fourth suction flow path (74) and the first annular part (93a) which are the suction parts of the fourth stage compression mechanism in the first compression mechanism part (20). The first intermediate pressure introduction path (96a) that communicates with the first discharge flow path (81) and the second annular portion (93b) that are discharge portions of the first stage compression mechanism in the second compression mechanism portion (30). And a second intermediate pressure introduction passage (96b) communicating therewith.

  Since the pressure of the discharge refrigerant of the first stage compression mechanism is lower than the pressure of the suction refrigerant of the fourth stage compression mechanism, in the present embodiment, the area of the first annular part (93a) is set to the area of the second annular part (93b). By making it smaller than this, a large difference is not generated in the pressing force obtained by each pressing mechanism (90), or substantially the same. In addition, a throttle (not shown) is provided in the first intermediate pressure introduction passage (96a) communicating with the first annular portion (93a) to adjust the pressure of the refrigerant, and balance of the pressing force by each pressing mechanism (90). You may make it take. The areas of the first annular portion (93a) and the second annular portion (93b) are determined so that the pressing force and the separation force are balanced.

Here, if the rotary compressor of Patent Document 1 described in the background art of the present specification is a comparative example, the compressor of this comparative example is installed on the back surface of the end plate portion of the piston in a configuration that performs four-stage compression. The pressing force of the piston against the cylinder is adjusted by adjusting the internal area (An) and the internal pressure (Pn) of one seal ring. As shown in FIG. 9A, the relationship among thrust force Fs, pressing force Ft, separation force Fu, pressure Pn (Pa = high pressure), and area An is
Fs = Ft−Fu
= (Pa · Aa + Pb · Ab) − (Pc · Ac + Pd · Ad)> 0
Thus, in the relationship of Ft> Fu, an attempt is made to obtain an appropriate pressing force that prevents the piston from separating while minimizing the sliding loss between the piston and the cylinder.

  However, since the pressing force is almost determined only by the high pressure and low pressure of the refrigeration cycle, when the intermediate pressure (the suction pressure / discharge pressure of the second and third stages) deviates from the design point, The separation force increases and the piston disengages from the cylinder, the gap between the two increases and leakage between the compression (suction) chambers increases, leading to performance degradation or conversely the separation force decreases. Excessive pressurization increases the contact surface pressure between the piston and the cylinder and increases the thrust loss, resulting in a large performance drop or seizure resulting in a decrease in reliability.

For example, as shown in FIG.
Fs = Ft−Fu
= (Pa · Aa + Pb · Ab) − (Pc · Ac + Pd · Ad) <0
Therefore, the piston is separated from the cylinder due to insufficient pressing force due to the relationship of Ft <Fu.

  On the other hand, in the present embodiment, as shown in FIG. 10, the seal ring is composed of two seal rings, ie, a first seal ring (91) and a second seal ring (92), and an annular portion (93a, 93b) between them. ) Is introduced with an intermediate pressure (Pb) refrigerant. Therefore, even if the operating state changes and the intermediate pressure deviates from the design point, the pressing mechanism (90) can obtain an optimal pressing force that satisfies the relationship of Ft> Fu according to the operating state. In practice, the low pressure of the refrigerant also acts on the outside of the second seal ring (92).

  The first intermediate pressure introduction path (96a) and the second intermediate pressure introduction path (96b) are opposite to the example shown in FIG. 2, and the first compression mechanism section (30) discharges the first stage compression mechanism. The second compression mechanism portion (20) may communicate with the suction portion of the fourth stage compression mechanism and the second annular portion (93b). .

  The detailed configuration of the fluid passages (71, 84) will be described with reference to FIG. 8 which is a cross-sectional view of the main body (25a) of the middle plate (25). As shown in FIGS. 2 and 8, the first discharge channel (81) is a rectangular parallelepiped discharge space (between the body (25a) and the lid (25b)) of the middle plate (25). 81a), and the discharge space (81a) of the first stage compression mechanism and the discharge pipe (65) communicate with each other. The discharge space (81a) communicates with the cylinder chamber (23d, 33d) of the first stage compression mechanism via the discharge port (P11, P11). Further, the lid portion (25b) of the middle plate (25) has a first stage discharge space (81a) and a second annular portion (93b) constituting a part of the first discharge flow path (discharge portion) (81). The second intermediate pressure introduction passage (96b) communicating with the second intermediate pressure passage is formed.

  The suction pipe side flow path (74a) of the fourth suction flow path (74) is formed at a position displaced by a predetermined angle in the circumferential direction with respect to the position of the suction pipe (61) of the fourth stage compression mechanism. The suction pipe (61) and the suction pipe side flow path (74a) are connected by a curved communication path (74c). The first intermediate pressure introduction passage (96a) communicates with the middle plate (25) through the communication passage (74c) and communicates with the suction portion (74) of the fourth-stage compression mechanism and the first annular groove (93a). Is formed. The suction pipe (61) of the fourth stage compression mechanism and the suction pipe (62) of the first stage compression mechanism are actually formed at the same height in FIGS. In order to clearly show the connection relationship between the fluid passages (74, 81), the positions of the suction pipe (61) and the suction pipe (62) are shifted up and down, and the shape of the passage is simplified.

  As shown in FIG. 2, the third discharge flow path (83) includes a discharge space (83a) of a third-stage compression mechanism formed in the bearing portion side front head (16), and the discharge space (83a) and The third discharge channel (83) and the discharge pipe (64) communicate with each other. The fourth discharge flow path (84) includes a discharge space (84a) of the fourth stage compression mechanism formed in the bearing portion side front head (16). In this embodiment, the discharge space (83a) of the third-stage compression mechanism, which is a lower-stage compression mechanism than the fourth-stage compression mechanism, communicates with the muffler space (27a) via the relief mechanism (100). In addition, the discharge space (84a) of the fourth stage compression mechanism, which is the highest stage compression mechanism, also communicates with the muffler space (27a). Therefore, in this embodiment, the discharge space (83a) of the third-stage compression mechanism and the discharge space (84a) of the fourth-stage compression mechanism communicate with each other.

  The middle plate (25), the first compression mechanism (20) disposed above the middle plate (25), and the second compression mechanism (30) disposed below. In the compression mechanism (40), the relief mechanism (100) is provided in the first compression mechanism section (20) located on the upper side.

  The relief mechanism (100) includes a relief port (101) communicating with the discharge space (83a) and the muffler space (27a) of the third stage compression mechanism, and a relief valve (102) attached to the relief port (101). ). For example, a reed valve can be used as the relief valve (102). The relief valve (102) is opened under operating conditions in which the high pressure of the refrigerant circuit decreases and the discharge pressure of the third stage compression mechanism becomes higher than the high pressure.

  Therefore, in this embodiment, when the operating condition is such that the discharge pressure of the third stage compression mechanism exceeds the high pressure of the system (refrigerant circuit), the discharge valve (88) is always open in the fourth stage compression mechanism. Therefore, in the fourth stage compression mechanism, the refrigerant only passes and is not compressed. And since the discharge pressure of a 3rd stage compression mechanism equalizes to the high pressure of a refrigerant circuit and does not raise any more, it can prevent that the discharge pressure of a compressor (1) increases too much.

-Driving action-
Next, the operation of the compressor (1) will be described. Here, the operations of the first and second compression mechanisms (20, 30) are performed in a state where the phases are different from each other by 180 °.

  When the electric motor (50) is started, in the first compression mechanism (20), the rotation of the rotor (52) is transmitted to the first piston (22) via the first eccentric part (53a) of the drive shaft (53). The first piston (22) swings about the center point of the swing bush portion (24c) and moves forward and backward in the longitudinal direction of the first blade (24) together with the first blade (24). . As a result, the first piston (22) revolves while swinging with respect to the first cylinder (21), and is predetermined in the four cylinder chambers (23a, 23b, 23c, 23d) of the first compression mechanism (20). The compression operation is performed.

  At this time, a micron-order fine gap is formed between the tip of the inner blade part (B1) and the surface of the notch part (n1) of the inner piston part (22a), and they are not in contact with each other. . In addition, a micron-order fine gap is formed between the tip of the outer second blade (B3) and the surface of the notch (n2) of the piston side end plate (22c). It becomes. An oil film of lubricating oil is formed in the fine gap. Therefore, leakage of the refrigerant from the high pressure side to the low pressure side of the cylinder chamber (C1, C2) is not a substantial problem.

  In the innermost cylinder chamber (23a) and the outer cylinder chamber (23c), the drive shaft (53) rotates clockwise from the state shown in FIG. 6 (A) and is changed as shown in FIG. 6 (B) to FIG. 6 (D). As the state changes, the volume of the low pressure chamber (23aL, 23cL) increases, and the refrigerant is sucked into the low pressure chamber (23aL, 23cL) from the suction port (P3, P2). Further, when the drive shaft (53) makes one revolution and again enters the state of FIG. 6 (A), the suction of the refrigerant into the low pressure chambers (23aL, 23cL) is completed. The low-pressure chamber (23aL, 23cL) becomes a high-pressure chamber (23aH, 23cH) in which the refrigerant is compressed, and a new low-pressure chamber (23aL, 23cL) is formed across the first blade (24). When the drive shaft (53) further rotates, the suction of the refrigerant is repeated in the low-pressure chamber (23aL, 23cL), while the volume of the high-pressure chamber (23aH, 23cH) decreases, and the refrigerant in the high-pressure chamber (23aH, 23cH) Compressed. When the pressure in the high pressure chamber (23aH, 23cH) reaches a preset value and the differential pressure from the discharge flow path (84, 83) reaches a set value, the discharge valve ( 88, 88) is opened, and the refrigerant is discharged from the fourth discharge passage (84) and the third discharge passage (83) to the outside of the first compression mechanism section (20).

  In the outermost cylinder chamber (23d), the drive shaft (53) rotates clockwise from the state shown in FIG. 7 (A) and changes from the state shown in FIG. 7 (B) to FIG. 7 (D). Accordingly, the volume of the low pressure chamber (23dL) increases, and the refrigerant is sucked into the low pressure chamber (23dL) from the suction port (P1). Further, when the drive shaft (53) makes one revolution and again enters the state of FIG. 7 (A), the suction of the refrigerant into the low pressure chamber (23dL) is completed. The low pressure chamber (23dL) becomes a high pressure chamber (23dH) in which the refrigerant is compressed, and a new low pressure chamber (23dL) is formed across the first blade (24). When the drive shaft (53) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (23dL), while the volume of the high pressure chamber (23dH) is reduced, and the refrigerant is compressed in the high pressure chamber (23dH). When the pressure in the high pressure chamber (23dH) reaches a predetermined value and the differential pressure from the discharge flow path (81) reaches a set value, the discharge valve (88) is opened by the pressure of the refrigerant in the high pressure chamber (23dH), and the refrigerant Is discharged from the first discharge channel (81) to the outside of the first compression mechanism (20).

  On the other hand, in the inner cylinder chamber (23b), the drive shaft (53) rotates clockwise from the state of FIG. 6 (C) and changes to the state of FIGS. 6 (D) to 6 (B). Accordingly, the volume of the low pressure chamber (23bL) increases, and the refrigerant is sucked into the low pressure chamber (23bL) from the suction port (P2). Further, when the drive shaft (53) makes one revolution and again enters the state of FIG. 6 (C), the suction of the refrigerant into the low pressure chamber (23bL) is completed. The low pressure chamber (23bL) becomes a high pressure chamber (23bH) in which the refrigerant is compressed, and a new low pressure chamber (23bL) is formed across the first blade (24). When the drive shaft (53) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (23bL), while the volume of the high pressure chamber (23bH) is reduced, and the refrigerant is compressed in the high pressure chamber (23bH). When the pressure in the high pressure chamber (23bH) reaches a predetermined value and the differential pressure with respect to the discharge flow path (83) reaches a set value, the discharge valve (88) is opened by the pressure of the refrigerant in the high pressure chamber (23bH), and the refrigerant Is discharged from the discharge flow path (83) to the outside of the first compression mechanism (20).

  The outer cylinder chamber (23c) and the inner cylinder chamber (23b) are approximately 180 degrees different in refrigerant suction start timing and discharge start timing. As a result, the discharge pulsation is reduced, and vibration and noise are reduced.

  On the other hand, in the second compression mechanism (30), the rotation of the rotor (52) is transmitted to the second piston (32) via the second eccentric part (53b) of the drive shaft (53), and the second piston ( 32) swings with the center point of the swing bush portion (34c) as the swing center, and moves forward and backward in the longitudinal direction of the second blade (34) together with the second blade (34). As a result, the second piston (32) revolves while swinging with respect to the second cylinder (31), and is predetermined in the four cylinder chambers (33a, 33b, 33c, 33d) of the second compression mechanism (30). The compression operation is performed.

  The compression operation in the second compression mechanism section (30) is substantially the same as the compression operation in the first compression mechanism section (20), and the refrigerant is compressed in each cylinder chamber (33a, 33b, 33c, 33d). The In each cylinder chamber (33a, 33b, 33c, 33d), the pressure in the high pressure chamber (33aH, 33bH, 33cH, 33dH) becomes a predetermined value and the differential pressure from each discharge flow path (84, 83, 83, 81) Reaches the set value, the discharge valve (88, 88, 88, 88) is opened by the pressure of the refrigerant in the high-pressure chamber (33aH, 33bH, 33cH, 33dH), and the refrigerant flows into each discharge channel (84, 82, 82). , 81) is discharged to the outside of the second compression mechanism section (30).

  During the operation of the compression mechanism (40), the refrigerant flows from the suction pipe (62) to the outermost cylinder chamber (23d) of the first compression mechanism section (20), which is the cylinder chamber of the first stage compression mechanism, and the second compression mechanism. The air is sucked into the outermost cylinder chamber (33d) of the section (30), compressed, and discharged from the cylinder chamber of the first stage compression mechanism through the discharge pipe (65). For example, during the cooling operation, as shown in FIG. 10 (A), the refrigerant discharged from the cylinder chamber of the first stage compression mechanism is cooled and then cooled from the suction pipe (63) to the cylinder chamber of the second stage compression mechanism. Is sucked into the outer cylinder chamber (33c) and the inner cylinder chamber (33b) of the second compression mechanism (30) and further compressed, and discharged from the cylinder chamber of the second stage compression mechanism through the discharge pipe (66). Is done. After the refrigerant discharged from the cylinder chamber of the second stage compression mechanism is cooled, the outer cylinder chamber (23c) of the first compression mechanism section (20) which is the cylinder chamber of the third stage compression mechanism from the suction pipe (60). ) And the inner cylinder chamber (23b), further compressed, and discharged from the cylinder chamber of the third stage compression mechanism through the discharge pipe (64). After the refrigerant discharged from the cylinder chamber of the third-stage compression mechanism is cooled, the innermost cylinder chamber of the first compression mechanism section (20), which is the cylinder chamber of the fourth-stage compression mechanism, from the suction pipe (61) ( 23a) and the innermost cylinder chamber (33a) of the second compression mechanism section (30) and further compressed, and discharged from the cylinder chamber of the fourth stage compression mechanism through the discharge pipe (67).

  The refrigerant discharged from the cylinder chamber of the fourth-stage compression mechanism sequentially flows through a radiator, an expansion mechanism, and an evaporator of a refrigerant circuit (not shown), and is sucked into the compressor (1) again. A refrigeration cycle is performed by sequentially repeating a compression stroke in the compressor (1), a heat release stroke in the radiator, an expansion stroke in the expansion mechanism, and an evaporation stroke in the evaporator.

  On the other hand, when the cylinder capacity of each stage compression mechanism is determined based on the provision of an intermediate cooling mechanism between each stage of multistage compression and performing cooling operation, cooling by outside air is performed during heating operation, and intermediate cooling is performed. Since it is not performed, the discharge pressure of the compressor (1) may increase too much.

  Specifically, when the operating condition of the refrigerant circuit changes during operation of the compressor (1) and the high pressure decreases, the pressure in the casing (10) of the compressor (1) also decreases to the high pressure of the refrigerant circuit. As a result, the pressure in the fourth discharge flow path (84) and the muffler space (27a) also decreases. Here, under operating conditions in which the high pressure of the refrigerant circuit is lower than the discharge pressure of the third stage compression mechanism, the pressure of the discharge space (83a) of the third stage compression mechanism is the discharge space (84a) of the fourth stage compression mechanism. ) (See the broken line in FIG. 12A). This is because in FIG. 12B, the third stage compression mechanism attempts to compress the refrigerant to the suction volume (Vc4) of the fourth stage compression mechanism.

  On the other hand, in this embodiment, the relief valve (102) opens under such operating conditions, and the discharge pressure of the third stage compression mechanism is equalized to the pressure in the casing, that is, the high pressure of the refrigerant circuit. Further, the pressure of the refrigerant sucked into the fourth stage compression mechanism is also substantially equal to the pressure in the casing (10). Therefore, in the fourth stage compression mechanism, the discharge valve (88) remains open, and the refrigerant flows out of the cylinder chamber (22a, 33a) into the casing (10) without being compressed.

  Thus, in this embodiment, when the operating condition is such that the discharge pressure of the third stage compression mechanism is higher than the high pressure of the refrigerant circuit, the relief valve (102) opens and the discharge valve of the fourth stage compression mechanism. (88) is also kept open to suppress an excessive increase in the pressure of the refrigerant discharged from the compression mechanism (40).

  During operation of the compression mechanism (40), intermediate pressure refrigerant is supplied from the fluid passages (74, 81) formed in the middle plate (25) to the annular portions (93a, 93b). . Specifically, the fourth stage compression mechanism is moved from the fourth suction flow path (74), which is the suction part of the fourth stage compression mechanism, to the first annular part (93a) via the first intermediate pressure introduction path (96a). Part of the suction refrigerant is introduced. Further, the refrigerant discharged from the first-stage compression mechanism is discharged from the first discharge flow path (81), which is the discharge section of the first-stage compression mechanism, to the second annular portion (93b) through the second intermediate pressure introduction path (96b). Some are introduced.

  In accordance with the pressure of the refrigerant discharged from the first stage compression mechanism being lower than the pressure of the suction refrigerant of the fourth stage compression mechanism, in this embodiment, the area of the first annular portion (93a) is reduced to the second annular portion (93b). ) Is smaller than that of the first compression mechanism (20) and the second compression mechanism (30). In this embodiment, the pressing force and the separation force are balanced as shown in FIG. 10 in both the first compression mechanism portion (20) and the second compression mechanism portion (30), so that the cylinders (21, 31). It is also possible to prevent the refrigerant from leaking from between the piston and the piston (22, 32) and the cylinder (21, 31) and the piston (22, 32) from being seized.

-Effect of Embodiment 1-
According to this embodiment, an intermediate pressure fluid passing through the fourth suction passage (74) and the first discharge passage (81) formed in the middle plate (25) is introduced into each annular portion (93a, 93b). Therefore, the pressing force is generated. Since the pressing force is generated using the intermediate pressure as described above, the pressing force changes accordingly when the operating state changes and the intermediate pressure fluctuates. Therefore, it is possible to easily obtain the optimum pressing force according to the operating condition, so that the refrigerant leaks from the cylinder chamber (23a to 23d, 33a to 33d) due to insufficient pressing force, and the performance decreases or friction due to excessive pressing. It is possible to prevent the reliability from being lowered due to loss.

  Further, in the present embodiment, the configuration in which the pressing force is generated by the intermediate pressure refrigerant is formed by forming the fluid passage (74, 81) and the intermediate pressure introduction passage (96a, 96b) in the middle plate (25), and introducing the intermediate pressure. Since the path (96a, 96b) is simply connected to the annular portion (93a, 93b), the structure is not complicated, and cost and reliability can be prevented from being lowered.

  In the present embodiment, the fourth suction passage connected to the innermost cylinder chamber (23a, 33a) in the first compression mechanism section (20) and the second compression mechanism section (30) each having four cylinder chambers. (74) and the first discharge passage (81) connected to the outermost cylinder chambers (23d, 33d) are formed in the middle plate, and the suction passages (the second passage compression mechanism and the third passage compression mechanism) 72, 73) and discharge passage (82, 83) are formed in the front head (14) and rear head (17), so the structure of the fluid passage (74, 81) can be simplified and compressed. It is possible to prevent the structure of the mechanism (40) from becoming complicated.

  Furthermore, according to the present embodiment, the relief mechanism (100) is simply provided in the discharge space (83a) of the third-stage compression mechanism, and the discharge space (third-stage compression mechanism) of the third-stage compression mechanism is reduced when the high-pressure pressure of the system decreases. The refrigerant flows from 83a) to the discharge space (84a) of the fourth-stage compression mechanism, and the pressure of the discharge space (83a) of the third-stage compression mechanism becomes substantially the same as the high pressure of the system. Therefore, since it is possible to prevent the discharge pressure of the compressor (1) from increasing too much, it is possible to prevent the efficiency of the cycle from being lowered with a simple configuration and to suppress leakage loss.

  In the present embodiment, the cylinder volume of the second stage compression mechanism and the cylinder volume of the third stage compression mechanism are made equal so that the second stage discharge volume and the third stage suction volume are appropriately balanced. By simply providing the relief mechanism (100) in the third stage compression mechanism, it is possible to easily realize a configuration that can prevent the discharge pressure of the compressor from rising excessively.

  In the present embodiment, the relief mechanism (100) is provided in the first compression mechanism (20) on the upper side of the middle plate (25), and the refrigerant is discharged upward from the compression mechanism (40). Yes. Here, an oil sump for storing lubricating oil is provided at the bottom of the casing of the compressor (1), and the third-stage compression mechanism is connected to the second compression mechanism (30) below the middle plate (25). When it is provided and the refrigerant is discharged downward, it is necessary to provide a discharge cover on the rear head (17) side or to provide a refrigerant discharge passage in the compression mechanism (40), which may complicate the configuration. However, according to the present embodiment, it is possible to prevent the configuration from becoming complicated.

-Modification of Embodiment 1-
(Modification 1)
Modification 1 shown in FIG. 13 is an example in which the configuration of the intermediate pressure introduction path (96a, 96b) is different from the embodiment of FIG. In the first modification, the first intermediate pressure introduction path (96a) includes a first discharge flow path (81) that is a discharge portion of the first stage compression mechanism and a first annular portion ( 93a), and the second intermediate pressure introduction passage (96b) includes a first discharge passage (81) and a second annular portion which are discharge portions of the first stage compression mechanism in the second compression mechanism portion (30). (93b).

  In Modification 1, since the pressure of the flowing refrigerant is the same in both the first intermediate pressure introduction path (96a) and the second intermediate pressure introduction path (96b), the first annular portion (93a) and the second annular pressure section It is not necessary to adjust the area of the portion (93b) or to provide a throttle in any of the intermediate pressure introduction paths (96a, 96b).

  The rest of the configuration including the relief mechanism (100) provided in the discharge space (83a) of the third-stage compression mechanism is the same as that of the embodiment of FIG.

  Also in this modified example 1, since the pressing force and the separation force are balanced as shown in FIG. 9A in both the first compression mechanism portion (20) and the second compression mechanism portion (30), the cylinder (21, It is possible to prevent the refrigerant from leaking between 31) and the pistons (22, 32) and the cylinders (21, 31) and the pistons (22, 32) from being seized. Therefore, it is possible to prevent the performance of the compressor (1) from deteriorating and to prevent the reliability of the compressor (1) from deteriorating.

  In addition, a fluid passage (81) through which an intermediate pressure refrigerant flows is formed in the middle plate (25), and the annular portions (93a, 93b) between the fluid passage (81) and the two seal rings (91, 92) are formed. Since the intermediate pressure refrigerant is introduced through the intermediate pressure introduction path (96a, 96b) and a complicated mechanism is not required, it is possible to prevent the configuration from becoming complicated.

  Further, since the relief mechanism (100) is provided in the discharge space (83a) of the third stage compression mechanism, even under operating conditions where the high pressure of the system is lower than the discharge pressure of the third stage compression mechanism. The discharge pressure of the compressor (1) can be prevented from rising too much.

(Modification 2)
Modification 2 shown in FIG. 14 is an example in which the configuration of the intermediate pressure introduction path (96a, 96b) is different from the embodiment of FIG. 2 and Modification 1 of FIG. In the second modification, the first intermediate pressure introduction path (96a) includes a fourth suction flow path (74) that is a suction part of the fourth compression mechanism and a first annular part (93a) in the first compression mechanism part (20). The second intermediate pressure introduction path (96b) communicates with the fourth suction flow path (74), which is the suction portion of the fourth stage compression mechanism (40) in the second compression mechanism section (30), and the second passage. It communicates with the annular part (93b).

  In the second modification, as in the first modification, both the first intermediate pressure introduction path (96a) and the second intermediate pressure introduction path (96b) have the same refrigerant pressure. It is not necessary to adjust the areas of (93a) and the second annular portion (93b) or to provide a throttle in any of the intermediate pressure introduction paths (96a, 96b).

  Moreover, the other structure is the same as the embodiment of FIG. 2 and the modification 1 of 12 including the point which has provided the relief mechanism (100) in the discharge space (83a) of a 3rd stage compression mechanism.

  Also in the second modified example, the pressing force and the separation force are balanced as shown in FIG. 10 in both the first compression mechanism portion (20) and the second compression mechanism portion (30), so that the cylinders (21, 31) and It is possible to prevent the refrigerant from leaking between the pistons (22, 32) and the cylinders (21, 31) and the pistons (22, 32) from being seized. Therefore, it is possible to prevent the performance of the compressor (1) from deteriorating and to prevent the reliability of the compressor (1) from deteriorating.

  Further, a fluid passage (74) through which the intermediate pressure refrigerant flows is formed in the middle plate (25), and the annular portions (93a, 93b) between the two fluid seals (91, 92) from the fluid passage (74). Since the intermediate pressure refrigerant is introduced through the intermediate pressure introduction path (96a, 96b) and a complicated mechanism is not required, it is possible to prevent the configuration from becoming complicated.

  Further, since the relief mechanism (100) is provided in the discharge space (83a) of the third stage compression mechanism, even under operating conditions where the high pressure of the system is lower than the discharge pressure of the third stage compression mechanism. The discharge pressure of the compressor (1) can be prevented from rising too much.

<< Embodiment 2 of the Invention >>
A second embodiment of the present invention shown in FIG. 15 will be described. Embodiment 2 is an example in which the present invention is applied to a compression mechanism that performs three-stage compression.

  In the second embodiment, the inner diameter of the outermost cylinder portion (21c, 31c) is larger than the outer shape of the piston side end plate portion (22c, 32c), and the space formed between them is the outermost portion that compresses the refrigerant in the first embodiment. In contrast to the outer cylinder chamber (23d, 33d), the second embodiment is an invalid space (23e, 33e) in which refrigerant is not compressed. The first suction passage (71) shown in FIG. 2 is not formed in the middle plate (25), and the suction pipe (62) is not connected.

  In the second embodiment, the space that is the outermost cylinder chamber (23d, 33d) in FIG. 2 is the invalid space (23e, 33e). Therefore, the middle plate (25) is shown in FIG. The discharge ports (P11, P11) and the first discharge flow path (81) are not formed, and the discharge pipe (65) is not connected.

  The middle plate (25) of FIG. 2 is composed of two members, a main body (25a) and a lid (25b), whereas in the present embodiment, the discharge port (P11, P11) and the first discharge flow path (81), which is an internal space having a larger volume than that, are not formed in the middle plate (25). Therefore, the middle plate (25) of this embodiment is composed of one member.

  The cylinder chamber of the first stage compression mechanism is composed of an inner cylinder chamber (33b) and an outer cylinder chamber (33c) of the second compression mechanism section (30). The cylinder chamber of the second stage compression mechanism is composed of an inner cylinder chamber (23b) and an outer cylinder chamber (23c) of the first compression mechanism section (20). The cylinder chamber of the third stage compression mechanism is composed of an innermost cylinder chamber (23a) of the first compression mechanism section (20) and an innermost cylinder chamber (33a) of the second compression mechanism section (30).

  As described above, in the second embodiment, the first-stage compression mechanism described in the first embodiment in FIG. 2 is not used, and the second-stage compression mechanism, the third-stage compression mechanism, and the fourth-stage compression mechanism in the first embodiment are used. The compression mechanisms constitute a first stage compression mechanism, a second stage compression mechanism, and a third stage compression mechanism, respectively.

  In the second embodiment, for convenience of explanation, the second suction channel (72), the third suction channel (73), and the fourth suction channel (74) in FIG. These are referred to as the second suction channel (72) and the third suction channel (73). Further, the second discharge channel (82), the third discharge channel (83), and the fourth discharge channel (84) in FIG. 2 are replaced with the first discharge channel (81) and the second discharge channel (82, respectively). ) And the third discharge channel (83).

  In the inner cylinder chamber (33b) and the outer cylinder chamber (33c) of the second compression mechanism section (30) that is the cylinder chamber of the first stage compression mechanism, the suction pipe (63) connects the first suction flow path (71). The discharge pipe (66) is connected via the first discharge flow path (81). In the inner cylinder chamber (23b) and the outer cylinder chamber (23c) of the first compression mechanism section (20), which is the cylinder chamber of the second stage compression mechanism, the suction pipe (60) is connected to the second suction flow path (72). The discharge pipe (64) is connected via the second discharge flow path (82). The innermost cylinder chamber (23a) of the first compression mechanism section (20), which is the cylinder chamber of the third stage compression mechanism, and the innermost cylinder chamber (33a) of the second compression mechanism section (30) are connected to the suction pipe (61). Are connected via a third suction flow path (73) and communicated with a space in the casing (10) via a third discharge flow path (83) and a discharge merging passage (29).

  The first intermediate pressure introduction passage (96a) communicates with the third suction passage (73) and the first annular portion (93a) which are suction portions of the third-stage compression mechanism in the first compression mechanism (20). The second intermediate pressure introduction path (96b) communicates with the third suction passage (73) and the second annular portion (93b) which are the suction portions of the third-stage compression mechanism in the second compression mechanism portion (30). doing. The first intermediate pressure introduction path (96a) and the second intermediate pressure introduction path (96b) are constituted by one passage, and this passage and the third suction passage (73) are connected by a communication passage (96c). Yes.

  In the second embodiment, similar to the first and second modifications of the first embodiment, the refrigerant flowing through the first intermediate pressure introduction passage (96a) and the refrigerant flowing through the second intermediate pressure introduction passage (96b) have the same pressure. Therefore, it is not necessary to adjust the areas of the first annular portion (93a) and the second annular portion (93b) or to provide a throttle in any of the intermediate pressure introduction paths (96a, 96b).

  Moreover, the relief mechanism (100) is provided in the 1st compression mechanism part (20) arrange | positioned above a middle plate (25). This relief mechanism (100) includes a relief port (101) communicating with the discharge space (82a) and the muffler space (27a) of the second-stage compression mechanism, and a relief valve (102) attached to the relief port (101). ). The relief valve (102) is opened when the high-pressure pressure in the refrigerant circuit decreases and the operating condition is such that the discharge pressure of the second-stage compression mechanism exceeds the high-pressure pressure in the refrigerant circuit.

  Therefore, in the second embodiment, when the discharge pressure of the second stage compression mechanism exceeds the high pressure of the system (refrigerant circuit), the third stage compression mechanism always keeps the discharge valve (88) open. Therefore, in the third stage compression mechanism, the refrigerant only passes and is not compressed, and the high pressure of the refrigerant can be prevented from rising too much.

  And also in this Embodiment 2, by having comprised the pressing mechanism (90) as mentioned above, both a 1st compression mechanism part (20) and a 2nd compression mechanism part (30) have pressing force and separation force. Since it balances as shown in FIG. 10, the refrigerant may leak from between the cylinder (21, 31) and the piston (22, 32), or the cylinder (21, 31) and the piston (22, 32) may be seized. Absent. Therefore, it is possible to prevent the performance of the compressor (1) from deteriorating and to prevent the reliability of the compressor (1) from deteriorating.

Further, a fluid passage (74) through which the intermediate pressure refrigerant flows is formed in the middle plate (25), and the annular portions (93a, 93b) between the two fluid seals (91, 92) from the fluid passage (74). the intermediate pressure introduction passage (96a, 96b) have so as to introduce the intermediate-pressure refrigerant in, since a complex mechanism is not required, is also suppressed the configuration becomes complicated.

  In addition, since the relief mechanism (100) is configured as described above, when the operating condition of the refrigerant circuit changes during operation of the compressor (1) and the high pressure is reduced, the casing (10 ) Also tends to decrease to the high pressure of the refrigerant circuit, the pressure in the third discharge flow path (83) and the muffler space (27a) also decreases. Here, when the high pressure of the refrigerant circuit becomes lower than the discharge pressure of the second stage compression mechanism, the pressure of the discharge space (82a) of the second stage compression mechanism is changed to the fourth discharge flow path (83) and the muffler space (27a). Higher than the pressure.

  Therefore, under this operating condition, the relief valve (102) opens, and the discharge pressure of the second stage compression mechanism becomes equal to the pressure in the casing (10), that is, the high pressure of the refrigerant circuit. Further, since the pressure of the refrigerant sucked into the third stage compression mechanism becomes substantially equal to the pressure in the casing (10), the discharge valve (88) of the third stage compression mechanism remains open. Therefore, in the third stage compression mechanism, the refrigerant flows out of the cylinder chamber (23a, 33a) into the casing (10) without being compressed.

Thus, in this embodiment, when the discharge pressure of the second stage compression mechanism is higher than the high pressure of the refrigerant circuit, the relief valve (102) opens and the discharge valve ( 88) since also kept opened, the pressure of the refrigerant discharged from the compression mechanism (40) is prevented from excessively rising.

  Other configurations, operations, and effects are the same as those in the first embodiment.

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

  For example, although the four-stage compression mechanism is described in the first embodiment and the three-stage compression mechanism is described in the second embodiment, the present invention is a compression mechanism (40 that compresses a working fluid such as a refrigerant in three or more stages. The compressor (1) provided with a) is applicable.

  Moreover, in the said embodiment, although the cylinder volume of a 2nd stage compression mechanism and the cylinder volume of a 3rd stage compression mechanism are made the same, both cylinder volumes do not necessarily need to be the same.

  Moreover, in the said embodiment, although the relief mechanism (100) is provided in the 1st compression mechanism part (20), you may provide a relief mechanism (100) in the 2nd compression mechanism part (30) depending on the case.

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

  As described above, the present invention is useful for a rotary compressor including an eccentric rotation type compression mechanism in which a plurality of cylinder chambers are formed between a piston and a cylinder to perform multistage compression.

1 Rotary compressor
20 First compression mechanism
21 1st cylinder
22 First piston
23a Innermost cylinder chamber
23b Inner cylinder chamber
23c Outer cylinder chamber
23d Outermost cylinder chamber
25 middle plate
30 Second compression mechanism
31 2nd cylinder
32 2nd piston
33a Innermost cylinder chamber
33b Inner cylinder chamber
33c Outer cylinder chamber
33d Outermost cylinder chamber
40 Compression mechanism
83a Discharge space
84a Discharge space
100 relief mechanism

Claims (4)

In the refrigerant circuit that performs the refrigeration cycle, during the cooling operation, the refrigerant is supplied from the low stage side to the high stage side via the intermediate cooler to perform multistage compression, and during the heating operation, the high stage from the low stage side without using the intermediate cooler Equipped with a compression mechanism (40) that performs multi-stage compression by directly supplying refrigerant to the side, and the compression mechanism (40) is eccentrically rotatable relative to the cylinder (21, 31) and the cylinder (21, 31) And a plurality of cylinder chambers (23a to 23d, 33a to 33d) formed between the cylinder (21, 31) and the piston (22, 32). A rotary compressor configured to compress a fluid in three or more stages,
A relief mechanism (100) communicating with the discharge space (84a) of the highest stage compression mechanism is provided in the discharge space (83a) of the lower stage compression mechanism on the lower stage side than the highest stage compression mechanism. Features a rotary compressor. In claim 1,
The compression mechanism (40) is a four-stage compression mechanism,
Rotational compression characterized in that the relief mechanism (100) is provided in the discharge space (83a) of the third-stage compression mechanism and communicates with the discharge space (84a) of the fourth-stage compression mechanism Machine. Between the cylinder (21, 31), the piston (22, 32) configured to rotate eccentrically with respect to the cylinder (21, 31), and between the cylinder (21, 31) and the piston (22, 32) A rotary compressor including a plurality of formed cylinder chambers (23a to 23d, 33a to 33d) and a compression mechanism (40) for compressing a working fluid in three or more stages,
A relief mechanism (100) communicating with the discharge space (84a) of the highest stage compression mechanism is provided in the discharge space (83a) of the lower stage compression mechanism on the lower stage side with respect to the highest stage compression mechanism,
The compression mechanism (40) is a four-stage compression mechanism,
The relief mechanism (100) is provided in the discharge space (83a) of the third-stage compression mechanism, and is configured to communicate with the discharge space (84a) of the fourth-stage compression mechanism,
A rotary compressor characterized in that the cylinder volume of the second stage compression mechanism is equal to the cylinder volume of the third stage compression mechanism. In any one of Claims 1-3,
The compression mechanism (40) includes a middle plate (25), a first compression mechanism portion (20) disposed above the middle plate (25) and a second compression mechanism portion ( 30)
The rotary compressor according to claim 1, wherein the relief mechanism (100) is provided in the first compression mechanism section (20).

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