Rotary compressors and refrigeration systems

Abstract

This suppresses seizure between the piston and the blocking member in a rotary compressor. [Solution] In the rotary compressor, in an axial view, the region between the blade (38) and the thin-walled portion (52) that overlaps with the cylinder chamber (S1) is designated as the first region (77), and the region between the blade (38) and the intake port that overlaps with the cylinder chamber (S1) is designated as the second region (78). When the piston (35) is at bottom dead center, the gap (CR1) between the portion of the first region (77) at the outer edge of the piston (35) and the portion of the first region (77) of the closing member (50) is larger than the gap (CR2) between the portion of the second region (78) of the piston (35) and the portion of the second region (78) of the closing member (50).

Description

Technical Field

[0001] The present disclosure relates to a rotary compressor and a refrigeration apparatus including the same. The rotary compressor is a compressor that compresses gas in a compression chamber formed in a cylinder by eccentrically rotating a piston in the cylinder. The rotary compressor generally has a blade for partitioning the compression chamber.

Background Art

[0002] Conventionally, a rotary compressor including an annular piston that orbits along the inner surface of a cylinder chamber of a cylinder, a blade connected to the piston, and closing members respectively disposed on both axial end surfaces of the end surface of the piston and the cylinder is known. In such a rotary compressor, the refrigerant sucked into the cylinder chamber from the suction hole is compressed by the rotation of the piston and discharged from the discharge port.

[0003] For example, in the rotary compressor described in Patent Document 1, a second portion that is a portion excluding the first portion of the piston is made to protrude more than the first portion, which is a portion near the blade of the piston and the blade.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a rotary compressor, the gap between the piston and the closing member is designed to smooth the turning operation of the piston and suppress seizure between the piston and the closing member.

[0006] In the rotary compressor described in Patent Document 1, the gap between the piston and the occluding member is designed to suppress seizure between the piston and the occluding member near the intake port where the amount of thermal expansion of the cylinder is small. However, after diligent research by the inventors of the present invention, it was found that in order to suppress seizure between the piston and the occluding member, it is necessary to consider not only the effects of heat but also the pressure difference between the inside and outside of the cylinder chamber.

[0007] The purpose of this disclosure is to suppress seizure between the piston and the occluding member in a rotary compressor. [Means for solving the problem]

[0008] A first aspect of the technology disclosed herein relates to a rotary compressor. The rotary compressor includes cylinders (31, 41, 331, 341, 431) having cylinder chambers (S1, S2) inside, pistons (35, 45, 235, 245) that revolve along the inner surface of the cylinder chambers (S1, S2) without rotating, a rotating shaft (90) that revolves the pistons (35, 45, 235, 245), and a shaft connected to the pistons (35, 45, 235, 245) and the cylinder chambers (S1, S2 The cylinder chamber (S1, S2) comprises blades (38, 48) that divide the chamber into an intake space (71, 75) and a discharge space (72, 76), an intake port (17, 18, 317, 318, 417) that supplies refrigerant to the intake space (71, 75), and closing members (50, 56, 250, 256, 350, 355, 356, 450, 456) that close both axial ends of the rotating shaft (90) in the cylinder chamber (S1, S2), and the piston At position (35, 45, 235, 245), the rotating shaft (90) includes eccentric portions (91, 92) that are eccentric with respect to the center (X) of the rotating shaft (90), and the blocking member (50, 56, 250, 256, 350, 355, 356, 450, 456) is formed in a range including the periphery of the discharge port (51, 57, 251, 257) that communicates with the discharge space (72, 76) and discharges compressed refrigerant from the discharge space (72, 76), and the blocking member (50, 56, 250, 256, 350, 3 The piston (35, 45, 235, 245) includes a thin-walled portion (52, 58, 252, 258) which is thinner in the axial direction than the other parts of the piston (55, 356, 450, 456), and in an axial view, the first line segment (L1) is defined as the line segment connecting the first point (P1) closest to the bottom dead center of the piston (35, 45, 235, 245) among the intersections where the outer edge of the thin-walled portion (52, 58, 252, 258) and the inner edge of the cylinder (31, 41) intersect, and among the intersections where the intake port (17, 18, 317, 318, 417) and the inner edge of the cylinder (31, 41) intersect, the piston ( Let the second line segment (L2) be the line segment connecting the second point (P2) closest to the bottom dead center of the piston (35, 45, 235, 245) and the center (X) of the rotation axis (90). The first region (77, 277) is the region between the blade (38, 48) and the first line segment (L1) that overlaps with the cylinder chamber (S1, S2) when the piston (35, 45, 235, 245) is at bottom dead center, and the region between the blade (38, 48) and the second line segment (L2) that overlaps with the cylinder chamber (S1, S2) when the piston (35, 45, 235, 245) is at bottom dead center. The region is designated as the second region (78,278), and when the piston (35,45,235,245) is at its bottom dead center, the gap (CR1) between the portion of the first region (77,277) and the portion of the first region (77,277) of the closing member (50,56,250,256,350,355,356,450,456) at the outer edge of the piston (35,45,235,245) is the portion of the second region (78,278) of the piston (35,45,235,245) and the portion of the closing member (50,56,250,256,350,355,356,450,It is larger than the gap (CR2) between the portion of the second region (78,278) of 456).

[0009] In the first embodiment, the refrigerant tends to become hot near the discharge ports (51, 57, 251, 257), and the pressure outside the cylinder chambers (S1, S2) tends to be higher than the pressure inside the cylinder chambers (S1, S2). As a result, both thermal expansion of the pistons (35, 45, 235, 245) due to the pressure difference may occur. The rotary compressor can suppress seizure between the piston (35, 45, 235, 245) and the blocking member (50, 56, 250, 256, 350, 355, 356, 450, 456) by increasing the gap between the piston (35, 45, 235, 245) and the blocking member (50, 56, 250, 256, 350, 355, 356, 450, 456) in the first region (77, 277) near the discharge ports (51, 57, 251, 257).

[0010] A second aspect of the technology disclosed herein is that, in the first aspect, the portion of the piston (35, 45, 235, 245) in the first region (77, 277) has a first recess (81) in which the axial surface is recessed compared to the portion of the piston (35, 45, 235, 245) in the second region (78, 278).

[0011] In the second embodiment, the gap between the pistons (35, 45, 235, 245) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456) can be increased with simple processing. The rotary compressor can suppress seizure between the pistons (35, 45, 235, 245) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456).

[0012] A third aspect of the technology disclosed herein, in the second aspect, the first recess (81) is positioned in an axial view to include a 90° range on the discharge port (51, 57, 251, 257) side, with respect to the center line (CL) of the blade (38, 48) passing through the centers (DC1, DC2) of the eccentric portions (91, 92).

[0013] In a third embodiment, the first recess (81) is located in a range that can be located near the discharge ports (51, 57, 251, 257) of the piston (35, 45, 235, 245). The rotary compressor can suppress seizure between the piston (35, 45, 235, 245) and the blocking members (50, 56, 250, 256, 350, 355, 356, 450, 456).

[0014] A fourth aspect of the technology disclosed herein is that, in the second or third aspect, the first recess (81) is located only on the side (35a, 45b) of the piston (35, 45, 235, 245) that is closer to the discharge port (51, 57, 251, 257) out of the axial sides (35a, 35b, 45a, 45b).

[0015] In the fourth embodiment, the range in which the gap between the pistons (35, 45, 235, 245) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456) becomes large can be narrowed. The rotary compressor can achieve high compression efficiency while suppressing seizure between the pistons (35, 45, 235, 245) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456).

[0016] A fifth aspect of the technology disclosed herein is, in the second or third aspect, the first recess (81) is located on the side (35a, 45b) of the piston (35, 45, 235, 245) that is closer to the discharge port (51, 57, 251, 257) of the axial sides (35a, 35b, 45a, 45b) of the piston (35, 45, 235, 245) that is further away from the discharge port (51, 57, 251, 257) of the axial sides (35a, 35b, 45a, 45b) of the piston (35, 45, 235, 245) has a second recess (82) that is recessed on the opposite side of the first recess (81) in an axial view, at a position that overlaps with the first recess (81).

[0017] In the fifth embodiment, seizure between the pistons (35, 45, 235, 245) and the closing members (50, 56, 250, 256, 350, 355, 356, 450, 456) located on both sides of the cylinders (31, 41, 331, 341, 431) in the axial direction can be suppressed.

[0018] A sixth aspect of the technology disclosed herein is that, in any one of the second to fifth aspects, the first recess (81) is deeper than the suction-side portion of the piston (35, 45, 235, 245) in the circumferential direction of the piston (35, 45, 235, 245) when the piston (35, 45, 235, 245) is at top dead center, with respect to the portion of the piston (35, 45, 235, 245) closer to the discharge port (51, 57, 251, 257).

[0019] In the sixth embodiment, the range in which the gap between the pistons (35, 45, 235, 245) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456) becomes large can be narrowed. The rotary compressor can achieve high compression efficiency while suppressing seizure between the pistons (35, 45, 235, 245) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456).

[0020] The seventh aspect of the technology disclosed herein is that, in any one of the second to sixth aspects, the piston (35, 45, 235, 245) has a third recess (83) that is located in a different part in the circumferential direction of the piston (35, 45, 235, 245) from the first recess (81) and whose axial surface is recessed.

[0021] In the seventh aspect, even if there is a portion that is prone to deformation other than the vicinity of the discharge ports (51, 57, 251, 257) in the piston (35, 45, 235, 245), the rotary compressor can suppress seizure of the piston and the closing member.

[0022] The eighth aspect of the technology disclosed herein is that, in any one of the first to seventh aspects, the gap between at least a part of the blade (38, 48) and the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456) is larger than the gap (CR2) between the suction-side part of the piston (35, 45, 235, 245) and the suction-side part of the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456).

[0023] In the eighth aspect, even if the blade (38, 48) is deformed by a high-temperature and high-pressure refrigerant, the rotary compressor can further suppress seizure of the blade (38, 48).

[0024] The ninth aspect of the technology disclosed herein is that, in the eighth aspect, at least a part of the blade (38, 48) is located on the discharge port (51, 57, 251, 257) side and is a part where the axial surface (38b, 48c) is recessed compared to the part on the suction port (17, 18, 317, 318, 417) side.

[0025] In the ninth aspect, by recessing the part that is prone to thermal expansion with respect to the part that is less prone to thermal expansion, the rotary compressor can increase the partitioning performance of the blade (38, 48) while suppressing seizure of the blade (38, 48).

[0026] A tenth aspect of the technology disclosed herein is that, in the eighth or ninth aspect, at least a part of the blades (38, 48) is deeper with respect to the suction-side portion of the pistons (35, 45, 235, 245) as the part is closer to the connection portion between the pistons (35, 45, 235, 245) and the blades (38, 48).

[0027] In the tenth aspect, the range in which the gap between the blades (38, 48) and the closing members (50, 56, 250, 256, 350, 355, 356, 450, 456) increases can be narrowed. The rotary compressor can suppress seizure of the blades (38, 48) while enhancing the partitioning performance of the blades (38, 48).

[0028] An eleventh aspect of the technology disclosed herein is that, in any one of the first to tenth aspects, the portion of the first region (77, 277) of the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456) has a fourth recess (252a, 258a) in which the surface on the side of the cylinder chambers (S1, S2) is recessed as compared with the portion of the second region (78, 278) of the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456), and the fourth recess (252a, 258a) is located only around the discharge ports (51, 57, 251, 257) in the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456).

[0029] In the eleventh aspect, the range in which the gap between the pistons (35, 45, 235, 245) and the closing members (50, 56, 250, 256, 350, 355, 356, 450, 456) increases can be narrowed. The rotary compressor can suppress seizure between the pistons (35, 45, 235, 245) and the closing members (50, 56, 250, 256, 350, 355, 356, 450, 456) while enhancing the compression efficiency.

[0030] A twelfth aspect of the technology disclosed herein is that, in any one of the first to eleventh aspects, the refrigerant is carbon dioxide.

[0031] In the twelfth embodiment, carbon dioxide tends to become high pressure compared to other refrigerants, so the area around the discharge ports (51, 57, 251, 257) tends to become high pressure, and the parts of the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456) around the discharge ports (51, 57, 251, 257) tend to deform. Even when using carbon dioxide, the rotary compressor can suppress seizure between the piston (35, 45, 235, 245) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456).

[0032] A thirteenth aspect of the technology disclosed herein relates to a refrigeration system. The refrigeration system comprises a rotary compressor (1,201,301,401) as described in any one of the first to twelfth aspects. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 is a piping diagram of a refrigeration system equipped with a rotary compressor according to Embodiment 1. [Figure 2] Figure 2 is a longitudinal cross-sectional view of a rotary compressor. [Figure 3] Figure 3 is a cross-sectional view of the first cylinder. [Figure 4] Figure 4 is a cross-sectional view of the second cylinder. [Figure 5] Figure 5 is a cross-sectional view taken along the line IV-IV in Figure 3. [Figure 6] Figure 6 shows the rear head as viewed from the axial internal space side. [Figure 7] Figure 7 shows the operation of the compression mechanism. [Figure 8] Figure 8 shows the positional relationship between the first recess and the discharge port. [Figure 9] Figure 9 is a perspective view of the first piston. [Figure 10A] Figure 10A is a view of the first piston from the radial direction. [Figure 10B] Figure 10B is a view of the second piston from the radial direction. [Figure 11] Figure 11 is a cross-sectional view showing the gap between the piston and the front head. [Figure 12] Figure 12 is a view of the piston according to Modification 1 from the radial direction. [Figure 13] Figure 13 is a perspective view of the piston according to modified example 2. [Figure 14] Figure 14 shows the positional relationship between the first recess of the piston and the discharge port according to Modification 2. [Figure 15] Figure 15 is a perspective view of the piston according to Modification 3. [Figure 16] Figure 16 is a perspective view of the piston according to Modification 4. [Figure 17] Figure 17 is a perspective view of the piston according to Modification 5. [Figure 18] Figure 18 is a cross-sectional view taken along the line XVIII-XVIII in Figure 17. [Figure 19] Figure 19 is a cross-sectional view of the area near the first discharge port of the rotary compressor according to Embodiment 2. [Figure 20] Figure 20 is a cross-sectional view of the area near the second discharge port of the rotary compressor according to Embodiment 2. [Figure 21] Figure 21 is a longitudinal cross-sectional view of a rotary compressor having two suction pipes. [Figure 22] Figure 22 is a longitudinal cross-sectional view of a rotary compressor having a single-cylinder compression mechanism. [Modes for carrying out the invention]

[0034] Embodiments of this disclosure will be described in detail below with reference to the drawings. This disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of ​​this disclosure. Since the drawings are for conceptual explanation of this disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding. In the following description, unless otherwise specified, "axial direction" refers to the direction in which the rotation axis extends, "radial direction" refers to the direction radiating from the rotation axis, and "circumferential direction" refers to the circumferential direction centered on the rotation axis. Also, "up" and "down" indicate the direction when the rotary compressor (1) is viewed from the front. Furthermore, hatching may be omitted in the drawings to facilitate understanding of the explanation.

[0035] <Embodiment 1> (1) Refrigeration equipment Figure 1 shows a refrigeration system (100) equipped with a rotary compressor (1) according to this first embodiment. Hereinafter, the rotary compressor (1) may be simply referred to as the compressor (1). The refrigeration system (100) is, for example, an air conditioning system that air-conditions a room. The refrigeration system (100) has an outdoor unit (7) located outside and an indoor unit (8) located inside. The outdoor unit (7) is equipped with a compressor (1), an accumulator (2), a four-way switching valve (3), an outdoor heat exchanger (4a), an expansion valve (5), and an economizer heat exchanger (4b). The indoor unit (8) is equipped with an indoor heat exchanger (6). The outdoor unit (7) and the indoor unit (8) are connected via a connecting pipe (9a) to form a refrigerant circuit (9).

[0036] The compressor (1) in this embodiment is of the type in which blades (38, 48) rotate eccentrically while connected to specific positions on the outer circumference of pistons (35, 45), and is a so-called swing type in which the blades (38, 48) and pistons (35, 45) are integrally formed. The compressor (1) compresses low-pressure gaseous refrigerant into high-pressure gaseous refrigerant. The compressor (1) is driven by a compressor motor. A portion of the intermediate-pressure refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) is supplied to the compressor (1), and intermediate injection is performed. The intermediate pressure is a predetermined pressure between the pressure of the gaseous refrigerant drawn into the compressor (1) (low pressure) and the pressure of the gaseous refrigerant discharged from the compressor (1) (high pressure). The refrigerant is not particularly limited, but for example, carbon dioxide (CO2).

[0037] The four-way directional valve (3) switches the connection state of the internal piping of the outdoor unit (7). When the refrigeration unit (100) is operating in cooling mode, the four-way directional valve (3) is in the connection state shown by the dashed line in Figure 1. When the refrigeration unit (100) is operating in heating mode, the four-way directional valve (3) is in the connection state shown by the solid line in Figure 1.

[0038] The outdoor heat exchanger (4a) exchanges heat between the refrigerant circulating in the refrigerant circuit (9) and the outdoor air. The outdoor heat exchanger (4a) has a refrigerant flow path through which the refrigerant flows and heat transfer fins that come into contact with the outdoor air. During cooling operation, the outdoor heat exchanger (4a) functions as a refrigerant radiator (condenser), and during heating operation, it functions as a refrigerant absorber (evaporator).

[0039] The expansion valve (5) is an electrically operated valve or solenoid valve with adjustable opening. The expansion valve (5) reduces the pressure of the refrigerant flowing through the internal piping of the outdoor unit (7). The expansion valve (5) controls the flow rate of the refrigerant flowing through the internal piping of the outdoor unit (7).

[0040] The accumulator (2) is located in the piping on the suction side of the compressor (1). The accumulator (2) separates the gas-liquid mixed refrigerant flowing through the refrigerant circuit into gaseous refrigerant and liquid refrigerant, and stores the liquid refrigerant. The gaseous refrigerant separated by the accumulator (2) is sent to the suction port of the compressor (1).

[0041] The economizer heat exchanger (4b) is positioned between the outdoor heat exchanger (4a) and the expansion valve (5). The economizer heat exchanger (4b) performs heat exchange between the refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) and the refrigerant flowing through the economizer piping (9b). The economizer piping (9b) is a pipe that branches off from the refrigerant circuit (9) between the economizer heat exchanger (4b) and the expansion valve (5) and is connected to the injection piping (9c). An economizer valve (9d) is attached to the economizer piping (9b). The refrigerant flowing through the economizer piping (9b) is depressurized by the economizer valve (9d) and then exchanges heat with the refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) in the economizer heat exchanger (4b). The refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) and the refrigerant that has undergone heat exchange in the economizer heat exchanger (4b) are supplied to the injection piping (9c) as refrigerant at an intermediate pressure.

[0042] The refrigeration system (100) includes a refrigerant circuit (9). A compressor (1), a four-way switching valve (3), an outdoor heat exchanger (4a), an expansion valve (5), an indoor heat exchanger (6), and an economizer heat exchanger (4b) are connected to the refrigerant circuit (9). The refrigeration cycle is performed by the flow of refrigerant through the refrigerant circuit (9).

[0043] The refrigeration system (100) performs heating and cooling operations by switching the four-way switching valve (3). In cooling operation, the first refrigeration cycle is performed. Specifically, in the connection state shown by the dashed line in Figure 1, the indoor heat exchanger (6) functions as an evaporator and the outdoor heat exchanger (4a) functions as a radiator. In heating operation, the second refrigeration cycle is performed. Specifically, in the connection state shown by the solid line in Figure 1, the indoor heat exchanger (6) functions as a radiator and the outdoor heat exchanger (4a) functions as an evaporator.

[0044] (2) Rotary compressor As shown in Figure 2, the compressor (1) comprises a sealed container (10), an electric motor (20), and a compression mechanism (30). The electric motor (20) and the compression mechanism (30) are housed within the sealed container (10). The compressor (1) is configured as a so-called high-pressure dome type, in which the refrigerant compressed in the compression mechanism (30) is discharged into the internal space (R) of the sealed container (10), and the internal space (R) becomes high-pressure.

[0045] (2-1) Rotary Compressor The sealed container (10) is formed in an elongated shape. Specifically, the sealed container (10) comprises a cylindrical body (11) extending vertically, an upper lid (12) that closes the upper end of the body (11), and a lower lid (13) that closes the lower end of the body (11). A discharge pipe (15) is inserted through the upper part of the body (11). A suction pipe (14) is located at the lower part of the body (11).

[0046] (2-2) Electric motor The electric motor (20) is housed in a sealed container (10). The electric motor (20) drives the compression mechanism (30). Within the electric motor (20), it is positioned above the mounting plate (54). The electric motor (20) has a cylindrical stator (21) along the inner circumferential surface of the body (11) and a rotor (22) positioned inside the stator (21).

[0047] (2-3) Rotation axis The rotating shaft (90) is positioned to extend vertically within the sealed container (10). The rotating shaft (90) is driven by an electric motor (20). The upper part of the rotating shaft (90) is connected to the rotor (22) of the electric motor (20).

[0048] The lower part of the rotating shaft (90) has, in order from top to bottom, an upper shaft portion (90a), a first eccentric portion (91), an intermediate shaft portion (90b), a second eccentric portion (92), and a lower shaft portion (90c). The upper shaft portion (90a), the first eccentric portion (91), the intermediate shaft portion (90b), the second eccentric portion (92), and the lower shaft portion (90c) are integrally formed with respect to each other.

[0049] The first eccentric portion (91) and the second eccentric portion (92) are eccentric with respect to the axis of the rotation shaft (90). The first eccentric portion (91) and the second eccentric portion (92) are formed with a larger diameter than the upper shaft portion (90a), the intermediate shaft portion (90b), and the lower shaft portion (90c). The eccentric direction of the first eccentric portion (91) with respect to the rotation center axis of the rotation shaft (90) is 180° different from the eccentric direction of the second eccentric portion (92) with respect to the rotation center axis of the rotation shaft (90).

[0050] The intermediate shaft portion (90b) is positioned between the first eccentric portion (91) and the second eccentric portion (92). The intermediate shaft portion (90b) connects the first eccentric portion (91) and the second eccentric portion (92).

[0051] (2-4) Compression mechanism As shown in Figure 2, the compression mechanism (30) is housed within a sealed container (10). The compression mechanism (30) compresses the inhaled refrigerant and discharges it into the internal space (R) of the sealed container (10). The compression mechanism (30) is fixed to a mounting plate (54) which is fixed to the inner circumferential surface of the body (11). Specifically, the compression mechanism (30) is positioned on the lower surface of the mounting plate (54). The compression mechanism (30) has two cylinders. The compression mechanism (30) comprises a rotating shaft (90), a front head (50), a first cylinder (31), a first piston (35), a first blade (38), a middle plate (55), a second cylinder (41), a second piston (45), a second blade (48), and a rear head (56). The front head (50), first cylinder (31), middle plate (55), second cylinder (41), and rear head (56) are fixed together by a number of through bolts (B) so as not to move relative to each other.

[0052] (2-4-1) Cylinder As shown in Figures 2 to 4, the first cylinder (31) and the second cylinder (41) are thick-walled disc-shaped members. The first cylinder (31) and the second cylinder (41) have cylinder bores (32, 42), blade housing holes (33, 43), intake ports (17, 18), injection passages (61, 62), and injection ports (63, 64).

[0053] The cylinder bores (32, 42) are circular holes that penetrate the cylinders (31, 41) in the thickness direction. The cylinder bores (32, 42) are formed in the central part of the cylinders (31, 41). The first cylinder bore (32) of the first cylinder (31) houses the first piston (35). The second cylinder bore (42) of the second cylinder (41) houses the second piston (45).

[0054] In the first cylinder (31), a first cylinder chamber (S1) is formed between the wall surface of the first cylinder bore (32) and the first piston (35). In the second cylinder (41), a second cylinder chamber (S2) is formed between the wall surface of the second cylinder bore (42) and the second piston (45).

[0055] The blade housing holes (33, 43) are holes that extend radially outward from the inner circumferential surface of the cylinder (31, 41) (i.e., the outer edge of the cylinder bore (32, 42)). These blade housing holes (33, 43) penetrate the cylinder (31, 41) in the thickness direction. The first blade (38) is housed in the first blade housing hole (33) of the first cylinder (31). The second blade (48) is housed in the second blade housing hole (43) of the second cylinder (41).

[0056] The first cylinder (31) has a first passage (16a) which is part of the intake passage (16). The first passage (16a) is a bottomed hole extending in the thickness direction of the first cylinder (31). The first passage (16a) is located to the right of the first blade housing hole (33) in Figure 3. The second cylinder (41) has a second passage (16b) which is part of the intake passage (16). The second passage (16b) penetrates through the thickness direction of the second cylinder (41). The second passage (16b) is located to the right of the second blade housing hole (43) in Figure 4.

[0057] The intake ports (17, 18) extend from the intake passage (16) toward the cylinder chambers (S1, S2). The first intake port (17) of the first cylinder (31) extends from the first passage (16a) toward the first cylinder chamber (S1). The second intake port (18) of the second cylinder (41) extends from the second passage (16b) toward the second cylinder chamber (S2). The intake ports (17, 18) extend toward the cylinder chambers (S1, S2) so as to be closer to the blade housing holes (33, 43) than the intake passage (16).

[0058] The injection passages (61, 62) are passages that supply refrigerant to the cylinder chambers (S1, S2) separately from the intake passage (16). The first injection passage (61) of the first cylinder (31) is located to the left of the first blade housing hole (33) in Figure 3. In other words, the first injection passage (61) of the first cylinder (31) is located on either side of the first blade housing hole (33), and the first passage ( It is located on the opposite side from 6a). The second injection passage (62) of the second cylinder (41) is located to the left of the second blade housing hole (43) in Figure 4. In other words, the second injection passage (62) of the second cylinder (41) is located on the opposite side from the second passage (16b), with the second blade housing hole (43) in between.

[0059] The injection ports (63, 64) extend from the injection passages (61, 62) toward the cylinder chambers (S1, S2). The injection ports (63, 64) extend toward the cylinder chambers (S1, S2) so as to be closer to the blade housing holes (33, 43) than the injection passages (61, 62).

[0060] (2-4-2) Piston The first piston (35) is housed within the first cylinder (31). The first piston (35) revolves inside the first cylinder chamber (S1). The first piston (35) is configured to slide against both the front head (50) and the middle plate (55).

[0061] The first piston (35) is formed in an annular shape with the center (DC1) of the first eccentric portion (91) as its center. The first piston (35) is formed in a slightly thick-walled cylindrical shape. The first eccentric portion (91) of the rotating shaft (90) is inserted through the first piston (35). As the first eccentric portion (91) rotates, the first piston (35) pivots along the inner circumferential surface of the first cylinder chamber (S1) of the first cylinder (31).

[0062] The second piston (45) is identical to the first piston (35) in shape, dimensions, and material. The first piston (35) and the second piston (45) are positioned inverted relative to each other in the vertical direction.

[0063] The second piston (45) is housed within the second cylinder (41). The second piston (45) revolves within the second cylinder chamber (S2). The second piston (45) is configured to slide against both the rear head (56) and the middle plate (55).

[0064] The second piston (45) is formed in an annular shape with the center (DC2) of the second eccentric portion (92) as its center. The second piston (45) is formed in a slightly thick-walled cylindrical shape. The second eccentric portion (92) of the rotating shaft (90) is inserted through the second piston (45). As the second eccentric portion (92) rotates, the second piston (45) pivots along the inner circumferential surface of the second cylinder chamber (S2) of the second cylinder (41).

[0065] (2-4-3) Blade As shown in Figures 3 and 4, the first blade (38) and the second blade (48) are slightly thick rectangular flat members. The first blade (38) is integrally formed with the first piston (35). The second blade (48) is integrally formed with the second piston (45). The blades (38, 48) extend radially outward from the outer circumferential surface of the pistons (35, 45).

[0066] The first blade (38) fits into the first blade housing hole (33). The first blade (38) is sandwiched from both sides by a pair of first bushes (70) provided on the first cylinder (31). The first blade (38), which is integrated with the first piston (35), is supported by the first cylinder (31) via the first bushes (70) so that it can swing freely and move forward and backward.

[0067] The first blade (38) divides the first cylinder chamber (S1) into a first intake space (71) and a first discharge space (72). The first blade (38) restricts the rotation of the first piston (35) itself when the first piston (35) is rotating. As a result, the first piston (35) rotates along the inner surface of the first cylinder chamber (S1) without rotating.

[0068] The second blade (48) fits into the second blade housing hole (43). The second blade (48) is sandwiched from both sides by a pair of second bushes (74) provided on the second cylinder (41). The second blade (48), which is integrated with the second piston (45), is supported by the second cylinder (41) via these second bushes (74) so ​​that it can swing freely and move forward and backward.

[0069] The second blade (48) divides the second cylinder chamber (S2) into a second intake space (75) and a second discharge space (76). The second blade (48) restricts the rotation of the second piston (45) itself when the second piston (45) is swirling. As a result, the second piston (45) swirls along the inner surface of the second cylinder chamber (S2) without rotating.

[0070] (2-4-4) Front Head As shown in Figure 2, the front head (50) closes the axial end of the first cylinder (31). Specifically, the front head (50) closes the upper end surface (the surface on the motor (20) side) of the first cylinder (31). The front head (50) is an example of a closing member of this disclosure. The front head (50) comprises a first main body portion (50a) and an upper bearing portion (50b). The first main body portion (50a) and the upper bearing portion (50b) are integrally formed.

[0071] The first main body (50a) is formed in a generally circular, thick plate shape. The lower surface of the first main body (50a) is in close contact with the upper end surface of the first cylinder (31). The upper bearing portion (50b) is formed in a cylindrical shape that extends from the first main body (50a) toward the electric motor (20) side (upper side in Figure 2). The upper bearing portion (50b) is positioned in the center of the first main body (50a). The upper bearing portion (50b) rotatably supports the upper shaft portion (90a) of the rotating shaft (90).

[0072] As shown in Figure 5, the first main body (50a) has a first discharge port (51). The first discharge port (51) penetrates the first main body (50a) in the thickness direction. The first discharge port (51) connects the internal space (R) and the first discharge space (72).

[0073] The portion of the first main body (50a) surrounding the first discharge port (51) is a first thin-walled portion (52) that is thinner in the axial direction than other portions. The portion of the first thin-walled portion (52) that is continuous with the first discharge port (51) is slightly thicker than other portions of the first thin-walled portion (52).

[0074] A first discharge valve (53) is provided at the first discharge port (51). The first discharge valve (53) is positioned to cover the first discharge port (51). The first discharge valve (53) moves away from the first discharge port (51) when the pressure of the refrigerant in the first discharge space (72) exceeds a predetermined value. When the first discharge valve (53) moves away from the first discharge port (51), the refrigerant is discharged through the first discharge port (51) from the first discharge space (72) into the internal space (R). After the refrigerant has been discharged into the internal space (R), the first discharge valve (53) again covers the first discharge port (51).

[0075] (2-4-5) Middle Plate As shown in Figure 2, the middle plate (55) is sandwiched axially between the first cylinder (31) and the second cylinder (41). The middle plate (55) closes the axial ends of the first cylinder (31) and the second cylinder (41). Specifically, the middle plate (55) closes the lower end surface of the first cylinder (31) and the upper end surface of the second cylinder (41). The middle plate (55) is an example of a closing member of this disclosure.

[0076] A central hole is formed in the middle of the middle plate (55), passing through it axially. The intermediate shaft portion (90b) of the rotating shaft (90) is inserted through the central hole.

[0077] The middle plate (55) has an intermediate passage (16c) which is part of the intake passage (16). The intermediate passage (16c) penetrates the middle plate (55) in the axial direction. The intermediate passage (16c) connects the first passage (16a) and the second passage (16b).

[0078] Although detailed illustrations are omitted, the middle plate (55) has a passage that connects the first injection passage (61) and the second injection passage (62).

[0079] (2-4-6) Rear Head As shown in Figure 2, the rear head (56) closes the axial end of the second cylinder (41). Specifically, the rear head (56) closes the lower end surface of the second cylinder (41) (the surface opposite to the electric motor (20)). The rear head (56) is an example of a closing member of this disclosure. The rear head (56) comprises a second main body (56a), a lower bearing portion (56b), and an expansion portion (56c). The second main body (56a) and the lower bearing portion (56b) are a single component.

[0080] As shown in Figure 6, the second main body (56a) is formed in a generally circular, thick plate shape. The lower surface of the second main body (56a) is in close contact with the lower end surface of the second cylinder (41). The lower bearing portion (56b) is formed in a cylindrical shape extending from the second main body (56a) to the opposite side of the second cylinder (41) (the lower side in Figure 2). The lower bearing portion (56b) is located in the center of the second main body (56a). The lower bearing portion (56b) rotatably supports the lower shaft portion (90c) of the rotating shaft (90).

[0081] The expansion portion (56c) extends radially outward from the second main body portion (56a). The expansion portion (56c) has a first insertion hole (19) into which the suction tube (14) is inserted, and a second insertion hole (60) into which an injection tube (not shown) is inserted. The first insertion hole (19) and the second insertion hole (60) each extend radially.

[0082] A lower passage (16d), which is part of the suction passage (16), extends from the first insertion hole (19). The lower passage (16d) extends upward along the axial direction from the tip of the first insertion hole (19). The upper end of the lower passage (16d) communicates with the second passage (16b).

[0083] A lower injection passage (65) extends from the second insertion hole (60). The lower injection passage (65) extends upward along the axial direction from the tip of the second insertion hole (60). The upper end of the lower injection passage (65) communicates with the second injection passage (62).

[0084] As shown in Figures 5 and 6, the second main body (56a) has a second discharge port (57). The second discharge port (57) penetrates the second main body (56a) in the thickness direction. The second discharge port (57) connects the internal space (R) and the second discharge space (76).

[0085] The portion of the second main body (56a) surrounding the second discharge port (57) is a second thin-walled portion (58) that is thinner in the axial direction than other portions. The portion of the second thin-walled portion (58) that is continuous with the second discharge port (57) is slightly thicker than other portions of the second thin-walled portion (58).

[0086] A second discharge valve (59) is provided at the second discharge port (57). The second discharge valve (59) is positioned to cover the second discharge port (57). The second discharge valve (59) moves away from the second discharge port (57) when the refrigerant pressure in the second discharge space (76) exceeds a predetermined value. When the second discharge valve (59) moves away from the second discharge port (57), the refrigerant is discharged through the second discharge port (57) from the second discharge space (76) into the internal space (R). After the refrigerant has been discharged into the internal space (R), the second discharge valve (59) again covers the second discharge port (57).

[0087] (3) Operating Next, the operation of the compressor (1) will be explained with reference to Figure 7. The refrigerant compression operation by the first cylinder (31) and the first piston (35) and the refrigerant compression operation by the second cylinder (41) and the second piston (45) are basically the same, differing only by a 180° phase difference. In the following explanation, the refrigerant compression operation by the first cylinder (31) and the first piston (35) will be described in detail, while the refrigerant compression operation by the second cylinder (41) and the first piston (35) will not be explained.

[0088] In the compressor (1), when the electric motor (20) is started and the rotor (22) is rotated, the rotating shaft (90 The ) rotates, and the first eccentric part (91) rotates eccentrically. Then, the eccentric rotation of the first eccentric part (91) Consequently, the first piston (35) rotates along the inner surface of the first cylinder (31) while restricting its rotation. It turns.

[0089] The suction stroke for drawing refrigerant into the first cylinder chamber (S1) will now be described. When the rotation angle of the rotating shaft (90) rotates slightly from the state of 0° (state in Figure 7(A)), the contact point between the first piston (35) and the first cylinder (31) passes the inner circumference end of the first suction port (17). At this time, the suction of refrigerant into the first suction space (71) begins.

[0090] Refrigerant is drawn in from the suction pipe (14) through the suction passage (16) and the first suction port (17). As the rotation angle of the rotating shaft (90) increases, the volume of the first suction space (71) gradually increases, and the amount of refrigerant drawn into the first suction space (71) increases (as shown in Figures 7(B) to (H)). This refrigerant suction stroke continues until the rotation angle of the rotating shaft (90) reaches 360°, after which the process transitions to the discharge stroke.

[0091] The discharge stroke, in which the refrigerant is compressed and discharged in the first cylinder chamber (S1), will now be described. When the rotation angle of the rotating shaft (90) rotates slightly from the state of 0° (state in Figure 7(A)), the contact point between the first piston (35) and the first cylinder (31) passes the inner circumference end of the first intake port (17) again. At this time, the containment of the refrigerant in the first intake space (71) is completed.

[0092] The first intake space (71), which was connected to the first intake port (17), becomes the first discharge space (72), which is connected only to the first discharge port (51). From this state, compression of the refrigerant in the first discharge space (72) begins. As the rotation angle of the rotating shaft (90) increases, the volume of the first discharge space (72) decreases and the pressure in the first discharge space (72) increases. When the pressure in the first discharge space (72) exceeds a predetermined pressure, the first discharge valve (53) opens.

[0093] When the first discharge valve (53) opens, the refrigerant in the first discharge space (72) is discharged from the first discharge port (51), flows into the internal space (R) within the sealed container (10), and is then discharged to the outside of the compressor (1) via the discharge pipe (15). This refrigerant discharge stroke continues until the rotation angle of the rotating shaft (90) reaches 360°, after which the process transitions to the suction stroke.

[0094] In this manner, the intake stroke and discharge stroke are repeated in the first cylinder chamber (S1). In the second cylinder chamber (S2), the intake stroke and discharge stroke are repeated with a 180° phase difference relative to the first cylinder chamber (S1). As a result, the compressor (1) continuously compresses the refrigerant.

[0095] (4) Burnout during operation During the discharge stroke, when the rotation angle of the rotating shaft (90) reaches 360°, in other words, when the pistons (35,45) are at top dead center, the volume of the discharge space (72,76) becomes approximately zero. On the other hand, high-pressure refrigerant remains near the discharge ports (51,57) in the internal space (R). Since the area near the first discharge port (51) of the front head (50) is the first thin-walled section (52), when the pressure difference between the inside and outside of the first cylinder chamber (S1) becomes large, the first thin-walled section (52) deforms to penetrate into the first cylinder chamber (S1). Similarly, near the second discharge port (57) of the rear head (56), since it is the second thin-walled section (58), when the pressure difference between the inside and outside of the second cylinder chamber (S2) becomes large, the second thin-walled section (58) deforms to penetrate into the second cylinder chamber (S2).

[0096] On the other hand, the portion of the piston (35,45) near the discharge ports (51,57) is exposed to the compressed and heated refrigerant. In particular, in this embodiment 1, the same portion of the piston (35,45) is exposed to the heated refrigerant. For this reason, when the piston (35,45) is at top dead center, the portion of the piston (35,45) near the discharge ports (51,57) is more susceptible to thermal expansion than the portion of the piston (35,45) on the suction side, that is, the portion of the piston (35,45) near the suction ports (17,18). The cylinder (31,41) also undergoes thermal expansion, but the piston (35,45) has a lower heat capacity than the cylinder (31,41), so the deformation due to thermal expansion is greater. For this reason, when the first piston (35) undergoes thermal expansion, the first piston (35) deforms to move closer to the front head (50) and the middle plate (55). Similarly, when the second piston (45) expands due to heat, it deforms to move closer to the rear head (56) and the middle plate (55).

[0097] If both deformation of the first thin-walled portion (52) and the second thin-walled portion (58) and thermal expansion of the first piston (35) and the second piston (45) occur, the axial gap between the first thin-walled portion (52) and the first piston (35), and between the second thin-walled portion (58) and the second piston (45) may become zero. If the gap becomes zero, seizure will occur between the first thin-walled portion (52) and the first piston (35), and between the second thin-walled portion (58) and the second piston (45).

[0098] Furthermore, the blades (38, 48) are also exposed to high-temperature refrigerant, making them more susceptible to thermal expansion compared to the intake side portions of the pistons (35, 45). As a result, seizing may occur between the first thin-walled portion (52) and the first blade (38), and between the second thin-walled portion (58) and the second blade (48).

[0099] To address these challenges, in this embodiment 1, the surface shapes of the pistons (35, 45) and blades (38, 48) were modified.

[0100] (5) Piston surface shape The surface shapes of the pistons (35, 45) and blades (38, 48) will be described below. Note that the first piston (35) and the second piston (45), and the first blade (38) and the second blade (48) have shapes that are inverted vertically from each other. Therefore, the surface shapes of the first piston (35) and the first blade (38) will be mainly described below, and a detailed explanation of the surface shapes of the second piston (45) and the second blade (48) will be omitted.

[0101] The first piston (35) has a first recess (81) on its axial surface. Figure 8 shows the area where the first recess (81) is provided. As shown in Figure 8, in an axial view, the intersection point where the periphery of the first discharge valve (53) and the inner edge of the first cylinder (31) intersect is defined as the first point (P1) that is closer to the bottom dead center of the first piston (35), and the line segment connecting the first point (P1) and the center (X) of the rotation axis (90) is defined as the first line segment (L1). Also, in an axial view, the intersection point where the first intake port (17) and the inner edge of the first cylinder (31) intersect is defined as the second point (P2) that is closer to the bottom dead center of the first piston (35), and the line segment connecting the second point (P2) and the center (X) of the rotation axis (90) is defined as the second line segment (L2). In an axial view, when the first piston (35) is at bottom dead center, the region on the first discharge space (72) side of the first blade (38) between the first discharge space (72) side and the first line segment (L1) is defined as the region overlapping with the first cylinder bore (32), and in particular the region overlapping with the first cylinder chamber (S1), which is defined as the first region (77). In an axial view, when the first piston (35) is at bottom dead center, the region on the first intake space (71) side of the first blade (38) between the first intake space (71) side and the second line segment (L2) is defined as the region overlapping with the first cylinder bore (32), and in particular the region overlapping with the first cylinder chamber (S1), which is defined as the second region (78). The first recess (81) is located within the range including the first region (77) when the first piston (35) is at bottom dead center. Specifically, the first recess (81) is positioned in an axial view, with respect to the center line (CL) of the first blade (38) passing through the center (DC1) of the first eccentric portion (91), and includes a 90° range on the first discharge port (51) side, with the center (DC1) of the first eccentric portion (91) as the center (DC1). The first recess (81) is positioned from the inner edge to the outer edge of the first piston (35) in the radial direction. The first recess (81) is also formed to include the entire connecting portion (38a) between the first piston (35) and the first blade (38). As a result, when the first piston (35) is at top dead center, the first recess (81) is positioned in a range that overlaps with the first discharge port (51).

[0102] As shown in Figures 9 and 10A, the first recess (81) is a portion of the axial surface of the first piston (35) that is recessed compared to the portion of the second region (78) (hereinafter simply referred to as "the portion of the second region (78)") when the first piston (35) is at its bottom dead center. The first recess (81) is formed only on the surface of the first piston (35) that is closer to the first discharge port (51) among the two axial surfaces of the first piston (35). Specifically, in the first piston (35), the first recess (81) is located only on the upper surface (35a) of the first piston (35) and not on the lower surface (35b).

[0103] In this embodiment 1, the first recess (81) is configured as a stepped portion. The bottom of the first recess (81) forms a plane that extends radially. The axial thickness of the first blade (38) is thinner than the thickness of the second region (78) portion of the first piston (35). The upper surface (38b) of the first blade (38) is flush with the bottom surface of the first recess (81). The lower surface (38c) of the first blade (38) is flush with the lower surface of the first piston (35).

[0104] In Figures 9 and 10A, the depth of the first recess (81) is shown enlarged to make it easier to understand that the first recess (81) is formed. In reality, the depth of the first recess (81) is 2 μm to 20 μm, preferably 2 μm to 10 μm, and more preferably 2 μm to 5 μm.

[0105] The first recess (81) is formed by machining the lower surface of the first piston (35). The machining method for forming the first recess (81) is not particularly limited, but examples include laser machining or roller burnishing.

[0106] As shown in Figure 11, the formation of the first recess (81) increases the axial gap between the first piston (35) and the front head (50). Specifically, when the first piston (35) is at bottom dead center, the axial gap (CR1) between the portion of the first region (77) at the outer edge of the first piston (35) and the portion of the first region (77) of the front head (50) is larger than the axial gap (CR2) between the portion of the second region (78) of the first piston (35) and the portion of the second region (78) of the front head (50). The same is true at the inner edge of the first piston (35). Note that "the portion of the first region (77) of the front head (50)" means not only the entire portion included in the first region (77) of the front head (50), but also includes only a portion within the first region (77) of the front head (50).

[0107] As shown in Figure 10B, for the second piston (45), the first recess (81) is located only on the lower surface (45b) of the second piston (45) and not on the upper surface (45a). Also, the upper surface (48b) of the second blade (48) is flush with the upper surface (45a) of the second piston (45), and the lower surface (48c) of the second blade (48) is flush with the bottom surface of the first recess (81). The range in which the first recess (81) is located on the second piston (45) is the same as the range in which the first recess (81) is located on the first piston (35).

[0108] Although detailed illustrations are omitted, when the second piston (45) is at bottom dead center, the axial clearance (CR1) between the portion of the first region (77) at the outer edge of the second piston (45) and the portion of the first region (77) of the rear head (56) is greater than the axial clearance (CR2) between the portion of the second region (78) of the second piston (45) and the portion of the second region (78) of the rear head (56). The same is true at the position of the inner edge of the second piston (45). Note that "the portion of the first region (77) of the rear head (56)" means not only the entire portion included in the first region (77) of the rear head (56), but also includes only a portion within the first region (77) of the rear head (56).

[0109] (6) Effects of Embodiment 1 In the rotary compressor (1) according to this embodiment 1, when the first piston (35) is at bottom dead center, the axial gap (CR1) between the portion of the first region (77) at the outer edge of the first piston (35) and the portion of the first region (77) of the front head (50) is larger than the axial gap (CR2) between the portion of the second region (78) of the first piston (35) and the portion of the second region (78) of the front head (50). As a result, even if deformation of the thin-walled portions (52, 58) occurs when the outside of the cylinder chambers (S1, S2) becomes more pressure than the inside, and thermal expansion of the pistons (35, 45) occurs, it is possible to prevent the axial gap between the first piston (35) and the front head (50) and the axial gap between the second piston (45) and the rear head (56) from becoming zero. Therefore, the rotary compressor (1) according to this embodiment 1 can suppress seizure between the pistons (35, 45) and the front head (50) and rear head (56).

[0110] In particular, the outer edges of the pistons (35, 45) are in direct contact with the compressed refrigerant, making them prone to large expansion due to thermal expansion. Because the gap (CR1) is large at the outer edges of the pistons (35, 45), the rotary compressor (1) according to this embodiment 1 can effectively suppress seizure between the pistons (35, 45) and the front head (50) and rear head (56).

[0111] In the rotary compressor (1) according to this first embodiment, the first region (77) of the piston (35, 45) has a first recess (81) whose axial surface is recessed compared to the second region (78) of the piston (35, 45). The first recess (81) allows for a larger axial gap (CR1) between the piston (35, 45) and the thin-walled portion (52, 58). The first recess (81) can be easily formed on the piston (35, 45) after it has been formed by laser processing or roller burnishing. The rotary compressor (1) according to this first embodiment can suppress seizure between the piston (35, 45) and the front head (50) and rear head (56) with simple processing.

[0112] In the rotary compressor (1) according to this embodiment 1, the first recess (81) is configured as a stepped portion. Therefore, the first recess (81) can be easily formed on the pistons (35, 45). The rotary compressor (1) according to this embodiment 1 can suppress seizure between the pistons (35, 45) and the front head (50) and rear head (56) with simple processing.

[0113] In the rotary compressor (1) according to this embodiment 1, the first recess (81) is positioned such that, in an axial view, it includes a 90° range on the discharge port (51, 57) side, with respect to the center line (CL) of the blade (38, 48) passing through the centers (DC1, DC2) of the eccentric portion (91, 92). The first recess (81) is limited to a range in which it can be located near the discharge port (51, 57) on the piston (35, 45). This makes it possible to narrow the range in which the axial gap between the piston (35, 45) and the front head (50) and rear head (56) becomes large. The rotary compressor (1) according to this embodiment 1 can suppress seizure between the piston (35, 45) and the front head (50) and rear head (56) while increasing the compression efficiency.

[0114] In the rotary compressor (1) according to this first embodiment, the first recess (81) is located only on the side (35a, 45b) of the piston (35, 45) that is closer to the discharge port (51, 57) out of both sides (35a, 35b, 45a, 45b) in the axial direction. This makes it possible to narrow the range in which the axial gap between the piston (35, 45) and the front head (50) and rear head (56) becomes large. The rotary compressor (1) according to this first embodiment can suppress seizure between the piston (35, 45) and the front head (50) and rear head (56) while increasing the compression efficiency.

[0115] In the rotary compressor (1) according to this first embodiment, the axial gap between the surface (38b) of the first blade (38) closest to the first discharge port (51) and the front head (50) is larger than the axial gap (CR2) between the second region (78) of the first piston (35) and the second region (78) of the front head (50). Also, the axial gap between the surface (48c) of the second blade (48) closest to the second discharge port (57) and the rear head (56) is larger than the axial gap (CR2) between the second region (78) of the second piston (45) and the second region (78) of the rear head (56). As a result, even if the blades (38, 48) undergo thermal expansion due to high temperature and high pressure refrigerant, seizure between the blades (38, 48) and the front head (50) and rear head (56) can be suppressed.

[0116] In the rotary compressor (1) according to this first embodiment, the surface (38b) of the first blade (38) closest to the first discharge port (51) is flush with the bottom surface of the first recess (81) of the first piston (35). Also, the surface (48c) of the second blade (48) closest to the second discharge port (57) is flush with the bottom surface of the first recess (81) of the second piston (45). The machining of the blades (38, 48) can be performed simultaneously with the process of forming the first recess (81) in the pistons (35, 45). The rotary compressor (1) according to this first embodiment can suppress seizure between the first piston (35) and the front head (50) and between the second piston (45) and the rear head (56) with simple machining.

[0117] In the rotary compressor (1) according to this embodiment 1, the refrigerant is carbon dioxide. Compared to other refrigerants, carbon dioxide tends to cause high pressure near the discharge ports (51, 57) outside the cylinder chambers (S1, S2). Therefore, when carbon dioxide is used, the thin-walled sections (52, 58) tend to deform toward the cylinder chambers (S1, S2). Even when using carbon dioxide, the rotary compressor (1) according to this embodiment 1 can suppress seizure between the pistons (35, 45) and the front head (50) and rear head (56).

[0118] (7) Variant The above-described embodiment 1 may also be modified as follows. In the following description, we will primarily explain the differences from the above-described embodiment 1.

[0119] (7-1) Variation 1 In the rotary compressor (1) of the modified example 1, the configuration of the pistons (35, 45) and blades (38, 48) differs from that of the embodiment 1.

[0120] The pistons (35, 45) in Modification 1 have a first recess (81), as well as a second recess (82) on the axial surfaces (35b, 45a) of the pistons (35, 45) that are furthest from the discharge ports (51, 57). Figure 12 shows the first piston (35) and the first blade (38) in Modification 1. The second recess (82) of the first piston (35) is located on the lower surface (35b) of the first piston (35). Although not shown in the figure, the second recess (82) of the second piston (45) is located on the upper surface (45a) of the second piston (45).

[0121] The second recess (82) is located in a position that overlaps with the first recess (81) in an axial view. Specifically, the second recess (82) includes the first region (77) and, like the first recess (81), is located so as to include a 90° range on the second discharge port (57) side, with respect to the center line of the second blade (48) passing through the center (DC2) of the second eccentric portion (92). The range of the second recess (82) does not necessarily have to be the same as that of the first recess (81). The second recess (82) may be located in a different range from the first recess (81) as long as it overlaps with the first recess (81) in an axial view.

[0122] The second recess (82) is recessed on the opposite side of the axial direction from the first recess (81). The depth of the second recess (82) is the same as the depth of the first recess (81). The depth of the second recess (82) does not necessarily have to be the same as the first recess (81); it may be shallower or deeper than the first recess (81).

[0123] The blades (38, 48) have a thinner axial thickness compared to the embodiment 1. As shown in Figure 12, the upper surface (38b) of the first blade (38) is flush with the bottom surface of the first recess (81), and the lower surface (38c) of the first blade (38) is flush with the lower surface of the bottom of the second recess (82).

[0124] Although not shown in the diagram, the second piston (45) and second blade (48) are configured in an inverted manner compared to the first piston (35) and first blade (38). Specifically, the second recess (82) of the second piston (45) is located on the upper surface (45a) of the second piston (45). The upper surface (48b) of the second blade (48) is flush with the bottom surface of the second recess (82), and the lower surface (48c) of the second blade (48) is flush with the lower surface of the bottom of the first recess (81).

[0125] When the thermal expansion of the pistons (35, 45) is large, there is a risk that the discharge side portion of the pistons (35, 45) and the middle plate (55) may seize up. In the rotary compressor (1) according to this modified example 1, since the pistons (35, 45) have a second recess (82), seizure between the discharge side portion of the pistons (35, 45) and the middle plate (55) can be suppressed.

[0126] Furthermore, as in this modified example 1, if the second recess (82) is formed in the same position and shape as the first recess (81), the pistons (35, 45) will have a symmetrical shape in the axial direction. Therefore, when arranging the pistons (35, 45) in the cylinders (31, 41), it is no longer necessary to consider the vertical orientation. The rotary compressor (1) according to this modified example 1 can be easily manufactured.

[0127] (7-2) Variation 2 In the rotary compressor (1) of the modified example 2, the configuration of the pistons (35, 45) and blades (38, 48) differs from that of the embodiment 1.

[0128] Figures 13 and 14 show the first piston (35) and first blade (38) according to Modification 1. In Modification 2, the bottom surface of the first recess (81) of the first piston (35) is inclined. When the first piston (35) is at top dead center, the first recess (81) is deeper in the circumferential direction closer to the first discharge port (51) than the portion of the second region (78) of the first piston (35). The outer edge of the first recess (81) is deeper than the inner edge of the first piston (35). When the first piston (35) is at top dead center, the portion overlapping with the first discharge port (51) in an axial view is a valley (81a). The depth of the first recess (81) at the deepest point of the valley (81a) is 2 μm to 20 μm, preferably 2 μm to 10 μm, and more preferably 2 μm to 5 μm.

[0129] As shown in Figure 13, the upper surface (38b) of the first blade (38) is an inclined surface. In the radial direction, the upper surface (38b) of the first blade (38) is deeper relative to the intake side portion of the first piston (35) as it approaches the connecting portion (38a) between the first piston (35) and the first blade (38). No step is formed between the first blade (38) and the first piston (35) at the connecting portion (38a).

[0130] Although not shown in the diagram, the first recess (81) and second blade (48) of the second piston (45) have inclined surfaces, similar to the first recess (81) and first blade (38) of the first piston (35). The first recess (81) and second blade (48) of the second piston (45) are configured inverted vertically compared to the first recess (81) and first blade (38) of the first piston (35).

[0131] When the thin-walled sections (52, 58) deform toward the cylinder chambers (S1, S2) with the connection points between the thin-walled sections (52, 58) and other parts as pivot points, the amount of displacement is greater in the thin-walled sections (52, 58) closer to the discharge ports (51, 57). For this reason, the parts of the thin-walled sections (52, 58) around the discharge ports (51, 57) are particularly prone to seizure. In the rotary compressor (1) according to this modified example 1, the first recess (81) is deeper relative to the second region (78) of the piston (35, 45) in the circumferential direction closer to the discharge ports (51, 57). In the rotary compressor (1) according to this modified example 1, even if the parts of the thin-walled sections (52, 58) around the discharge ports (51, 57) are displaced significantly, seizure between the piston (35, 45) and the front head (50) and rear head (56) can be suppressed.

[0132] Furthermore, the pistons (35, 45) are closer to the discharge space (72, 76) as they are radially outward, making them more susceptible to deformation due to thermal expansion. In the rotary compressor (1) according to this modified example 1, the first recess (81) is deeper at the outer edge of the first piston (35) than at the inner edge. In the rotary compressor (1) according to this modified example 1, seizure between the pistons (35, 45) and the front head (50) and rear head (56) can be suppressed even if the deformation due to thermal expansion of the pistons (35, 45) is large.

[0133] Furthermore, the blades (38, 48) are closer to the discharge ports (51, 57) as they are closer to the connection points (38a, 48a) with the pistons (35, 45). In the rotary compressor (1) according to this modified example 1, the surfaces (38b, 48c) of the blades (38, 48) that are closer to the discharge ports (51, 57) are deeper in the radial direction than the second region (78) of the pistons (35, 45) as they are closer to the connection points (38a, 48a) between the pistons (35, 45) and the blades (38, 48). In the rotary compressor (1) according to this modified example 1, seizure between the blades (38, 48) and the front head (50) and rear head (56) can be suppressed even if the area around the discharge ports (51, 57) in the thin-walled section (52, 58) is greatly displaced.

[0134] (7-3) Modification 3 In the rotary compressor (1) of the modified example 3, the configuration of the pistons (35, 45) and blades (38, 48) differs from that of the embodiment 1.

[0135] Figure 15 shows the first piston (35) and first blade (38) according to Modification 3. In Modification 3, the first piston (35) has a narrower range of the first recess (81) in the circumferential direction compared to Embodiment 1. Specifically, of the first recess (81), the portion located at the connection point (38a) between the first piston (35) and the first blade (38) is located only on the half on the first discharge port (51) side (left side in Figure 15). In other words, the suction side half of the connection point (38a) does not have the first recess (81). Also, of the first blade (38), only the half of the upper surface (38b) from the center line (CL) to the first discharge port (51) is recessed relative to the second region (78) of the first piston (35). The upper surface (38b) of the first blade (38) is flush with the portion of the second region (78) of the first piston (35), with respect to the center line (CL) and the first intake port (17).

[0136] Although not shown in the diagram, the first recess (81) and second blade (48) of the second piston (45) are configured in an inverted manner compared to the first recess (81) and first blade (38) of the first piston (35).

[0137] In the rotary compressor (1) according to this modified example 3, the range in which the axial clearance between the pistons (35, 45) and blades (38, 48) and the front head (50) and rear head (56) becomes large can be narrowed. The rotary compressor (1) according to this modified example 3 can suppress seizure between the pistons (35, 45) and the front head (50) and rear head (56) while increasing the compression efficiency.

[0138] (7-4) Modification 4 In the rotary compressor (1) of the modified example 4, the configuration of the pistons (35, 45) differs from that of the embodiment 1.

[0139] Figure 16 shows the first piston (35) and first blade (38) according to Modification 4. The first piston (35) according to Modification 4 has a third recess (83) located in a different part of the circumferential direction of the first piston (35) from the first recess (81), and having a recessed axial surface. In the example of Figure 16, the third recess (83) is located on the upper surface (35a) of the first piston (35). The third recess (83) is located in a different part of the first piston (35) from the first region (77) and the second region (78). The third recess (83) is located in the first piston (35) at a circumferential angle of 180° relative to the first recess (81). The circumferential range of the third recess (83) is narrower than that of the first recess (81). The depth of the third recess (83) is the same as that of the first recess (81). The third recess (83) may be located on the lower surface (35b) of the first piston (35). The depth of the third recess (83) does not necessarily have to be the same as that of the first recess (81); it may be shallower or deeper than the first recess (81).

[0140] Although not shown in the diagram, the third recess (83) of the second piston (45) is configured in an inverted manner compared to the third recess (83) of the first piston (35).

[0141] In addition to the pressure difference inside and outside the cylinder chambers (S1, S2) and the thermal expansion of the pistons (35, 45), the axial force and thermal deformation of the through bolts (B) can also cause the axial clearance between the pistons (35, 45) and the front head (50), middle plate (55), and rear head (56) to narrow. By arranging the third recess (83), the rotary compressor (1) according to this modified example 4 can suppress seizure between the pistons (35, 45) and the front head (50), middle plate (55), and rear head (56) in areas other than near the discharge ports (51, 57).

[0142] (7-5) Variation 5 In the rotary compressor (1) of the modified example 5, the configuration of the pistons (35, 45) differs from that of the embodiment 1.

[0143] Figure 17 shows the first piston (35) and first blade (38) according to Modification 5. The first piston (35) according to Modification 5 has an inclined surface (84) between the first recess (81) and the upper surface (35a). The inclined surface (84) is formed at both ends of the first recess (81) in the circumferential direction of the first piston (35).

[0144] As shown in Figure 18, the inclined surface (84) is an inclined curved surface that is convex upwards in the portion near the top surface (35a) and convex downwards in the portion near the first recess (81). The inclined surface (84) and the top surface (35a) are smoothly continuous. The inclined surface (84) and the first recess (81) are smoothly continuous. "Smoothly continuous" means that they are continuous without any steps or are tangentially continuous.

[0145] Although not shown in the diagram, the inclined surface (84) of the second piston (45) is configured to be inverted vertically compared to the inclined surface (84) of the first piston (35).

[0146] In addition to the pressure difference between the inside and outside of the cylinder chambers (S1, S2) and the thermal expansion of the pistons (35, 45), the axial force and thermal deformation of the through bolts (B) can also cause the axial gap between the pistons (35, 45) and the front head (50), middle plate (55), and rear head (56) to narrow. By arranging inclined surfaces (84) at both ends of the first recess (81), it is possible to suppress the boundary between the first recess (81) and the upper surface (35a) from catching on the front head (50), middle plate (55), and rear head (56) when the pistons (35, 45) rotate. Therefore, the rotary compressor (1) according to this modified example 5 can suppress seizure between the pistons (35, 45) and the front head (50), middle plate (55), and rear head (56) even in areas other than near the discharge ports (51, 57).

[0147] Furthermore, the inclined surface (84) may not be an inclined curved surface, but rather formed by one or more inclined planes. If the inclined surface (84) is an inclined plane, it does not have to be smoothly continuous with the upper surface (35a) and the first recess (81). Also, even if the inclined surface (84) is an inclined curved surface, it does not have to be smoothly continuous with the upper surface (35a) and the first recess (81), and there may be a slight angle at the boundary between the inclined surface (84) and the upper surface (35a) and the boundary between the inclined surface (84) and the first recess (81).

[0148] <Embodiment 2> Embodiment 2 of this disclosure will be described in detail with reference to the drawings. In the following description, parts common to Embodiment 1 will be denoted by the same reference numerals, and their detailed descriptions will be omitted.

[0149] (8) Front head, rear head The rotary compressor (201) according to this second embodiment differs from the configuration of the front head (250) and rear head (256) in the first embodiment. Specifically, in this second embodiment, the front head (250) and rear head (256) are provided with a fourth recess (252a, 258a) on the side facing the cylinder chambers (S1, S2). In this second embodiment, the pistons (235, 245) do not have the first recess.

[0150] As shown in Figure 19, the front head (250) has a fourth recess (252a) in the first region (277) that is recessed compared to the second region (278). The fourth recess (252a) of the front head (250) is located only in the area surrounding the first discharge port (251) in the first region (277).

[0151] The formation of a fourth recess (252a) in the front head (250) increases the axial clearance between the first piston (235) and the front head (250) in the first region (277). Specifically, when the first piston (235) is at bottom dead center, the axial clearance (CR3) between the portion of the first region (277) of the first piston (235) and the portion of the first region (277) of the front head (250) is greater than the axial clearance (CR4) between the portion of the second region (278) of the first piston (235) and the portion of the second region (278) of the front head (250).

[0152] As shown in Figure 20, the rear head (256) on the side facing the second cylinder chamber (S2) has a fourth recess (258a) in the first region (277) that is recessed compared to the second region (278). The fourth recess (258a) of the rear head (256) is located in the portion surrounding the second discharge port (257) in the first region (277).

[0153] The formation of a fourth recess (258a) in the rear head (256) increases the axial clearance between the second piston (245) and the rear head (256) in the first region (277). Specifically, when the second piston (245) is at bottom dead center, the axial clearance (CR5) between the portion of the second piston (245) in the first region (277) and the portion of the rear head (256) in the first region (277) is greater than the axial clearance (CR6) between the portion of the second piston (245) in the second region (278) and the portion of the rear head (256) in the second region (278).

[0154] The depth of the fourth recess (252a, 258a) is 2 μm to 20 μm, preferably 2 μm to 10 μm, and more preferably 2 μm to 5 μm. The fourth recess (252a, 258a) slightly thins a portion of the thin-walled portion (252, 258). However, the area of ​​the fourth recess (252a, 258a) in the thin-walled portion (252, 258) is limited to the first region (277) of the thin-walled portion (252, 258). Furthermore, the depth of the fourth recess (252a, 258a) is at most about 20 μm. Therefore, the fourth recess (252a, 258a) has almost no effect on making the thin-walled portion (252, 258) more susceptible to deformation.

[0155] (9) Effects of Embodiment 2 In this second embodiment, the first region (277) of the front head (250) has a fourth recess (252a) on the side facing the first cylinder chamber (S1) that is recessed compared to the second region (278) of the front head (250). Similarly, the first region (277) of the rear head (256) has a fourth recess (258a) on the side facing the second cylinder chamber (S2) that is recessed compared to the second region (278) of the rear head (256). This allows for larger axial clearances in the first region (277) between the front head (250) and the first piston (235), and between the rear head (256) and the second piston (245). Even if deformation of the thin-walled sections (252, 258) occurs when the outside of the cylinder chambers (S1, S2) becomes more pressure than the inside, and thermal expansion of the pistons (235, 245) occurs, it is possible to prevent the axial gap between the first piston (235) and the front head (250), and the axial gap between the second piston (245) and the rear head (256) from becoming zero. Therefore, the rotary compressor (201) according to this second embodiment can prevent seizure between the pistons (235, 245) and the front head (250) and the rear head (256).

[0156] In this second embodiment, the fourth recesses (252a, 258a) in the front head (250) and rear head (256) are located only in the area surrounding the discharge ports (251, 257) in the first region (277). This allows the rotary compressor (201) to narrow the range in which the gap between the pistons (235, 245) and the front head (250) and rear head (256) becomes large. The rotary compressor (201) according to this second embodiment can suppress seizure between the pistons (235, 245) and the front head (250) and rear head (256) while increasing compression efficiency.

[0157] <Other Embodiments> As shown in Figure 21, the compression mechanism (330) of the rotary compressor (301) may have two suction pipes, a first suction pipe (314a) and a second suction pipe (314b). In Figure 21, the first suction pipe (314a) is connected to the first suction port (317) of the first cylinder (331). The second suction pipe (314b) is connected to the second suction port (318) of the second cylinder (341). In the example shown in Figure 21, there is no suction passage as in Embodiment 1, and the suction ports (317, 318) are directly connected to the suction pipes (314a, 34b). The first suction pipe (314a) may be located in the front head (350), and the second suction pipe (314b) may be located in the rear head (356). One or both of the first inhalation tube (314a) and the second inhalation tube (314b) may be located on the middle plate (355). In these cases, an inhalation passage must be provided.

[0158] As shown in Figure 22, the compression mechanism (430) of the rotary compressor (401) may be a single cylinder having one piston (35) and one eccentric part (91). In the example shown in Figure 22, the intake pipe (414) is inserted into the insertion hole (419) of the rear head (456). The intake pipe (414) is connected to the intake port (417) via an intake passage (416) formed in the rear head (456) and the cylinder (431). The intake pipe (414) may be located in either the front head (450) or the cylinder (431).

[0159] The piston (35) may have all of the first recess (81), the second recess (82), and the third recess (83).

[0160] A first recess (81) may be provided on the piston (35), and a fourth recess (252a, 258a) may be provided on the front head (50, 250) and the rear head (56, 256, 456).

[0161] The axial gap between the surface (38b) of the first blade (38) closest to the first discharge port (51) and the front head (50) may be the same as the axial gap (CR2) between the second region (78,278) of the first piston (35) and the second region (78,278) of the front head (50). Also, the axial gap between the surface (48c) of the second blade (48) closest to the second discharge port (57) and the rear head (56) may be the same as the axial gap (CR2) between the second region (78,278) of the second piston (45) and the second region (78,278) of the rear head (56).

[0162] The compressor (1) may be of the hinge vane type, in which blades separate from the pistons (35, 45) are rotatably fixed to the ends of the pistons (35, 45).

[0163] While embodiments and modifications have been described above, it will be understood that a variety of changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the embodiments, modifications, and other embodiments described above may be combined or substituted as appropriate, as long as they do not impair the functions covered by this disclosure.

[0164] The designations "1st," "2nd," "3rd," etc., mentioned above are used to distinguish between the terms to which these designations are attached, and do not limit the number or order of those terms. [Industrial applicability]

[0165] As described above, this disclosure is useful for rotary compressors. [Explanation of Symbols]

[0166] 1. Rotary Compressor 31. First cylinder 35 First Piston 35a Top surface (the side closest to the discharge port) 35b Bottom surface (the side furthest from the discharge port) 38 First Blade 38a Connecting part 38b Top surface 41. Second Cylinder 45. Second piston 45a Top surface (the side furthest from the discharge port) 45b Bottom surface (the side closest to the discharge port) 48. Second Blade 48a Connecting part 48c bottom surface 50 Front head (closing member) 51 First discharge port 52 1st thin section 55 Middle plate (closing member) 56 Rear head (closing member) 57 Second discharge port 58 2nd thin section 77 First area 78 Second area 81 First recess 82 Second recess 83 Third recess 90° Rotation axis 91 1st eccentric part 92 2nd eccentric part 100 Refrigeration equipment 201 Rotary Compressor 235 First Piston 245 Second piston 250 Front head (closing member) 251 First discharge port 252 1st thin section 256 Rear head (closing member) 257 Second discharge port 258 2nd thin section 252a Fourth recess 258a Fourth recess 277 First area 278 Second area 301 Rotary Compressor 331 First Cylinder 341 Second Cylinder 350 Front head (closing member) 355 Middle plate (closure member) 356 Rear head (closing member) 401 Rotary Compressor 431 Cylinder 450 Front head (closing member) 456 Rear head (closing member) DC1 Center of the first eccentric part DC2 Center of the second eccentric part L1 First line segment L2 Second line segment LC Chuo Line P1 1st point P2 2nd point X: Center of the rotation axis

Claims

1. Cylinders (31, 41, 331, 341, 431) having internal cylinder chambers (S1, S2), Pistons (35, 45, 235, 245) that rotate along the inner surface of the cylinder chambers (S1, S2) without rotating, The rotating shaft (90) that rotates the aforementioned pistons (35, 45, 235, 245), Blades (38, 48) connected to the pistons (35, 45, 235, 245) divide the cylinder chambers (S1, S2) into intake spaces (71, 75) and discharge spaces (72, 76), Intake ports (17, 18, 317, 318, 417) that supply refrigerant to the aforementioned intake space (71, 75), The cylinder chambers (S1, S2) include closing members (50, 56, 250, 256, 350, 355, 356, 450, 456) that close both axial ends of the rotating shaft (90), At the positions of the pistons (35, 45, 235, 245), the rotating shaft (90) includes eccentric portions (91, 92) that are eccentric with respect to the center (X) of the rotating shaft (90). The aforementioned closing members (50, 56, 250, 256, 350, 355, 356, 450, 456) are Discharge ports (51, 57, 251, 257) that communicate with the discharge spaces (72, 76) and discharge compressed refrigerant from the discharge spaces (72, 76), Includes a thin-walled portion (52, 58, 252, 258) formed in a range including the periphery of the discharge port (51, 57, 251, 257) and having a thinner axial thickness than the other parts of the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456), In axial view, The first line segment (L1) is defined as the line segment connecting the first point (P1) closest to the bottom dead center of the piston (35, 45, 235, 245) among the intersection points where the outer edge of the thin-walled portion (52, 58, 252, 258) and the inner edge of the cylinder (31, 41) intersect, and the center (X) of the rotation axis (90). The second line segment (L2) is defined as the line segment connecting the second point (P2) closest to the bottom dead center of the piston (35, 45, 235, 245) among the intersection points where the intake port (17, 18, 317, 318, 417) and the inner edge of the cylinder (31, 41) intersect, and the center (X) of the rotation axis (90). When the pistons (35, 45, 235, 245) are at bottom dead center, the region between the blades (38, 48) and the first line segment (L1) that overlaps with the cylinder chambers (S1, S2) is defined as the first region (77, 277). When the pistons (35, 45, 235, 245) are at bottom dead center, the region between the blades (38, 48) and the second line segment (L2) that overlaps with the cylinder chambers (S1, S2) is defined as the second region (78, 278). A rotary compressor in which, when the piston (35, 45, 235, 245) is at its bottom dead center, the gap (CR1) between the portion of the first region (77, 277) at the outer edge of the piston (35, 45, 235, 245) and the portion of the first region (77, 277) of the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456) is larger than the gap (CR2) between the portion of the second region (78, 278) of the piston (35, 45, 235, 245) and the portion of the second region (78, 278).

2. In the rotary compressor according to claim 1, A rotary compressor wherein the portion of the piston (35, 45, 235, 245) in the first region (77, 277) has a first recess (81) in which the axial surface is concave compared to the portion of the piston (35, 45, 235, 245) in the second region (78, 278).

3. In the rotary compressor according to claim 2, The first recess (81) is positioned in an axial view of a rotary compressor, with reference to the center line (CL) of the blade (38, 48) passing through the centers (DC1, DC2) of the eccentric portions (91, 92), and including a 90° range on the discharge port (51, 57, 251, 257) side, with the centers (DC1, DC2) of the eccentric portions (91, 92) as the center.

4. In the rotary compressor according to claim 2 or 3, A rotary compressor in which the first recess (81) is located only on the side (35a, 45b) of the piston (35, 45, 235, 245) that is closer to the discharge port (51, 57, 251, 257) out of the axial sides (35a, 35b, 45a, 45b).

5. In the rotary compressor according to claim 2 or 3, The first recess (81) is located on the side (35a, 45b) of the piston (35, 45, 235, 245) that is closer to the discharge port (51, 57, 251, 257) among the axial sides (35a, 35b, 45a, 45b), A rotary compressor in which, of the two axial surfaces (35a, 35b, 45a, 45b) of the piston (35, 45, 235, 245), the surfaces (35b, 45a) furthest from the discharge ports (51, 57, 251, 257) have a second recess in an axial view that overlaps with the first recess (81) and is recessed on the opposite side from the first recess (81).

6. In the rotary compressor according to claim 2 or 3, A rotary compressor wherein the first recess (81) is deeper than the suction side portion of the piston (35, 45, 235, 245) in the circumferential direction of the piston (35, 45, 235, 245) when the piston (35, 45, 235, 245) is at top dead center, with the portion closer to the discharge port (51, 57, 251, 257) being deeper.

7. In the rotary compressor according to claim 2 or 3, A rotary compressor in which the pistons (35, 45, 235, 245) are located in a different part of the circumferential direction of the pistons (35, 45, 235, 245) from the first recess (81), and have a third recess (83) whose axial surface is recessed.

8. In the rotary compressor according to claim 2 or 3, A rotary compressor in which the gap between at least a portion of the blades (38, 48) and the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456) is greater than the gap (CR2) between the suction-side portion of the piston (35, 45, 235, 245) and the suction-side portion of the occluding members (50, 56, 250, 256, 350, 355, 356, 450, 456).

9. In the rotary compressor according to claim 8, A rotary compressor in which at least a portion of the blades (38, 48) is located on the discharge port (51, 57, 251, 257) side and has a recessed axial surface (38b, 48c) compared to the portion on the suction port (17, 18, 317, 318, 417) side.

10. In the rotary compressor according to claim 8, A rotary compressor in which at least a portion of the blades (38, 48) is deeper than the suction side portion of the pistons (35, 45, 235, 245) in the portion closer to the connection between the pistons (35, 45, 235, 245) and the blades (38, 48).

11. In the rotary compressor according to claim 1, The portion of the first region (77, 277) of the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456) has a fourth recess (252a, 258a) on the side facing the cylinder chamber (S1, S2) that is recessed compared to the portion of the second region (78, 278) of the closing member (50, 56, 250, 256, 350, 355, 356, 450, 456), A rotary compressor in which the fourth recesses (252a, 258a) are located only around the discharge ports (51, 57, 251, 257) in the closing members (50, 56, 250, 256, 350, 355, 356, 450, 456).

12. In the rotary compressor according to any one of claims 1 to 3, The rotary compressor uses carbon dioxide as the refrigerant.

13. A refrigeration system comprising a rotary compressor (1,201,301,401) according to any one of claims 1 to 3.

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