Rotary compressor and refrigeration device provided with same

Abstract

An injection flow path (61) communicating with an injection pipe (9c) is formed in a first cylinder (31, 41), a middle plate (55), and a second cylinder (31, 41). The injection flow path (61) includes: a first flow path (61a) connected to the injection pipe (9c); a second flow path (61b, 61c) branching from the first flow path (61a) and communicating with a first cylinder chamber (S1, S2); and a third flow path (61b, 61c) branching from the first flow path (61a) and communicating with the second cylinder chamber (S1, S2).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a rotary compressor and a refrigeration apparatus including the rotary compressor. The rotary compressor is a compressor that compresses gas in a compression chamber formed in a cylinder by eccentrically rotating a roller in the cylinder. The rotary compressor generally has a vane for partitioning a compression chamber. There are various types of rotary compressors, such as a so-called rolling piston compressor in which a roller eccentrically rotates while a vane separated from the roller abuts on the roller, a so-called swing compressor in which a vane integrally formed with the roller swings with the eccentric rotation of the roller, and a so-called hinge vane type compressor in which the roller eccentrically rotates with a tip of the vane rotatably fitted in a recess of an outer peripheral surface of the roller.BACKGROUND ART

[0002] Patent Document 1 discloses a rotary compressor including a first cylinder with a first cylinder chamber, and a second cylinder with a second cylinder chamber. In this rotary compressor, the first cylinder has a first flow path communicating with the first cylinder chamber, and the second cylinder has a second flow path communicating with the second cylinder chamber. A first injection pipe for discharging the refrigerant from the gas-liquid separator is connected to the first flow path. A second injection pipe for discharging the refrigerant from the gas-liquid separator is connected to the second flow path.CITATION LISTPATENT DOCUMENT

[0003] PATENT DOCUMENT 1: Japanese Translation of PCT International Application, No. 2015-531846SUMMARY OF THE INVENTIONTECHNICAL PROBLEMS

[0004] In general, there is a demand for lowering the height of the rotary compressor to hardly cause refrigerant leakage. In Patent Document 1, however, the injection pipes are directly connected to both the first flow path in the first cylinder and the second flow path in the second cylinder. Both the first cylinder and the second cylinder thus need to be thick enough to directly connect the injection pipes, hindering the lowering of the height of the rotary compressor sufficiently.

[0005] It is an object of the present disclosure to lower the height of a rotary compressor.SOLUTION TO THE PROBLEMS

[0006] A first aspect of the present disclosure is directed to a rotary compressor to which an injection pipe (9c) is connected. The rotary compressor includes: a casing (10); a first cylinder (31, 41) disposed inside the casing (10) and having a first cylinder chamber (S1, S2); a first piston (34, 44) configured to eccentrically rotate in the first cylinder chamber (S1, S2); a second cylinder (31, 41) disposed inside the casing (10) and having a second cylinder chamber (S1, S2); a second piston (34, 44) configured to eccentrically rotate in the second cylinder chamber (S1, S2); a shaft (90) coupled to the first piston (34, 44) and the second piston (34, 44); a middle plate (55) disposed between the first cylinder (31, 41) and the second cylinder (31, 41); a first bearing (50, 56) disposed on a side of the first cylinder (31, 41) opposite to the middle plate (55) and pivotally supporting the shaft (90); and a second bearing (50, 56) disposed on a side of the second cylinder (31, 41) opposite to the middle plate (55) and pivotally supporting the shaft (90), an injection flow path (61) communicating with the injection pipe (9c) is formed in the first cylinder (31, 41), the middle plate (55), and the second cylinder (31, 41), and the injection flow path (61) includes: a first flow path (61a) connected to the injection pipe (9c); a second flow path (61b, 61c) branching from the first flow path (61a) and communicating with the first cylinder chamber (S1, S2); and a third flow path (61b, 61c) branching from the first flow path (61a) and communicating with the second cylinder chamber (S1, S2).

[0007] In the first aspect, the first flow path (61a) directly connected to the injection pipe (9c) is branched into the second flow path (61b, 61c) and the third flow path (61b, 61c). There is thus no need to directly connect the injection pipe (9c) to each cylinder (31, 41). Accordingly, the height of the rotary compressor (1) can be lowered as compared with the case where the injection pipe (9c) is directly connected to each cylinder (31, 41).

[0008] A second aspect of the present disclosure is an embodiment of the first aspect. In the second aspect, the second flow path (61b, 61c) is provided with a first reed valve (62, 66) to move up and down at an end thereof in an axial direction of the shaft (90). The third flow path (61b, 61c) is provided with a second reed valve (62, 66) to move up and down at an end thereof in the axial direction.

[0009] In the second aspect, the first reed valve (62, 66) can introduce the refrigerant into the first cylinder chamber (S1, S2). The second reed valve (62, 66) can introduce the refrigerant into the second cylinder chamber (S1, S2).

[0010] A third aspect of the present disclosure is an embodiment of the first or second aspect. In the third aspect, the second flow path (61b, 61c) or the third flow path (61b, 61c) has a fourth flow path (61d) extending in the axial direction of the shaft (90) and penetrating the middle plate (55). The fourth flow path (61d) has an average flow path diameter larger than or equal to that of the first flow path (61a).

[0011] In the third aspect, the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1, S2) and the second cylinder chamber (S1, S2) can be reduced as compared to a case where the fourth flow path (61d) has a smaller average flow path diameter than that of the first flow path (61a).

[0012] A fourth aspect of the present disclosure is an embodiment of any one of the first to third aspects. In the fourth aspect, a sum of flow path areas of the second flow path (61b, 61c) and the third flow path (61b, 61c) is larger than or equal to a flow path area of the first flow path (61a).

[0013] In the fourth aspect, the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1, S2) and the second cylinder chamber (S1, S2) can be reduced as compared to a case where the sum of the flow path areas of the second flow path (61b, 61c) and the third flow path (61b, 61c) is smaller than the flow path area of the first flow path (61a).

[0014] A fifth aspect of the present disclosure is an embodiment of any one of the first to fourth aspects. In the fifth aspect, the rotary compressor further includes: an injection muffler (80) connected to the injection pipe (9c), the axial direction of the shaft (90) is a vertical direction, the first bearing (56) is a lower bearing, the second bearing (50) is an upper bearing, part of the first flow path (61a) is formed in the first bearing (56), and a lower end of the injection muffler (80) is located below a lower end of the second bearing (50).

[0015] In the fifth aspect, the part of the first flow path (61a) is formed in the lower bearing (56), and the lower end of the injection muffler (80) is disposed below the lower end of the second bearing (50). This configuration can lower the center of gravity of the rotary compressor (1).

[0016] A sixth aspect of the present disclosure is an embodiment of the second aspect. In the sixth aspect, the first cylinder (31, 41) has an injection opening (31a, 41a) open at one end in the axial direction and a bolt insertion hole (31c, 41c) penetrating the first cylinder (31, 41) in the axial direction, the first reed valve (62, 66) is attached to the first cylinder (31, 41) by a bolt (65, 67) so as to open and close the injection opening (31a, 41a), the first reed valve (62, 66) has a fastening hole (62a, 66a) in a surface facing the first cylinder (31, 41), and the bolt (65, 67) is inserted into the bolt insertion hole (31c, 41c) and has a distal end fastened to the fastening hole (62a, 66a).

[0017] In the sixth aspect, the first cylinder (31, 41) has the bolt insertion hole (31c, 41c) that houses the portion, such as the head of the bolt (65, 67), other than the distal end of the bolt (65, 67). This configuration easily reduces the thickness of the first reed valve (62, 66) and the volume (dead volume) of the space connected to the first cylinder chamber (S1, S2), as compared to the case where the first reed valve (62, 66) has the bolt insertion hole (31c, 41c).

[0018] A seventh aspect of the present disclosure is an embodiment of any one of the first to sixth aspects. In the seventh aspect, the first cylinder (31, 41) has a vane housing hole (33, 43) configured to house a vane (36, 46) of the first piston (34, 44). An end of the second flow path (61b, 61c) on a side of the first cylinder chamber (S1, S2) is inclined toward the vane housing hole (33, 43) in a radially inward direction of the first cylinder (31, 41).

[0019] In the seventh aspect, the end of the second flow path (61b, 61c) on the side of the first cylinder chamber (S1, S2) is inclined toward the vane housing hole (33, 43) in a radially inward direction of the first cylinder (31, 41). If the second flow path (61b, 61c) and a suction port (17, 18) for sucking the refrigerant are disposed on both sides of the straight line connecting the vane housing hole (33, 43) and the center of the first cylinder (31, 41), the end of the second flow path (61b, 61c) on the side of the first cylinder chamber (S1, S2) and the suction port (17, 18) can be spaced apart from each other in the circumferential direction of a suction space (71, 75). This easily reduces the backflow of the refrigerant to the second flow path (61b, 61c).

[0020] An eighth aspect of the present disclosure is an embodiment of the seventh aspect. In the eighth aspect, the first cylinder (31, 41) has the vane housing hole (33, 43) configured to house the vane (36, 46) of the first piston (34, 44), the first cylinder (31, 41) has, in one axial end surface thereof, a recess (31a, 41a) extending while being inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31, 41), the recess (31a, 41a) has, in a bottom surface thereof, an injection opening (31b, 41b), the second flow path (61b, 61c) includes a lateral flow path (31e, 41e) extending in the radial direction, and a communication path (31f, 41f) coupling the lateral flow path (31e, 41e) and the injection opening (31b, 41b) in the axial direction, the recess (31a, 41a) houses a first reed valve (62, 66), and an extending direction of the lateral flow path (31e, 41e) and an extending direction of the recess (31a, 41a) are offset from each other by 5 degrees or more.

[0021] In the eighth aspect, the recess (31a, 41a) is inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31, 41). If the injection opening (31b, 41b) and the suction port (17, 18) for sucking the refrigerant are disposed on both sides of the straight line connecting the vane housing hole (33, 43) and the center of the first cylinder (31, 41), the injection opening (31b, 41b) and the suction port (17, 18) can be spaced apart from each other in the circumferential direction of the suction space (71, 75). This easily reduces the backflow of the refrigerant to the second flow path (61b, 61c).

[0022] A ninth aspect of the present disclosure is an embodiment of any one of the first to eighth aspects. In the ninth aspect, the first bearing (50, 56) has a discharge port (51, 57) for discharging a refrigerant from the first cylinder chamber (S1, S2), the first cylinder (31, 41) has, in an inner peripheral surface thereof, a discharge cutout (37, 47) recessed toward an outer circumference so that an inner space of the discharge cutout (37, 47) overlaps the discharge port (51, 57) in the axial direction of the shaft (90), and the second flow path (61b, 61c) communicates with the inner space of the discharge cutout (37, 47).

[0023] In the ninth aspect, the discharge cutout (37, 47) is formed, reducing a rapid change in the cross-sectional area of the discharge flow path. Accordingly, the flow path resistance of the discharge flow path can be reduced.

[0024] A tenth aspect is an embodiment of any one of the first to ninth aspects. In the tenth aspect, the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1) and the second cylinder chamber (S2) is CO2.

[0025] In the tenth aspect, the refrigerant leakage tends to occur using CO2 with a relatively large pressure difference as the refrigerant, and thus can be reduced by lowering the height of the compressor (1).

[0026] An eleventh aspect of the present disclosure is directed to a refrigeration apparatus (100). The refrigeration apparatus (100) includes the rotary compressor (1) of any one of the first to tenth aspects.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] [FIG. 1] FIG. 1 is a piping system diagram of a refrigeration apparatus including a rotary compressor according to an embodiment. [FIG. 2] FIG. 2 is a plan view of the rotary compressor. [FIG. 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [FIG. 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 7. [FIG. 5] FIG. 5 is a cross-sectional view taken along line V-V in FIG. 7. [FIG. 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 2. [FIG. 7] FIG. 7 is an enlarged view of section VII in FIG. 6. [FIG. 8] FIG. 8 is a partial cross-sectional view taken along line VIII-VIII in FIG. 2. [FIG. 9] FIG. 9 shows an operation of a compression mechanism. DESCRIPTION OF EMBODIMENTS

[0028] Embodiments of the present disclosure will be described in detail below with reference to the drawings. The present disclosure is not limited to the embodiments shown below, and various changes can be made within the scope without departing from the technical concept of the present disclosure. Since each of the drawings is intended to illustrate the present disclosure conceptually, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for the sake of ease of understanding. In the following description, unless otherwise specified, an "axial direction" indicates a direction in which a shaft extends, a "radial direction" indicates a direction radially extending from the shaft, and a "circumferential direction " indicates a circumferential direction about the shaft. The terms "upper / above / top" and "lower / below / bottom" refer to directions when a rotary compressor (1) is viewed from the front. Some drawings may be illustrated without hatching to facilitate understanding.(1) Refrigeration Apparatus

[0029] FIG. 1 shows a refrigeration apparatus (100) including the rotary compressor (1) according to this first embodiment. Hereinafter, the rotary compressor (1) may be simply referred to as a compressor (1). The refrigeration apparatus (100) is an air conditioner that conditions air in an indoor space, for example. The refrigeration apparatus (100) has an outdoor unit (7) disposed in an outdoor space and an indoor unit (8) disposed in the indoor space. The outdoor unit (7) includes the compressor (1), an accumulator (2), a four-way switching valve (3), an outdoor heat exchanger (4a), an economizer heat exchanger (4b), and an expansion valve (5). The indoor unit (8) includes an indoor heat exchanger (6). The outdoor unit (7) and the indoor unit (8) are connected via a connection pipe (9a) to form a refrigerant circuit (9).

[0030] The compressor (1) compresses low-pressure gas refrigerant into high-pressure gas refrigerant. The compressor (1) is driven by a compressor motor. Part of intermediate-pressure refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) is supplied to the compressor (1) to perform intermediate injection. The intermediate pressure is a predetermined pressure between the pressure (low pressure) of gas refrigerant sucked into the compressor (1) and the pressure (high pressure) of gas refrigerant discharged from the compressor (1). The refrigerant is not particularly limited, but is, for example, carbon dioxide (CO2).

[0031] The four-way switching valve (3) switches a connection state of an internal pipe of the outdoor unit (7). When the refrigeration apparatus (100) performs a cooling operation, the four-way switching valve (3) is in the connection state indicated by broken lines in FIG. 1. When the refrigeration apparatus (100) performs a heating operation, the four-way switching valve (3) is in the connection state indicated by solid lines in FIG. 1.

[0032] The outdoor heat exchanger (4a) exchanges heat between outdoor air and the refrigerant circulating in the refrigerant circuit (9). The outdoor heat exchanger (4a) has a refrigerant flow path through which the refrigerant flows, and a heat transfer fin in contact with the outdoor air. The outdoor heat exchanger (4a) functions as a radiator (condenser) for the refrigerant in the cooling operation, and as a heat absorber (evaporator) for the refrigerant in the heating operation.

[0033] The expansion valve (5) is an electric valve or an electromagnetic valve having a variable opening degree. The expansion valve (5) decompresses the refrigerant flowing through the internal pipe of the outdoor unit (7). The expansion valve (5) controls the flow rate of the refrigerant flowing through the internal pipe of the outdoor unit (7).

[0034] The accumulator (2) is disposed in a pipe on the suction side of the compressor (1). The accumulator (2) separates a gas-liquid mixed refrigerant flowing through the refrigerant circuit into gas refrigerant and liquid refrigerant, and stores the liquid refrigerant. The gas refrigerant separated in the accumulator (2) is sent to a suction port of the compressor (1).

[0035] The economizer heat exchanger (4b) is disposed between the outdoor heat exchanger (4a) and the expansion valve (5). The economizer heat exchanger (4b) exchanges heat between the refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) and the refrigerant flowing through an economizer pipe (9b). The economizer pipe (9b) is a pipe branched from the refrigerant circuit (9) between the economizer heat exchanger (4b) and the expansion valve (5) and connected to an injection pipe (9c) (described later). An economizer valve (9d) is attached to the economizer pipe (9b). The refrigerant flowing through the economizer pipe (9b) is decompressed 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 having exchanged heat in the economizer heat exchanger (4b) are, as the intermediate-pressure refrigerant, supplied to the injection pipe (9c).

[0036] The refrigeration apparatus (100) includes the refrigerant circuit (9). The compressor (1), the four-way switching valve (3), the outdoor heat exchanger (4a), the expansion valve (5), the indoor heat exchanger (6), and the economizer heat exchanger (4b) are connected to the refrigerant circuit (9). The refrigerant flows through the refrigerant circuit (9) to perform a refrigeration cycle.

[0037] The refrigeration apparatus (100) performs the heating operation and the cooling operation by switching the four-way switching valve (3). In the cooling operation, a first refrigeration cycle is performed. Specifically, in the connection state indicated by the broken lines in FIG. 1, the indoor heat exchanger (6) functions as an evaporator, and the outdoor heat exchanger (4a) functions as a radiator. In the heating operation, a second refrigeration cycle is performed. Specifically, in the connection state indicated by the solid lines in FIG. 1, the indoor heat exchanger (6) functions as a radiator, and the outdoor heat exchanger (4a) functions as an evaporator.(2) Rotary Compressor

[0038] FIGS. 2 to 8 show the compressor (1). As illustrated in FIGS. 3 and 6, the compressor (1) includes a casing (10), an electric motor (20), and a compression mechanism (30). The electric motor (20) and the compression mechanism (30) are housed in the casing (10). The compressor (1) is of a so-called high-pressure dome type in which the refrigerant compressed in the compression mechanism (30) is discharged into an internal space (R) of the casing (10) so that the internal space (R) has a high pressure.(2-1) Rotary Compressor

[0039] The casing (10) is vertically long. Specifically, the casing (10) includes a cylindrical barrel (11) extending in the up-down direction, an upper lid (12) closing the upper end of the barrel (11), and a lower lid (13) closing the lower end of the barrel (11). A discharge pipe (15) is inserted into an upper portion of the barrel (11). A suction pipe (14) is disposed in a lower portion of the barrel (11).(2-2) Electric Motor

[0040] The electric motor (20) is housed in the casing (10). The electric motor (20) drives the compression mechanism (30). The electric motor (20) is disposed above a mounting plate (54). The electric motor (20) has a tubular stator (21) along the inner peripheral surface of the barrel (11), and a rotor (22) disposed inside the stator (21).(2-3) Shaft

[0041] A shaft (90) is disposed to extend in the vertical direction in the casing (10). That is, the axial direction of the shaft (90) is the vertical direction. The shaft (90) is driven by the electric motor (20). An upper portion of the shaft (90) is coupled to the rotor (22) of the electric motor (20).

[0042] A lower portion of the shaft (90) has, in this order from the top to the 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 formed integrally.

[0043] The first eccentric portion (91) and the second eccentric portion (92) are eccentric with respect to the axis of the shaft (90). The first eccentric portion (91) and the second eccentric portion (92) have larger diameters than those of 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 shaft (90) is different from that of the second eccentric portion (92) with respect to the rotation center axis of the shaft (90) by 180°.

[0044] The intermediate shaft portion (90b) is disposed between the first eccentric portion (91) and the second eccentric portion (92). The intermediate shaft portion (90b) couples the first eccentric portion (91) and the second eccentric portion (92).(2-4) Compression Mechanism

[0045] The compression mechanism (30) is located in the casing (10). The compression mechanism (30) compresses the sucked refrigerant, and discharges the compressed refrigerant to the internal space (R) of the casing (10). The compression mechanism (30) is fixed to the mounting plate (54) fixed to the inner peripheral surface of the barrel (11). Specifically, the compression mechanism (30) is disposed on the lower surface of the mounting plate (54). The compression mechanism (30) has two cylinders. The compression mechanism (30) includes the shaft (90), a front head (50) as an upper bearing (or second bearing), a first cylinder (31), a first piston (34), a middle plate (55), a second cylinder (41), a second piston (44), and a rear head (56) as a lower bearing (or first bearing).

[0046] As shown in FIGS. 6 and 7, an injection flow path (61) is formed in the first cylinder (31), the middle plate (55), the second cylinder (41), and the rear head (56). The injection flow path (61) communicates with the injection pipe (9c). As shown in FIG. 6, an injection muffler (80) is connected to the injection pipe (9c). The lower end of the injection muffler (80) is located below the lower end of the front head (50).

[0047] As shown in the enlarged view in FIG. 7, the injection flow path (61) includes: a first flow path (61a) connected to the injection pipe (9c); a second flow path (61b) branching from the first flow path (61a) and communicating with a first cylinder chamber (S1) (described later); and a third flow path (61c) branching from the first flow path (61a) and communicating with a second cylinder chamber (S2) (described later). The injection pipe (9c) is connected to the first flow path (61a) by being inserted from the outer side in the radial direction. The sum of the flow path areas of the second flow path (61b) and the third flow path (61c) is larger than or equal to the flow path area of the first flow path (61a). The second flow path (61b) has a fourth flow path (61d) extending in the axial direction of the shaft (90) and penetrating the middle plate (55). The fourth flow path (61d) has an average flow path diameter larger than or equal to that of the first flow path (61a).(2-4-1) Cylinder

[0048] The first cylinder (31) and the second cylinder (41) are thick disk-shaped members. As shown in FIGS. 4 and 5 particularly, the cylinders (31, 41) have cylinder bores (32, 42), respectively. Each cylinder bore (32, 42) is a circular hole penetrating the corresponding cylinder (31, 41) in the thickness direction thereof. The cylinder bore (32, 42) is formed in a center portion of the cylinder (31, 41). The first cylinder bore (32) of the first cylinder (31) houses the first piston (34). The second cylinder bore (42) of the second cylinder (41) houses the second piston (44).

[0049] In the first cylinder (31), a first cylinder chamber (S1) is formed between the wall surface of the cylinder bore (32) and the first piston (34). In the second cylinder (41), a second cylinder chamber (S2) is formed between the wall surface of the cylinder bore (42) and the second piston (44).

[0050] Both the cylinders (31, 41) have vane housing holes (33, 43) extending from the inner peripheral surfaces of the respective cylinders (31, 41) (i.e., the outer edges of the cylinder bores (32, 42)) outward in the radial direction of the cylinders (31, 41), respectively. These vane housing holes (33, 43) penetrate the corresponding cylinders (31, 41), respectively, in the thickness direction.

[0051] The first cylinder (31) has a first passage (16a) which is part of a suction 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 disposed on the right of the vane housing hole (33) in FIG. 4. The second cylinder (41) has a second passage (16b) which is part of the suction passage (16). The second passage (16b) penetrates the second cylinder (41) in the thickness direction thereof. The second passage (16b) is disposed on the right of a vane housing hole (43) in FIG. 5.

[0052] The cylinder (31, 41) has a suction port (17, 18) extending from the suction passage (16) toward the cylinder chamber (S1, S2). The first suction port (17) of the first cylinder (31) extends from the first passage (16a) toward the first cylinder chamber (S1). As shown in FIG. 4, the first suction port (17) of the first cylinder (31) extends at a point apart from the vane housing hole (33) by an angle of 30 degrees or less clockwise as viewed from above. The second suction port (18) of the second cylinder (41) extends from the second passage (16b) toward the second cylinder chamber (S2). As shown in FIG. 5, the second suction port (18) of the second cylinder (41) extends at a point apart from the vane housing hole (43) by an angle of 30 degrees or less clockwise as viewed from above. The suction port (17, 18) extends toward the cylinder chamber (S1, S2) to be closer to the vane housing hole (33, 43) than the suction passage (16) is, as viewed in the axial direction.

[0053] The first cylinder (31) has, in the lower end surface (one axial end surface) thereof, a first recess (31a) being in an elongated shape in plan view and extending in the radially inward direction of the first cylinder (31) while being inclined toward the vane housing hole (33). The first recess (31a) has, at a radially inner end of the bottom surface thereof, a first injection opening (31b) opening in one axial direction. The first recess (31a) has, at a radially outer end of the bottom surface thereof, a first bolt insertion hole (31c) penetrating in the axial direction.

[0054] Between the first cylinder chamber (S1) and the first recess (31a) in the lower end surface (i.e., one axial end surface) of the first cylinder (31), a first communication groove (31d) thinner than the first recess (31a) is formed to extend in the longitudinal direction of the first recess (31a). This first communication groove (31d) corresponds to the end of the second flow path (61b) on the side of the first cylinder chamber (S1). This first communication groove (31d), that is, the end of the second flow path (61b) on the side of the first cylinder chamber (S1) is also inclined toward the vane housing hole (33) in the radially inward direction of the first cylinder (31).

[0055] As shown only in FIG. 4, on the inner peripheral surface of the first cylinder (31), a first discharge cutout (37) recessed toward the outer peripheral side so as to form an arc shape when viewed from above is formed around an end of the second flow path (61b) on the side of the first cylinder chamber (S1). The first communication groove (31d), that is, the second flow path (61b) communicates with the inner space of the first discharge cutout (37).

[0056] As shown in FIG. 7, the first cylinder (31) includes: the upper end of the fourth flow path (61d); a first lateral flow path (31e) extending in the radially inward direction from the upper end of the fourth flow path (61d); and a first communication path (31f) extending downward from the radially inner end of the first lateral flow path (31e) to connect the first lateral flow path (31e) and the first injection opening (31b) in the axial direction. The first lateral flow path (31e) and the first communication path (31f) are part of the second flow path (61b). As shown in FIG. 4, the first lateral flow path (31e) extends at a point apart from the vane housing hole (33) by an angle of 30 degrees or less counterclockwise (i.e., in the direction opposite to the first suction port (17)) as viewed from above. The extending direction of first lateral flow path (31e) and the extending direction of the first recess (31a) are offset from each other by about 30 degrees. That is, the angle α between the first lateral flow path (31e) and the first recess (31a) is about 30 degrees. By offsetting the extending direction of the first lateral flow path (31e) and the extending direction of the first recess (31a) by 5 degrees or more, that is, by setting the angle α to 5 degrees or more, the first bolt insertion hole (31c) can be less likely to interfere with the first lateral flow path (31e).

[0057] The first recess (31a) of the first cylinder (31) houses a first reed valve (62) in an elongated shape with the longitudinal direction of the first reed valve (62) extending along the longitudinal direction of the first recess (31a). At one longitudinal end of the surface of the first reed valve (62) that faces the bottom surface of the first recess (31a) of the first cylinder (31), a fastening hole (62a) is formed.

[0058] As shown in FIG. 8, the first reed valve (62) includes a valve body (63) and a valve retainer (64) facing the valve body (63) from the side opposite to the first injection opening (31b). The valve body (63) is a thin plate-shaped member that is elongated and flat. The valve body (63) is made of metal such as spring steel or iron. The valve body (63) is flexible.

[0059] The valve retainer (64) is in an elongated plate-like shape corresponding to the shape of the valve body (63). The radially inner end of the surface of the valve retainer (64) on the side of the valve body (63) is inclined to be away from the bottom surface of the first recess (31a) as extending in the radially inward direction.

[0060] The fastening hole (62a) penetrates both the valve body (63) and the valve retainer (64).

[0061] The first reed valve (62) is attached to the first cylinder (31) by inserting a bolt (65) into the first bolt insertion hole (31c) of the first cylinder (31) and fastening the distal end of the bolt (65) to the fastening hole (62a) of the valve retainer (64). The first bolt insertion hole (31c) of the first cylinder (31) houses the portion of the bolt (65) other than the distal end, such as the head of the bolt (65). In this state, the first reed valve (62) can open and close the first injection opening (31b) by moving one end (i.e., the end opposite to the fastening hole (62a)) thereof up and down in the axial direction of the shaft (90). In this manner, the first reed valve (62) is provided in the second flow path (61b).

[0062] The second cylinder (41) has, in the upper end surface (one axial end surface) thereof, a second recess (41a) being in an elongated shape in plan view and extending in the radially inward direction of the second cylinder (41) while being inclined toward the vane housing hole (43). The second recess (41a) has, at the radially inner end of the bottom surface thereof, a second injection opening (41b) opening in the one axial direction. The second recess (41a) has, at the radially outer end of the bottom surface thereof, a second bolt insertion hole (41c) penetrating in the axial direction.

[0063] Between the second cylinder chamber (S2) and the second recess (41a) in the lower end surface (i.e., one axial end surface) of the second cylinder (41), a second communication groove (41d) thinner than the second recess (41a) extends in the longitudinal direction of the second recess (41a). This second communication groove (41d) forms the end of the third flow path (61c) on the side of the second cylinder chamber (S2). This second communication groove (41d), that is, the end of the third flow path (61c) on the side of the second cylinder chamber (S2) is also inclined toward the vane housing hole (43) in the radially inward direction of the second cylinder (41).

[0064] On the inner peripheral surface of the second cylinder (41), a second discharge cutout (47) recessed toward the outer peripheral side so as to form an arc shape when viewed from above is formed around an end of the third flow path (61c) on the side of the second cylinder chamber (S2). The second communication groove (41d), that is, the third flow path (61c) communicates with the inner space of the second discharge cutout (47).

[0065] As shown in FIG. 7, the second cylinder (41) includes: the lower end of the fourth flow path (61d); a second lateral flow path (41e) extending in the radially inward direction from the lower end of the fourth flow path (61d); and a second communication path (41f) extending upward from the radially inner end of the second lateral flow path (41e) to connect the second lateral flow path (41e) and the second injection opening (41b) in the axial direction. The second lateral flow path (41e) and the second communication path (41f) are part of the third flow path (61c). As shown in FIG. 5, the second lateral flow path (41e) extends at a point apart from the vane housing hole (43) by an angle of 30 degrees or less counterclockwise (i.e., in the direction opposite to the second suction port (18)) as viewed from above. The extending direction of the second lateral flow path (41e) and the extending direction of the second recess (41a) are offset from each other by about 30 degrees. That is, the angle β between the second lateral flow path (41e) and the second recess (41a) is about 30 degrees. By offsetting the extending direction of the second lateral flow path (41e) and the extending direction of the second recess (41a) by 5 degrees or more, that is, by setting the angle β to 5 degrees or more, the second bolt insertion hole (41c) can be less likely to interfere with the second lateral flow path (41e).

[0066] The second recess (41a) of the second cylinder (41) houses a second reed valve (66) with the same configuration as the first reed valve (62). The second reed valve (66) also has a fastening hole (66a).

[0067] As shown in FIG. 8, the second reed valve (66) is attached to the second cylinder (41) in the same manner as the first reed valve (62) by inserting a bolt (67) into the second bolt insertion hole (41c) of the second cylinder (41) and fastening the distal end of the bolt (67) to the fastening hole (66a) of the second reed valve (66). The second bolt insertion hole (41c) of the second cylinder (41) houses the portion of the bolt (67) other than the distal end, such as the head of the bolt (67). In this state, the second reed valve (66) can open and close the second injection opening (41b) by moving one end (i.e., the end opposite to the fastening hole (66a)) thereof up and down in the axial direction of the shaft (90). In this manner, the second reed valve (66) is provided in the third flow path (61c).(2-4-2) Piston

[0068] The first piston (34) is housed in the first cylinder (31). The first piston (34) eccentrically rotates in the first cylinder chamber (S1). The first piston (34) slides on both the front head (50) and the middle plate (55).

[0069] As shown in FIG. 4, the first piston (34) includes a first piston body (roller) (35) and a first vane (36). The first piston body (35) is formed in an annular shape. The first piston body (35) is formed in a slightly thick cylindrical shape. The first eccentric portion (91) of the shaft (90) is inserted through and coupled to the first piston body (35). The first piston body (35) turns along the inner peripheral surface of the first cylinder chamber (S1) of the first cylinder (31) by rotating the first eccentric portion (91).

[0070] The first vane (36) protrudes integrally from the outer peripheral surface of the first piston body (35). The first vane (36) is housed in the vane housing hole (33) of the first cylinder (31). The first vane (36) is sandwiched from both sides by a bushing (70) fitted into the vane housing hole (33). The first vane (36) is supported by the first cylinder (31) via this bushing (70) to be swingable and movable back and forth. The first vane (36) divides the first cylinder chamber (S1) into a first suction space (71) and a first discharge space (72). The first vane (36) restricts the rotation of the first piston (34) itself when the first piston (34) turns. Accordingly, the first piston (34) does not rotate but turns along the inner surface of the first cylinder chamber (S1).

[0071] The second piston (44) is a member being in the same shape and size and made of the same material as the first piston (34). The first piston (34) and the second piston (44) are arranged in an inverted manner in the up-down direction.

[0072] The second piston (44) is housed in the second cylinder (41). The second piston (44) eccentrically rotates in the second cylinder chamber (S2). The second piston (44) slides on both the rear head (56) and the middle plate (55).

[0073] As shown in FIG. 5, the second piston (44) includes a second piston body (roller) (45) and a second vane (46). The second piston body (45) is formed in an annular shape. The second piston body (45) is formed in a slightly thick cylindrical shape. The second eccentric portion (92) of the shaft (90) is inserted through and coupled to the second piston body (45). The second piston body (45) turns along the inner peripheral surface of the second cylinder chamber (S2) of the second cylinder (41) by rotating the second eccentric portion (92).

[0074] The second vane (46) protrudes integrally from the outer peripheral surface of the second piston body (45). The second vane (46) is housed in the vane housing hole (43) of the second cylinder (41). The second vane (46) is sandwiched from both sides by a bushing (70) fitted into the vane housing hole (43). The second vane (46) is supported by the second cylinder (41) via this bushing (70) to be swingable and movable back and forth. The second vane (46) divides the second cylinder chamber (S2) into a second suction space (75) and a second discharge space (not shown). The second vane (46) restricts the rotation of the second piston (44) itself when the second piston (44) turns. Accordingly, the second piston (44) does not rotate but turns along the inner surface of the second cylinder chamber (S2).(2-4-3) Front Head

[0075] The front head (50) is disposed on the side of the first cylinder (31) opposite to the middle plate (55). The front head (50) closes an end of the first cylinder (31) in the axial direction. Specifically, the front head (50) closes the upper end surface (surface on the electric motor (20) side) of the first cylinder (31). The front head (50) is an example of a closing member of the present disclosure. The front head (50) includes a first body portion (50a) and an upper bearing portion (50b). The first body portion (50a) and the upper bearing portion (50b) are integrally formed.

[0076] The first body portion (50a) is formed in a substantially circular thick plate shape. The lower surface of the first body portion (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 extending from the first body portion (50a) toward the electric motor (20) (upward in FIG. 3). The upper bearing portion (50b) is located in a center portion of the first body portion (50a). The upper bearing portion (50b) rotatably supports the upper shaft portion (90a) of the shaft (90).

[0077] As illustrated in FIG. 8, the first body portion (50a) has a first discharge port (51). The first discharge port (51) penetrates the first body portion (50a) in the thickness direction. The first discharge port (51) allows the internal space (R) and the first discharge space (72) to communicate with each other. As shown in FIG. 4, the first discharge port (51) has an outer peripheral edge overlapped by the arc-shaped edge of the first discharge cutout (37). The first discharge port (51) is overlapped by the inner space of the first discharge cutout (37) in the axial direction of the shaft (90).

[0078] A portion of the first body portion (50a) around the first discharge port (51) is a first thin portion (52) having a smaller thickness than the other portion in the axial direction.

[0079] The first discharge port (51) is provided with a first discharge valve (53) that is a reed valve. The first discharge valve (53) covers the first discharge port (51). The first discharge valve (53) is apart from the first discharge port (51) when the pressure of the refrigerant in the first discharge space (72) of the first cylinder chamber (S1) reaches a predetermined value or more. When the first discharge valve (53) is apart from the first discharge port (51), the refrigerant is discharged from the first discharge space (72) of the first cylinder chamber (S1) through the first discharge port (51) to the internal space (R). The first discharge valve (53) covers the first discharge port (51) again after the refrigerant has been discharged to the internal space (R).(2-4-4) Middle Plate

[0080] The middle plate (55) is disposed between the first cylinder (31) and the second cylinder (41). The middle plate (55) closes an end of the first cylinder (31) in the axial direction and an end of the second cylinder (41) in the axial direction. 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).

[0081] A central hole is formed in a center portion of the middle plate (55) so as to penetrate the middle plate (55) in the axial direction. The intermediate shaft portion (90b) of the shaft (90) is inserted into the central hole.

[0082] As shown in FIG. 3, the middle plate (55) has an intermediate passage (16c) which is part of the suction passage (16). The intermediate passage (16c) penetrates the middle plate (55) in the axial direction. The intermediate passage (16c) allows the first passage (16a) and the second passage (16b) to communicate with each other.

[0083] The fourth flow path (61d) extending in the axial direction of the second flow path (61b) of the injection flow path (61) penetrates the middle plate (55).(2-4-5) Rear Head

[0084] The rear head (56) is disposed on the side of the second cylinder (41) opposite to the middle plate (55). The rear head (56) closes an end of the second cylinder (41) in the axial direction. Specifically, the rear head (56) closes the lower end surface (surface opposite to the electric motor (20)) of the second cylinder (41). The rear head (56) is an example of the closing member of the present disclosure.

[0085] The upper surface of the rear head (56) is in close contact with the lower end surface of the second cylinder (41). The rear head (56) rotatably supports the lower shaft portion (90c) of the shaft (90).

[0086] The rear head (56) has a first insertion hole (19) into which the suction pipe (14) is inserted, and a second insertion hole (60) into which the injection pipe (9c) is inserted. The first insertion hole (19) and the second insertion hole (60) each extend in the radial direction.

[0087] 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 from the tip end of the first insertion hole (19) in the axial direction. An upper end portion of the lower passage (16d) communicates with the second passage (16b).

[0088] The injection flow path (61) extends from the second insertion hole (60). The rear head (56) includes part of the first flow path (61a) of the injection flow path (61).

[0089] As shown in FIGS. 7 and 8, the rear head (56) has a second discharge port (57). The second discharge port (57) penetrates the rear head (56) in the thickness direction. The second discharge port (57) allows the internal space (R) and a second discharge space (not shown) to communicate with each other. As shown in FIG. 5, the outer peripheral edge of the second discharge port (57) is overlapped by the arc-shaped edge of the second discharge cutout (47). The second discharge port (57) is overlapped by the inner space of the second discharge cutout (47) in the axial direction of the shaft (90).

[0090] A portion of the rear head (56) around the second discharge port (57) is a second thin portion (58) having a smaller thickness than the other portion in the axial direction.

[0091] The second discharge port (57) is provided with a second discharge valve (59). The second discharge valve (59) covers the second discharge port (57). The second discharge valve (59) is apart from the second discharge port (57) when the pressure of the refrigerant in the second discharge space (not shown) reaches a predetermined value or more. When the second discharge valve (59) is apart from the second discharge port (57), the refrigerant is discharged from the second discharge space (not shown) through the second discharge port (57) to the internal space (R). The second discharge valve (59) covers the second discharge port (57) again after the refrigerant has been discharged to the internal space (R).(3) Operation

[0092] Now, an operation of the compressor (1) will be described with reference to FIG. 9. An operation of compressing the refrigerant by the first cylinder (31) and the first piston (34) and an operation of compressing the refrigerant by the second cylinder (41) and the second piston (44) are basically the same, except that the phases thereof are different by 180°. In the following description, the operation of compressing the refrigerant by the first cylinder (31) and the first piston (34) will be described in detail, and the description of the operation of compressing the refrigerant by the second cylinder (41) and the second piston (44) will be omitted.

[0093] In the compressor (1), once the electric motor (20) starts to rotate the rotor (22), the shaft (90) rotates and the first eccentric portion (91) rotates eccentrically. As the first eccentric portion (91) rotates eccentrically, the first piston (34) turns along the inner peripheral surface of the first cylinder (31) while restricting the rotation.

[0094] A suction phase of sucking the refrigerant into the first cylinder chamber (S1) will be described. Once the shaft (90) slightly rotates from a state (state (A) in FIG. 9) in which the rotational angle thereof is 0°, the position of contact between the first piston (34) and the first cylinder (31) passes by the inner circumferential end of the first suction port (17). At this time, suction of the refrigerant into the first suction space (71) starts.

[0095] The refrigerant is sucked from the suction pipe (14) via the suction passage (16) and the first suction port (17). As the rotational angle of the shaft (90) increases, the volume of the first suction space (71) gradually increases, and then the amount of refrigerant sucked into the first suction space (71) increases (states (B) to (H) in FIG. 9). This refrigerant suction phase continues until the rotational angle of the shaft (90) reaches 360°, and then shifts to a discharge phase.

[0096] The discharge phase of compressing the refrigerant in the first cylinder chamber (S1) and discharging the compressed refrigerant therefrom will be described. When the shaft (90) slightly rotates from a state (state (A) in FIG. 9) in which the rotational angle thereof is 0°, the position of contact between the first piston (34) and the first cylinder (31) passes by the inner peripheral end of the first suction port (17) again. At this time, confinement of the refrigerant in the first suction space (71) is completed.

[0097] The first suction space (71) connected to the first suction port (17) serves as the first discharge space (72) connected only to the first discharge port (51). From this state, compression of the refrigerant in the first discharge space (72) starts. As the rotational angle of the shaft (90) increases, the volume of the first discharge space (72) decreases, and the pressure of the first discharge space (72) increases. When the pressure of the first discharge space (72) exceeds a predetermined pressure, the first discharge valve (53) opens.

[0098] Once 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) of the casing (10), and is then discharged through the discharge pipe (15) to the outside of the compressor (1). This refrigerant discharge phase continues until the rotational angle of the shaft (90) reaches 360°, and then shifts to the suction phase.

[0099] In this manner, the suction phase and the discharge phase are alternately performed in the first cylinder chamber (S1). In the second cylinder chamber (S2), the suction phase and the discharge phase are alternately performed at a phase different from that in the first cylinder chamber (S1) by 180°. Accordingly, the compressor (1) continuously performs the refrigerant compression operation.

[0100] Here, the intermediate-pressure refrigerant, that is, carbon dioxide (CO2) is injected from the injection flow path (61) into the first cylinder chamber (S1) and the second cylinder chamber (S2) during compression. Specifically, when the pressure in the injection flow path (61) is higher than that in the first cylinder chamber (S1), the intermediate-pressure refrigerant is injected from the injection flow path (61) into the first cylinder chamber (S1). On the other hand, when the pressure in the first cylinder chamber (S1) increases and becomes higher than that in the injection flow path (61), the end of the first reed valve (62) opposite to the fastening hole (62a) in the injection flow path (61) is pressed against the peripheral edge of the first injection opening (31b) to close the injection flow path (61), thereby stopping the supply of the intermediate-pressure refrigerant.

[0101] Similarly, when the pressure in the injection flow path (61) is higher than that in the second cylinder chamber (S2), the intermediate-pressure refrigerant is injected from the injection flow path (61) into the second cylinder chamber (S2). On the other hand, when the pressure in the second cylinder chamber (S2) increases and becomes higher than that in the injection flow path (61), the end of the second reed valve (66) opposite to the fastening hole (66a) in the injection flow path (61) is pressed against the peripheral edge of the second injection opening (41b) to close the injection flow path (61), thereby stopping the supply of the intermediate-pressure refrigerant. In this manner, the rotary compressor (1) increases the compression efficiency by injecting the intermediate-pressure refrigerant.(6) Advantages of Embodiment

[0102] In the rotary compressor (1) according to this embodiment, the first flow path (61a) directly connected to the injection pipe (9c) is branched into the second flow path (61b) and the third flow path (61c). There is thus no need to directly connect the injection pipe (9c) to each of the cylinders (31, 41). Accordingly, the height of the rotary compressor (1) can be lowered as compared with the case where the injection pipe (9c) is directly connected to each of the two cylinders (31, 41). In the present embodiment, since CO2 having a relatively large pressure difference is used as a refrigerant, refrigerant leakage is likely to occur; however, by reducing the height of the compressor (1) in this manner, refrigerant leakage can be suppressed.

[0103] The second flow path (61b) is provided with the first reed valve (62). This first reed valve (62) can introduce the refrigerant into the first cylinder chamber (S1). In addition, the third flow path (61c) is provided with the second reed valve (66). This second reed valve (66) can introduce the refrigerant into the second cylinder chamber (S2).

[0104] The fourth flow path (61d) has an average flow path diameter larger than or equal to that of the first flow path (61a). This can reduce the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1) and the second cylinder chamber (S2) as compared to a case where the fourth flow path (61d) has a smaller average flow path diameter than the first flow path (61a).

[0105] The sum of the flow path areas of the second flow path (61b) and the third flow path (61c) is larger than or equal to the flow path area of the first flow path (61a). This can reduce the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1) and the second cylinder chamber (S2) as compared to a case where the fourth flow path (61d) has a smaller flow path area than the first flow path (61a).

[0106] Part of the first flow path (61a) connected to the injection pipe (9c) is formed in the rear head (56), and the lower end of the injection muffler (80) is disposed below the lower end of the front head (50). This configuration can lower the center of gravity of the compressor (1).

[0107] The first bolt insertion hole (31c) is formed in the first cylinder (31). The first bolt insertion hole (31c) houses the portion of the bolt (65) other than the distal end such as the head of the bolt (65). This configuration easily reduces the thickness of the first reed valve (62) and the volume (dead volume) of the space connected to the first cylinder chamber (S1), as compared to the case where the first reed valve (62) has the first bolt insertion hole (31c). The second bolt insertion hole (41c) is formed in the second cylinder (41). The second bolt insertion hole (41c) houses the portion of the bolt (67) other than the distal end such as the head of the bolt (67). This configuration easily reduces the thickness of the second reed valve (66) and the volume (dead volume) of the space connected to the second cylinder chamber (S2), as compared to the case where the second reed valve (66) has the second bolt insertion hole (41c).

[0108] The second flow path (61b) and the first suction port (17) are disposed on both sides of a straight line connecting the vane housing hole (33) and the center of the first cylinder (31). The end of the second flow path (61b) on the side of the first cylinder chamber (S1) is inclined toward the vane housing hole (33) in the radially inward direction of the first cylinder (31). Accordingly, the end of the second flow path (61b) on the side of the first cylinder chamber (S1) and the first suction port (17) are spaced apart from each other in the circumferential direction of the first suction space (71), which can easily reduce the backflow of the refrigerant to the second flow path (61b).

[0109] Similarly, the third flow path (61c) and the second suction port (18) are disposed on both sides of a straight line connecting the vane housing hole (43) and the center of the second cylinder (41). The end of the third flow path (61c) on the side of the second cylinder chamber (S2) is inclined toward the vane housing hole (43) in the radially inward direction of the second cylinder (41). Accordingly, the end of the third flow path (61c) on the side of the second cylinder chamber (S2) and the second suction port (18) are spaced apart from each other in the circumferential direction of the second suction space (75), which can easily reduce the backflow of the refrigerant to the third flow path (61c).

[0110] The first recess (31a) having the first injection opening (31b) is inclined toward the vane housing hole (33) in the radially inward direction of the first cylinder (31). Accordingly, the first injection opening (31b) and the first suction port (17) are spaced apart from each other in the circumferential direction of the first suction space (71), which can easily reduce the backflow of the refrigerant to the second flow path (61b).

[0111] Similarly, the second recess (41a) having the second injection opening (41b) is inclined toward the vane housing hole (43) in the radially inward direction of the second cylinder (41). Accordingly, the second injection opening (41b) and the second suction port (18) are spaced apart from each other in the circumferential direction of the second suction space (75), which can easily reduce the backflow of the refrigerant to the third flow path (61c).

[0112] The first discharge cutout (37) and the second discharge cutout (47) are formed, thereby reducing a rapid change in the cross-sectional area of the discharge flow path. Accordingly, the flow path resistance of the discharge flow path can be reduced.<Other Embodiments>

[0113] The piston (34, 44) and the vane (36, 46) are not necessarily formed integrally with each other. The piston (34, 44) and the vane (36, 46) may be connected by a hinge.

[0114] In the embodiment described above, both the end of the second flow path (61b) on the side of the first cylinder chamber (S1) and the end of the third flow path (61c) on the side of the second cylinder chamber (S2) are inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31) and the second cylinder (41). However, only one of the end of the second flow path (61b) on the side of the first cylinder chamber (S1) or the end of the third flow path (61c) on the side of the second cylinder chamber (S2) may be inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31) and the second cylinder (41).

[0115] In the embodiment described above, both the first recess (31a) of the first cylinder (31) and the second recess (41a) of the second cylinder (41) are inclined toward the vane housing holes (33, 43) in the radially inward direction of the first cylinder (31) and the second cylinder (41), respectively. However, only one of the first recess (31a) or the second recess (41a) may be inclined toward the corresponding vane housing hole (33, 43) in the radially inward direction of the corresponding one of the first cylinder (31) or the second cylinder (41).

[0116] In the embodiment described above, the rear head (56) has the second insertion hole (60) into which the injection pipe (9c) is inserted, and part of the first flow path (61a) of the injection flow path (61). However, the rear head (56) does not necessarily have the injection flow path (61). One of the first cylinder (31) or the second cylinder (41) may have an insertion hole into which the injection pipe (9c) is inserted, and the entire first flow path (61a) and the entire second flow path (61b). Alternatively, the middle plate (55) may have an insertion hole (60) into which the injection pipe (9c) is inserted, the entire first flow path (61a), and the branching portion into the second flow path (61b) and the third flow path (61c).

[0117] It will be understood that the embodiments and variations described above can be modified with various changes in form and details without departing from the spirit and scope of the claims. The embodiments, the variations thereof, and the other embodiments may be combined and replaced with each other without deteriorating intended functions of the present disclosure.

[0118] The expressions such as "first," "second," "third," and so on described above are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.INDUSTRIAL APPLICABILITY

[0119] As described above, the present disclosure is useful for a rotary compressor and a refrigeration apparatus including the rotary compressor.DESCRIPTION OF REFERENCE CHARACTERS

[0120] 1Rotary Compressor S1First Cylinder Chamber S2Second Cylinder Chamber 9cInjection Pipe 10Casing 31First Cylinder 31aFirst Recess 31bFirst Injection Opening 31cFirst Bolt Insertion Hole 31eFirst Lateral Flow Path 31fFirst Communication Path 33Vane Housing Hole 34First Piston 36First Vane 41Second Cylinder 41aSecond Recess 41bSecond Injection Opening 41cSecond Bolt Insertion Hole 41eSecond Lateral Flow Path 41fSecond Communication Path 43Vane Housing Hole 44Second Piston 46Second Vane 50Front Head (Second Bearing) 51First Discharge Port 55Middle Plate 56Rear Head (First Bearing, Lower Bearing) 57Second Discharge Port 61Injection Flow Path 61aFirst Flow Path 61bSecond Flow Path 61cThird Flow Path 61dFourth Flow Path 62First Reed Valve 62aFastening Hole 65Bolt 66Second Reed Valve 66aFastening Hole 67Bolt 80Injection Muffler 90Shaft 100Refrigeration Apparatus

Examples

Embodiment Construction

[0028]Embodiments of the present disclosure will be described in detail below with reference to the drawings. The present disclosure is not limited to the embodiments shown below, and various changes can be made within the scope without departing from the technical concept of the present disclosure. Since each of the drawings is intended to illustrate the present disclosure conceptually, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for the sake of ease of understanding. In the following description, unless otherwise specified, an "axial direction" indicates a direction in which a shaft extends, a "radial direction" indicates a direction radially extending from the shaft, and a "circumferential direction " indicates a circumferential direction about the shaft. The terms "upper / above / top" and "lower / below / bottom" refer to directions when a rotary compressor (1) is viewed from the front. Some drawings may be illustrated without hatching to facilitate und...

TECHNICAL FIELD

[0001] The present disclosure relates to a rotary compressor and a refrigeration apparatus including the rotary compressor. The rotary compressor is a compressor that compresses gas in a compression chamber formed in a cylinder by eccentrically rotating a roller in the cylinder. The rotary compressor generally has a vane for partitioning a compression chamber. There are various types of rotary compressors, such as a so-called rolling piston compressor in which a roller eccentrically rotates while a vane separated from the roller abuts on the roller, a so-called swing compressor in which a vane integrally formed with the roller swings with the eccentric rotation of the roller, and a so-called hinge vane type compressor in which the roller eccentrically rotates with a tip of the vane rotatably fitted in a recess of an outer peripheral surface of the roller.BACKGROUND ART

[0002] Patent Document 1 discloses a rotary compressor including a first cylinder with a first cylinder chamber, and a second cylinder with a second cylinder chamber. In this rotary compressor, the first cylinder has a first flow path communicating with the first cylinder chamber, and the second cylinder has a second flow path communicating with the second cylinder chamber. A first injection pipe for discharging the refrigerant from the gas-liquid separator is connected to the first flow path. A second injection pipe for discharging the refrigerant from the gas-liquid separator is connected to the second flow path.CITATION LISTPATENT DOCUMENT

[0003] PATENT DOCUMENT 1: Japanese Translation of PCT International Application, No. 2015-531846SUMMARY OF THE INVENTIONTECHNICAL PROBLEMS

[0004] In general, there is a demand for lowering the height of the rotary compressor to hardly cause refrigerant leakage. In Patent Document 1, however, the injection pipes are directly connected to both the first flow path in the first cylinder and the second flow path in the second cylinder. Both the first cylinder and the second cylinder thus need to be thick enough to directly connect the injection pipes, hindering the lowering of the height of the rotary compressor sufficiently.

[0005] It is an object of the present disclosure to lower the height of a rotary compressor.SOLUTION TO THE PROBLEMS

[0006] A first aspect of the present disclosure is directed to a rotary compressor to which an injection pipe (9c) is connected. The rotary compressor includes: a casing (10); a first cylinder (31, 41) disposed inside the casing (10) and having a first cylinder chamber (S1, S2); a first piston (34, 44) configured to eccentrically rotate in the first cylinder chamber (S1, S2); a second cylinder (31, 41) disposed inside the casing (10) and having a second cylinder chamber (S1, S2); a second piston (34, 44) configured to eccentrically rotate in the second cylinder chamber (S1, S2); a shaft (90) coupled to the first piston (34, 44) and the second piston (34, 44); a middle plate (55) disposed between the first cylinder (31, 41) and the second cylinder (31, 41); a first bearing (50, 56) disposed on a side of the first cylinder (31, 41) opposite to the middle plate (55) and pivotally supporting the shaft (90); and a second bearing (50, 56) disposed on a side of the second cylinder (31, 41) opposite to the middle plate (55) and pivotally supporting the shaft (90), an injection flow path (61) communicating with the injection pipe (9c) is formed in the first cylinder (31, 41), the middle plate (55), and the second cylinder (31, 41), and the injection flow path (61) includes: a first flow path (61a) connected to the injection pipe (9c); a second flow path (61b, 61c) branching from the first flow path (61a) and communicating with the first cylinder chamber (S1, S2); and a third flow path (61b, 61c) branching from the first flow path (61a) and communicating with the second cylinder chamber (S1, S2).

[0007] In the first aspect, the first flow path (61a) directly connected to the injection pipe (9c) is branched into the second flow path (61b, 61c) and the third flow path (61b, 61c). There is thus no need to directly connect the injection pipe (9c) to each cylinder (31, 41). Accordingly, the height of the rotary compressor (1) can be lowered as compared with the case where the injection pipe (9c) is directly connected to each cylinder (31, 41).

[0008] A second aspect of the present disclosure is an embodiment of the first aspect. In the second aspect, the second flow path (61b, 61c) is provided with a first reed valve (62, 66) to move up and down at an end thereof in an axial direction of the shaft (90). The third flow path (61b, 61c) is provided with a second reed valve (62, 66) to move up and down at an end thereof in the axial direction.

[0009] In the second aspect, the first reed valve (62, 66) can introduce the refrigerant into the first cylinder chamber (S1, S2). The second reed valve (62, 66) can introduce the refrigerant into the second cylinder chamber (S1, S2).

[0010] A third aspect of the present disclosure is an embodiment of the first or second aspect. In the third aspect, the second flow path (61b, 61c) or the third flow path (61b, 61c) has a fourth flow path (61d) extending in the axial direction of the shaft (90) and penetrating the middle plate (55). The fourth flow path (61d) has an average flow path diameter larger than or equal to that of the first flow path (61a).

[0011] In the third aspect, the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1, S2) and the second cylinder chamber (S1, S2) can be reduced as compared to a case where the fourth flow path (61d) has a smaller average flow path diameter than that of the first flow path (61a).

[0012] A fourth aspect of the present disclosure is an embodiment of any one of the first to third aspects. In the fourth aspect, a sum of flow path areas of the second flow path (61b, 61c) and the third flow path (61b, 61c) is larger than or equal to a flow path area of the first flow path (61a).

[0013] In the fourth aspect, the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1, S2) and the second cylinder chamber (S1, S2) can be reduced as compared to a case where the sum of the flow path areas of the second flow path (61b, 61c) and the third flow path (61b, 61c) is smaller than the flow path area of the first flow path (61a).

[0014] A fifth aspect of the present disclosure is an embodiment of any one of the first to fourth aspects. In the fifth aspect, the rotary compressor further includes: an injection muffler (80) connected to the injection pipe (9c), the axial direction of the shaft (90) is a vertical direction, the first bearing (56) is a lower bearing, the second bearing (50) is an upper bearing, part of the first flow path (61a) is formed in the first bearing (56), and a lower end of the injection muffler (80) is located below a lower end of the second bearing (50).

[0015] In the fifth aspect, the part of the first flow path (61a) is formed in the lower bearing (56), and the lower end of the injection muffler (80) is disposed below the lower end of the second bearing (50). This configuration can lower the center of gravity of the rotary compressor (1).

[0016] A sixth aspect of the present disclosure is an embodiment of the second aspect. In the sixth aspect, the first cylinder (31, 41) has an injection opening (31a, 41a) open at one end in the axial direction and a bolt insertion hole (31c, 41c) penetrating the first cylinder (31, 41) in the axial direction, the first reed valve (62, 66) is attached to the first cylinder (31, 41) by a bolt (65, 67) so as to open and close the injection opening (31a, 41a), the first reed valve (62, 66) has a fastening hole (62a, 66a) in a surface facing the first cylinder (31, 41), and the bolt (65, 67) is inserted into the bolt insertion hole (31c, 41c) and has a distal end fastened to the fastening hole (62a, 66a).

[0017] In the sixth aspect, the first cylinder (31, 41) has the bolt insertion hole (31c, 41c) that houses the portion, such as the head of the bolt (65, 67), other than the distal end of the bolt (65, 67). This configuration easily reduces the thickness of the first reed valve (62, 66) and the volume (dead volume) of the space connected to the first cylinder chamber (S1, S2), as compared to the case where the first reed valve (62, 66) has the bolt insertion hole (31c, 41c).

[0018] A seventh aspect of the present disclosure is an embodiment of any one of the first to sixth aspects. In the seventh aspect, the first cylinder (31, 41) has a vane housing hole (33, 43) configured to house a vane (36, 46) of the first piston (34, 44). An end of the second flow path (61b, 61c) on a side of the first cylinder chamber (S1, S2) is inclined toward the vane housing hole (33, 43) in a radially inward direction of the first cylinder (31, 41).

[0019] In the seventh aspect, the end of the second flow path (61b, 61c) on the side of the first cylinder chamber (S1, S2) is inclined toward the vane housing hole (33, 43) in a radially inward direction of the first cylinder (31, 41). If the second flow path (61b, 61c) and a suction port (17, 18) for sucking the refrigerant are disposed on both sides of the straight line connecting the vane housing hole (33, 43) and the center of the first cylinder (31, 41), the end of the second flow path (61b, 61c) on the side of the first cylinder chamber (S1, S2) and the suction port (17, 18) can be spaced apart from each other in the circumferential direction of a suction space (71, 75). This easily reduces the backflow of the refrigerant to the second flow path (61b, 61c).

[0020] An eighth aspect of the present disclosure is an embodiment of the seventh aspect. In the eighth aspect, the first cylinder (31, 41) has the vane housing hole (33, 43) configured to house the vane (36, 46) of the first piston (34, 44), the first cylinder (31, 41) has, in one axial end surface thereof, a recess (31a, 41a) extending while being inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31, 41), the recess (31a, 41a) has, in a bottom surface thereof, an injection opening (31b, 41b), the second flow path (61b, 61c) includes a lateral flow path (31e, 41e) extending in the radial direction, and a communication path (31f, 41f) coupling the lateral flow path (31e, 41e) and the injection opening (31b, 41b) in the axial direction, the recess (31a, 41a) houses a first reed valve (62, 66), and an extending direction of the lateral flow path (31e, 41e) and an extending direction of the recess (31a, 41a) are offset from each other by 5 degrees or more.

[0021] In the eighth aspect, the recess (31a, 41a) is inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31, 41). If the injection opening (31b, 41b) and the suction port (17, 18) for sucking the refrigerant are disposed on both sides of the straight line connecting the vane housing hole (33, 43) and the center of the first cylinder (31, 41), the injection opening (31b, 41b) and the suction port (17, 18) can be spaced apart from each other in the circumferential direction of the suction space (71, 75). This easily reduces the backflow of the refrigerant to the second flow path (61b, 61c).

[0022] A ninth aspect of the present disclosure is an embodiment of any one of the first to eighth aspects. In the ninth aspect, the first bearing (50, 56) has a discharge port (51, 57) for discharging a refrigerant from the first cylinder chamber (S1, S2), the first cylinder (31, 41) has, in an inner peripheral surface thereof, a discharge cutout (37, 47) recessed toward an outer circumference so that an inner space of the discharge cutout (37, 47) overlaps the discharge port (51, 57) in the axial direction of the shaft (90), and the second flow path (61b, 61c) communicates with the inner space of the discharge cutout (37, 47).

[0023] In the ninth aspect, the discharge cutout (37, 47) is formed, reducing a rapid change in the cross-sectional area of the discharge flow path. Accordingly, the flow path resistance of the discharge flow path can be reduced.

[0024] A tenth aspect is an embodiment of any one of the first to ninth aspects. In the tenth aspect, the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1) and the second cylinder chamber (S2) is CO2.

[0025] In the tenth aspect, the refrigerant leakage tends to occur using CO2 with a relatively large pressure difference as the refrigerant, and thus can be reduced by lowering the height of the compressor (1).

[0026] An eleventh aspect of the present disclosure is directed to a refrigeration apparatus (100). The refrigeration apparatus (100) includes the rotary compressor (1) of any one of the first to tenth aspects.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] [FIG. 1] FIG. 1 is a piping system diagram of a refrigeration apparatus including a rotary compressor according to an embodiment. [FIG. 2] FIG. 2 is a plan view of the rotary compressor. [FIG. 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [FIG. 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 7. [FIG. 5] FIG. 5 is a cross-sectional view taken along line V-V in FIG. 7. [FIG. 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 2. [FIG. 7] FIG. 7 is an enlarged view of section VII in FIG. 6. [FIG. 8] FIG. 8 is a partial cross-sectional view taken along line VIII-VIII in FIG. 2. [FIG. 9] FIG. 9 shows an operation of a compression mechanism. DESCRIPTION OF EMBODIMENTS

[0028] Embodiments of the present disclosure will be described in detail below with reference to the drawings. The present disclosure is not limited to the embodiments shown below, and various changes can be made within the scope without departing from the technical concept of the present disclosure. Since each of the drawings is intended to illustrate the present disclosure conceptually, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for the sake of ease of understanding. In the following description, unless otherwise specified, an "axial direction" indicates a direction in which a shaft extends, a "radial direction" indicates a direction radially extending from the shaft, and a "circumferential direction " indicates a circumferential direction about the shaft. The terms "upper / above / top" and "lower / below / bottom" refer to directions when a rotary compressor (1) is viewed from the front. Some drawings may be illustrated without hatching to facilitate understanding.(1) Refrigeration Apparatus

[0029] FIG. 1 shows a refrigeration apparatus (100) including the rotary compressor (1) according to this first embodiment. Hereinafter, the rotary compressor (1) may be simply referred to as a compressor (1). The refrigeration apparatus (100) is an air conditioner that conditions air in an indoor space, for example. The refrigeration apparatus (100) has an outdoor unit (7) disposed in an outdoor space and an indoor unit (8) disposed in the indoor space. The outdoor unit (7) includes the compressor (1), an accumulator (2), a four-way switching valve (3), an outdoor heat exchanger (4a), an economizer heat exchanger (4b), and an expansion valve (5). The indoor unit (8) includes an indoor heat exchanger (6). The outdoor unit (7) and the indoor unit (8) are connected via a connection pipe (9a) to form a refrigerant circuit (9).

[0030] The compressor (1) compresses low-pressure gas refrigerant into high-pressure gas refrigerant. The compressor (1) is driven by a compressor motor. Part of intermediate-pressure refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) is supplied to the compressor (1) to perform intermediate injection. The intermediate pressure is a predetermined pressure between the pressure (low pressure) of gas refrigerant sucked into the compressor (1) and the pressure (high pressure) of gas refrigerant discharged from the compressor (1). The refrigerant is not particularly limited, but is, for example, carbon dioxide (CO2).

[0031] The four-way switching valve (3) switches a connection state of an internal pipe of the outdoor unit (7). When the refrigeration apparatus (100) performs a cooling operation, the four-way switching valve (3) is in the connection state indicated by broken lines in FIG. 1. When the refrigeration apparatus (100) performs a heating operation, the four-way switching valve (3) is in the connection state indicated by solid lines in FIG. 1.

[0032] The outdoor heat exchanger (4a) exchanges heat between outdoor air and the refrigerant circulating in the refrigerant circuit (9). The outdoor heat exchanger (4a) has a refrigerant flow path through which the refrigerant flows, and a heat transfer fin in contact with the outdoor air. The outdoor heat exchanger (4a) functions as a radiator (condenser) for the refrigerant in the cooling operation, and as a heat absorber (evaporator) for the refrigerant in the heating operation.

[0033] The expansion valve (5) is an electric valve or an electromagnetic valve having a variable opening degree. The expansion valve (5) decompresses the refrigerant flowing through the internal pipe of the outdoor unit (7). The expansion valve (5) controls the flow rate of the refrigerant flowing through the internal pipe of the outdoor unit (7).

[0034] The accumulator (2) is disposed in a pipe on the suction side of the compressor (1). The accumulator (2) separates a gas-liquid mixed refrigerant flowing through the refrigerant circuit into gas refrigerant and liquid refrigerant, and stores the liquid refrigerant. The gas refrigerant separated in the accumulator (2) is sent to a suction port of the compressor (1).

[0035] The economizer heat exchanger (4b) is disposed between the outdoor heat exchanger (4a) and the expansion valve (5). The economizer heat exchanger (4b) exchanges heat between the refrigerant flowing from the outdoor heat exchanger (4a) toward the expansion valve (5) and the refrigerant flowing through an economizer pipe (9b). The economizer pipe (9b) is a pipe branched from the refrigerant circuit (9) between the economizer heat exchanger (4b) and the expansion valve (5) and connected to an injection pipe (9c) (described later). An economizer valve (9d) is attached to the economizer pipe (9b). The refrigerant flowing through the economizer pipe (9b) is decompressed 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 having exchanged heat in the economizer heat exchanger (4b) are, as the intermediate-pressure refrigerant, supplied to the injection pipe (9c).

[0036] The refrigeration apparatus (100) includes the refrigerant circuit (9). The compressor (1), the four-way switching valve (3), the outdoor heat exchanger (4a), the expansion valve (5), the indoor heat exchanger (6), and the economizer heat exchanger (4b) are connected to the refrigerant circuit (9). The refrigerant flows through the refrigerant circuit (9) to perform a refrigeration cycle.

[0037] The refrigeration apparatus (100) performs the heating operation and the cooling operation by switching the four-way switching valve (3). In the cooling operation, a first refrigeration cycle is performed. Specifically, in the connection state indicated by the broken lines in FIG. 1, the indoor heat exchanger (6) functions as an evaporator, and the outdoor heat exchanger (4a) functions as a radiator. In the heating operation, a second refrigeration cycle is performed. Specifically, in the connection state indicated by the solid lines in FIG. 1, the indoor heat exchanger (6) functions as a radiator, and the outdoor heat exchanger (4a) functions as an evaporator.(2) Rotary Compressor

[0038] FIGS. 2 to 8 show the compressor (1). As illustrated in FIGS. 3 and 6, the compressor (1) includes a casing (10), an electric motor (20), and a compression mechanism (30). The electric motor (20) and the compression mechanism (30) are housed in the casing (10). The compressor (1) is of a so-called high-pressure dome type in which the refrigerant compressed in the compression mechanism (30) is discharged into an internal space (R) of the casing (10) so that the internal space (R) has a high pressure.(2-1) Rotary Compressor

[0039] The casing (10) is vertically long. Specifically, the casing (10) includes a cylindrical barrel (11) extending in the up-down direction, an upper lid (12) closing the upper end of the barrel (11), and a lower lid (13) closing the lower end of the barrel (11). A discharge pipe (15) is inserted into an upper portion of the barrel (11). A suction pipe (14) is disposed in a lower portion of the barrel (11).(2-2) Electric Motor

[0040] The electric motor (20) is housed in the casing (10). The electric motor (20) drives the compression mechanism (30). The electric motor (20) is disposed above a mounting plate (54). The electric motor (20) has a tubular stator (21) along the inner peripheral surface of the barrel (11), and a rotor (22) disposed inside the stator (21).(2-3) Shaft

[0041] A shaft (90) is disposed to extend in the vertical direction in the casing (10). That is, the axial direction of the shaft (90) is the vertical direction. The shaft (90) is driven by the electric motor (20). An upper portion of the shaft (90) is coupled to the rotor (22) of the electric motor (20).

[0042] A lower portion of the shaft (90) has, in this order from the top to the 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 formed integrally.

[0043] The first eccentric portion (91) and the second eccentric portion (92) are eccentric with respect to the axis of the shaft (90). The first eccentric portion (91) and the second eccentric portion (92) have larger diameters than those of 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 shaft (90) is different from that of the second eccentric portion (92) with respect to the rotation center axis of the shaft (90) by 180°.

[0044] The intermediate shaft portion (90b) is disposed between the first eccentric portion (91) and the second eccentric portion (92). The intermediate shaft portion (90b) couples the first eccentric portion (91) and the second eccentric portion (92).(2-4) Compression Mechanism

[0045] The compression mechanism (30) is located in the casing (10). The compression mechanism (30) compresses the sucked refrigerant, and discharges the compressed refrigerant to the internal space (R) of the casing (10). The compression mechanism (30) is fixed to the mounting plate (54) fixed to the inner peripheral surface of the barrel (11). Specifically, the compression mechanism (30) is disposed on the lower surface of the mounting plate (54). The compression mechanism (30) has two cylinders. The compression mechanism (30) includes the shaft (90), a front head (50) as an upper bearing (or second bearing), a first cylinder (31), a first piston (34), a middle plate (55), a second cylinder (41), a second piston (44), and a rear head (56) as a lower bearing (or first bearing).

[0046] As shown in FIGS. 6 and 7, an injection flow path (61) is formed in the first cylinder (31), the middle plate (55), the second cylinder (41), and the rear head (56). The injection flow path (61) communicates with the injection pipe (9c). As shown in FIG. 6, an injection muffler (80) is connected to the injection pipe (9c). The lower end of the injection muffler (80) is located below the lower end of the front head (50).

[0047] As shown in the enlarged view in FIG. 7, the injection flow path (61) includes: a first flow path (61a) connected to the injection pipe (9c); a second flow path (61b) branching from the first flow path (61a) and communicating with a first cylinder chamber (S1) (described later); and a third flow path (61c) branching from the first flow path (61a) and communicating with a second cylinder chamber (S2) (described later). The injection pipe (9c) is connected to the first flow path (61a) by being inserted from the outer side in the radial direction. The sum of the flow path areas of the second flow path (61b) and the third flow path (61c) is larger than or equal to the flow path area of the first flow path (61a). The second flow path (61b) has a fourth flow path (61d) extending in the axial direction of the shaft (90) and penetrating the middle plate (55). The fourth flow path (61d) has an average flow path diameter larger than or equal to that of the first flow path (61a).(2-4-1) Cylinder

[0048] The first cylinder (31) and the second cylinder (41) are thick disk-shaped members. As shown in FIGS. 4 and 5 particularly, the cylinders (31, 41) have cylinder bores (32, 42), respectively. Each cylinder bore (32, 42) is a circular hole penetrating the corresponding cylinder (31, 41) in the thickness direction thereof. The cylinder bore (32, 42) is formed in a center portion of the cylinder (31, 41). The first cylinder bore (32) of the first cylinder (31) houses the first piston (34). The second cylinder bore (42) of the second cylinder (41) houses the second piston (44).

[0049] In the first cylinder (31), a first cylinder chamber (S1) is formed between the wall surface of the cylinder bore (32) and the first piston (34). In the second cylinder (41), a second cylinder chamber (S2) is formed between the wall surface of the cylinder bore (42) and the second piston (44).

[0050] Both the cylinders (31, 41) have vane housing holes (33, 43) extending from the inner peripheral surfaces of the respective cylinders (31, 41) (i.e., the outer edges of the cylinder bores (32, 42)) outward in the radial direction of the cylinders (31, 41), respectively. These vane housing holes (33, 43) penetrate the corresponding cylinders (31, 41), respectively, in the thickness direction.

[0051] The first cylinder (31) has a first passage (16a) which is part of a suction 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 disposed on the right of the vane housing hole (33) in FIG. 4. The second cylinder (41) has a second passage (16b) which is part of the suction passage (16). The second passage (16b) penetrates the second cylinder (41) in the thickness direction thereof. The second passage (16b) is disposed on the right of a vane housing hole (43) in FIG. 5.

[0052] The cylinder (31, 41) has a suction port (17, 18) extending from the suction passage (16) toward the cylinder chamber (S1, S2). The first suction port (17) of the first cylinder (31) extends from the first passage (16a) toward the first cylinder chamber (S1). As shown in FIG. 4, the first suction port (17) of the first cylinder (31) extends at a point apart from the vane housing hole (33) by an angle of 30 degrees or less clockwise as viewed from above. The second suction port (18) of the second cylinder (41) extends from the second passage (16b) toward the second cylinder chamber (S2). As shown in FIG. 5, the second suction port (18) of the second cylinder (41) extends at a point apart from the vane housing hole (43) by an angle of 30 degrees or less clockwise as viewed from above. The suction port (17, 18) extends toward the cylinder chamber (S1, S2) to be closer to the vane housing hole (33, 43) than the suction passage (16) is, as viewed in the axial direction.

[0053] The first cylinder (31) has, in the lower end surface (one axial end surface) thereof, a first recess (31a) being in an elongated shape in plan view and extending in the radially inward direction of the first cylinder (31) while being inclined toward the vane housing hole (33). The first recess (31a) has, at a radially inner end of the bottom surface thereof, a first injection opening (31b) opening in one axial direction. The first recess (31a) has, at a radially outer end of the bottom surface thereof, a first bolt insertion hole (31c) penetrating in the axial direction.

[0054] Between the first cylinder chamber (S1) and the first recess (31a) in the lower end surface (i.e., one axial end surface) of the first cylinder (31), a first communication groove (31d) thinner than the first recess (31a) is formed to extend in the longitudinal direction of the first recess (31a). This first communication groove (31d) corresponds to the end of the second flow path (61b) on the side of the first cylinder chamber (S1). This first communication groove (31d), that is, the end of the second flow path (61b) on the side of the first cylinder chamber (S1) is also inclined toward the vane housing hole (33) in the radially inward direction of the first cylinder (31).

[0055] As shown only in FIG. 4, on the inner peripheral surface of the first cylinder (31), a first discharge cutout (37) recessed toward the outer peripheral side so as to form an arc shape when viewed from above is formed around an end of the second flow path (61b) on the side of the first cylinder chamber (S1). The first communication groove (31d), that is, the second flow path (61b) communicates with the inner space of the first discharge cutout (37).

[0056] As shown in FIG. 7, the first cylinder (31) includes: the upper end of the fourth flow path (61d); a first lateral flow path (31e) extending in the radially inward direction from the upper end of the fourth flow path (61d); and a first communication path (31f) extending downward from the radially inner end of the first lateral flow path (31e) to connect the first lateral flow path (31e) and the first injection opening (31b) in the axial direction. The first lateral flow path (31e) and the first communication path (31f) are part of the second flow path (61b). As shown in FIG. 4, the first lateral flow path (31e) extends at a point apart from the vane housing hole (33) by an angle of 30 degrees or less counterclockwise (i.e., in the direction opposite to the first suction port (17)) as viewed from above. The extending direction of first lateral flow path (31e) and the extending direction of the first recess (31a) are offset from each other by about 30 degrees. That is, the angle α between the first lateral flow path (31e) and the first recess (31a) is about 30 degrees. By offsetting the extending direction of the first lateral flow path (31e) and the extending direction of the first recess (31a) by 5 degrees or more, that is, by setting the angle α to 5 degrees or more, the first bolt insertion hole (31c) can be less likely to interfere with the first lateral flow path (31e).

[0057] The first recess (31a) of the first cylinder (31) houses a first reed valve (62) in an elongated shape with the longitudinal direction of the first reed valve (62) extending along the longitudinal direction of the first recess (31a). At one longitudinal end of the surface of the first reed valve (62) that faces the bottom surface of the first recess (31a) of the first cylinder (31), a fastening hole (62a) is formed.

[0058] As shown in FIG. 8, the first reed valve (62) includes a valve body (63) and a valve retainer (64) facing the valve body (63) from the side opposite to the first injection opening (31b). The valve body (63) is a thin plate-shaped member that is elongated and flat. The valve body (63) is made of metal such as spring steel or iron. The valve body (63) is flexible.

[0059] The valve retainer (64) is in an elongated plate-like shape corresponding to the shape of the valve body (63). The radially inner end of the surface of the valve retainer (64) on the side of the valve body (63) is inclined to be away from the bottom surface of the first recess (31a) as extending in the radially inward direction.

[0060] The fastening hole (62a) penetrates both the valve body (63) and the valve retainer (64).

[0061] The first reed valve (62) is attached to the first cylinder (31) by inserting a bolt (65) into the first bolt insertion hole (31c) of the first cylinder (31) and fastening the distal end of the bolt (65) to the fastening hole (62a) of the valve retainer (64). The first bolt insertion hole (31c) of the first cylinder (31) houses the portion of the bolt (65) other than the distal end, such as the head of the bolt (65). In this state, the first reed valve (62) can open and close the first injection opening (31b) by moving one end (i.e., the end opposite to the fastening hole (62a)) thereof up and down in the axial direction of the shaft (90). In this manner, the first reed valve (62) is provided in the second flow path (61b).

[0062] The second cylinder (41) has, in the upper end surface (one axial end surface) thereof, a second recess (41a) being in an elongated shape in plan view and extending in the radially inward direction of the second cylinder (41) while being inclined toward the vane housing hole (43). The second recess (41a) has, at the radially inner end of the bottom surface thereof, a second injection opening (41b) opening in the one axial direction. The second recess (41a) has, at the radially outer end of the bottom surface thereof, a second bolt insertion hole (41c) penetrating in the axial direction.

[0063] Between the second cylinder chamber (S2) and the second recess (41a) in the lower end surface (i.e., one axial end surface) of the second cylinder (41), a second communication groove (41d) thinner than the second recess (41a) extends in the longitudinal direction of the second recess (41a). This second communication groove (41d) forms the end of the third flow path (61c) on the side of the second cylinder chamber (S2). This second communication groove (41d), that is, the end of the third flow path (61c) on the side of the second cylinder chamber (S2) is also inclined toward the vane housing hole (43) in the radially inward direction of the second cylinder (41).

[0064] On the inner peripheral surface of the second cylinder (41), a second discharge cutout (47) recessed toward the outer peripheral side so as to form an arc shape when viewed from above is formed around an end of the third flow path (61c) on the side of the second cylinder chamber (S2). The second communication groove (41d), that is, the third flow path (61c) communicates with the inner space of the second discharge cutout (47).

[0065] As shown in FIG. 7, the second cylinder (41) includes: the lower end of the fourth flow path (61d); a second lateral flow path (41e) extending in the radially inward direction from the lower end of the fourth flow path (61d); and a second communication path (41f) extending upward from the radially inner end of the second lateral flow path (41e) to connect the second lateral flow path (41e) and the second injection opening (41b) in the axial direction. The second lateral flow path (41e) and the second communication path (41f) are part of the third flow path (61c). As shown in FIG. 5, the second lateral flow path (41e) extends at a point apart from the vane housing hole (43) by an angle of 30 degrees or less counterclockwise (i.e., in the direction opposite to the second suction port (18)) as viewed from above. The extending direction of the second lateral flow path (41e) and the extending direction of the second recess (41a) are offset from each other by about 30 degrees. That is, the angle β between the second lateral flow path (41e) and the second recess (41a) is about 30 degrees. By offsetting the extending direction of the second lateral flow path (41e) and the extending direction of the second recess (41a) by 5 degrees or more, that is, by setting the angle β to 5 degrees or more, the second bolt insertion hole (41c) can be less likely to interfere with the second lateral flow path (41e).

[0066] The second recess (41a) of the second cylinder (41) houses a second reed valve (66) with the same configuration as the first reed valve (62). The second reed valve (66) also has a fastening hole (66a).

[0067] As shown in FIG. 8, the second reed valve (66) is attached to the second cylinder (41) in the same manner as the first reed valve (62) by inserting a bolt (67) into the second bolt insertion hole (41c) of the second cylinder (41) and fastening the distal end of the bolt (67) to the fastening hole (66a) of the second reed valve (66). The second bolt insertion hole (41c) of the second cylinder (41) houses the portion of the bolt (67) other than the distal end, such as the head of the bolt (67). In this state, the second reed valve (66) can open and close the second injection opening (41b) by moving one end (i.e., the end opposite to the fastening hole (66a)) thereof up and down in the axial direction of the shaft (90). In this manner, the second reed valve (66) is provided in the third flow path (61c).(2-4-2) Piston

[0068] The first piston (34) is housed in the first cylinder (31). The first piston (34) eccentrically rotates in the first cylinder chamber (S1). The first piston (34) slides on both the front head (50) and the middle plate (55).

[0069] As shown in FIG. 4, the first piston (34) includes a first piston body (roller) (35) and a first vane (36). The first piston body (35) is formed in an annular shape. The first piston body (35) is formed in a slightly thick cylindrical shape. The first eccentric portion (91) of the shaft (90) is inserted through and coupled to the first piston body (35). The first piston body (35) turns along the inner peripheral surface of the first cylinder chamber (S1) of the first cylinder (31) by rotating the first eccentric portion (91).

[0070] The first vane (36) protrudes integrally from the outer peripheral surface of the first piston body (35). The first vane (36) is housed in the vane housing hole (33) of the first cylinder (31). The first vane (36) is sandwiched from both sides by a bushing (70) fitted into the vane housing hole (33). The first vane (36) is supported by the first cylinder (31) via this bushing (70) to be swingable and movable back and forth. The first vane (36) divides the first cylinder chamber (S1) into a first suction space (71) and a first discharge space (72). The first vane (36) restricts the rotation of the first piston (34) itself when the first piston (34) turns. Accordingly, the first piston (34) does not rotate but turns along the inner surface of the first cylinder chamber (S1).

[0071] The second piston (44) is a member being in the same shape and size and made of the same material as the first piston (34). The first piston (34) and the second piston (44) are arranged in an inverted manner in the up-down direction.

[0072] The second piston (44) is housed in the second cylinder (41). The second piston (44) eccentrically rotates in the second cylinder chamber (S2). The second piston (44) slides on both the rear head (56) and the middle plate (55).

[0073] As shown in FIG. 5, the second piston (44) includes a second piston body (roller) (45) and a second vane (46). The second piston body (45) is formed in an annular shape. The second piston body (45) is formed in a slightly thick cylindrical shape. The second eccentric portion (92) of the shaft (90) is inserted through and coupled to the second piston body (45). The second piston body (45) turns along the inner peripheral surface of the second cylinder chamber (S2) of the second cylinder (41) by rotating the second eccentric portion (92).

[0074] The second vane (46) protrudes integrally from the outer peripheral surface of the second piston body (45). The second vane (46) is housed in the vane housing hole (43) of the second cylinder (41). The second vane (46) is sandwiched from both sides by a bushing (70) fitted into the vane housing hole (43). The second vane (46) is supported by the second cylinder (41) via this bushing (70) to be swingable and movable back and forth. The second vane (46) divides the second cylinder chamber (S2) into a second suction space (75) and a second discharge space (not shown). The second vane (46) restricts the rotation of the second piston (44) itself when the second piston (44) turns. Accordingly, the second piston (44) does not rotate but turns along the inner surface of the second cylinder chamber (S2).(2-4-3) Front Head

[0075] The front head (50) is disposed on the side of the first cylinder (31) opposite to the middle plate (55). The front head (50) closes an end of the first cylinder (31) in the axial direction. Specifically, the front head (50) closes the upper end surface (surface on the electric motor (20) side) of the first cylinder (31). The front head (50) is an example of a closing member of the present disclosure. The front head (50) includes a first body portion (50a) and an upper bearing portion (50b). The first body portion (50a) and the upper bearing portion (50b) are integrally formed.

[0076] The first body portion (50a) is formed in a substantially circular thick plate shape. The lower surface of the first body portion (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 extending from the first body portion (50a) toward the electric motor (20) (upward in FIG. 3). The upper bearing portion (50b) is located in a center portion of the first body portion (50a). The upper bearing portion (50b) rotatably supports the upper shaft portion (90a) of the shaft (90).

[0077] As illustrated in FIG. 8, the first body portion (50a) has a first discharge port (51). The first discharge port (51) penetrates the first body portion (50a) in the thickness direction. The first discharge port (51) allows the internal space (R) and the first discharge space (72) to communicate with each other. As shown in FIG. 4, the first discharge port (51) has an outer peripheral edge overlapped by the arc-shaped edge of the first discharge cutout (37). The first discharge port (51) is overlapped by the inner space of the first discharge cutout (37) in the axial direction of the shaft (90).

[0078] A portion of the first body portion (50a) around the first discharge port (51) is a first thin portion (52) having a smaller thickness than the other portion in the axial direction.

[0079] The first discharge port (51) is provided with a first discharge valve (53) that is a reed valve. The first discharge valve (53) covers the first discharge port (51). The first discharge valve (53) is apart from the first discharge port (51) when the pressure of the refrigerant in the first discharge space (72) of the first cylinder chamber (S1) reaches a predetermined value or more. When the first discharge valve (53) is apart from the first discharge port (51), the refrigerant is discharged from the first discharge space (72) of the first cylinder chamber (S1) through the first discharge port (51) to the internal space (R). The first discharge valve (53) covers the first discharge port (51) again after the refrigerant has been discharged to the internal space (R).(2-4-4) Middle Plate

[0080] The middle plate (55) is disposed between the first cylinder (31) and the second cylinder (41). The middle plate (55) closes an end of the first cylinder (31) in the axial direction and an end of the second cylinder (41) in the axial direction. 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).

[0081] A central hole is formed in a center portion of the middle plate (55) so as to penetrate the middle plate (55) in the axial direction. The intermediate shaft portion (90b) of the shaft (90) is inserted into the central hole.

[0082] As shown in FIG. 3, the middle plate (55) has an intermediate passage (16c) which is part of the suction passage (16). The intermediate passage (16c) penetrates the middle plate (55) in the axial direction. The intermediate passage (16c) allows the first passage (16a) and the second passage (16b) to communicate with each other.

[0083] The fourth flow path (61d) extending in the axial direction of the second flow path (61b) of the injection flow path (61) penetrates the middle plate (55).(2-4-5) Rear Head

[0084] The rear head (56) is disposed on the side of the second cylinder (41) opposite to the middle plate (55). The rear head (56) closes an end of the second cylinder (41) in the axial direction. Specifically, the rear head (56) closes the lower end surface (surface opposite to the electric motor (20)) of the second cylinder (41). The rear head (56) is an example of the closing member of the present disclosure.

[0085] The upper surface of the rear head (56) is in close contact with the lower end surface of the second cylinder (41). The rear head (56) rotatably supports the lower shaft portion (90c) of the shaft (90).

[0086] The rear head (56) has a first insertion hole (19) into which the suction pipe (14) is inserted, and a second insertion hole (60) into which the injection pipe (9c) is inserted. The first insertion hole (19) and the second insertion hole (60) each extend in the radial direction.

[0087] 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 from the tip end of the first insertion hole (19) in the axial direction. An upper end portion of the lower passage (16d) communicates with the second passage (16b).

[0088] The injection flow path (61) extends from the second insertion hole (60). The rear head (56) includes part of the first flow path (61a) of the injection flow path (61).

[0089] As shown in FIGS. 7 and 8, the rear head (56) has a second discharge port (57). The second discharge port (57) penetrates the rear head (56) in the thickness direction. The second discharge port (57) allows the internal space (R) and a second discharge space (not shown) to communicate with each other. As shown in FIG. 5, the outer peripheral edge of the second discharge port (57) is overlapped by the arc-shaped edge of the second discharge cutout (47). The second discharge port (57) is overlapped by the inner space of the second discharge cutout (47) in the axial direction of the shaft (90).

[0090] A portion of the rear head (56) around the second discharge port (57) is a second thin portion (58) having a smaller thickness than the other portion in the axial direction.

[0091] The second discharge port (57) is provided with a second discharge valve (59). The second discharge valve (59) covers the second discharge port (57). The second discharge valve (59) is apart from the second discharge port (57) when the pressure of the refrigerant in the second discharge space (not shown) reaches a predetermined value or more. When the second discharge valve (59) is apart from the second discharge port (57), the refrigerant is discharged from the second discharge space (not shown) through the second discharge port (57) to the internal space (R). The second discharge valve (59) covers the second discharge port (57) again after the refrigerant has been discharged to the internal space (R).(3) Operation

[0092] Now, an operation of the compressor (1) will be described with reference to FIG. 9. An operation of compressing the refrigerant by the first cylinder (31) and the first piston (34) and an operation of compressing the refrigerant by the second cylinder (41) and the second piston (44) are basically the same, except that the phases thereof are different by 180°. In the following description, the operation of compressing the refrigerant by the first cylinder (31) and the first piston (34) will be described in detail, and the description of the operation of compressing the refrigerant by the second cylinder (41) and the second piston (44) will be omitted.

[0093] In the compressor (1), once the electric motor (20) starts to rotate the rotor (22), the shaft (90) rotates and the first eccentric portion (91) rotates eccentrically. As the first eccentric portion (91) rotates eccentrically, the first piston (34) turns along the inner peripheral surface of the first cylinder (31) while restricting the rotation.

[0094] A suction phase of sucking the refrigerant into the first cylinder chamber (S1) will be described. Once the shaft (90) slightly rotates from a state (state (A) in FIG. 9) in which the rotational angle thereof is 0°, the position of contact between the first piston (34) and the first cylinder (31) passes by the inner circumferential end of the first suction port (17). At this time, suction of the refrigerant into the first suction space (71) starts.

[0095] The refrigerant is sucked from the suction pipe (14) via the suction passage (16) and the first suction port (17). As the rotational angle of the shaft (90) increases, the volume of the first suction space (71) gradually increases, and then the amount of refrigerant sucked into the first suction space (71) increases (states (B) to (H) in FIG. 9). This refrigerant suction phase continues until the rotational angle of the shaft (90) reaches 360°, and then shifts to a discharge phase.

[0096] The discharge phase of compressing the refrigerant in the first cylinder chamber (S1) and discharging the compressed refrigerant therefrom will be described. When the shaft (90) slightly rotates from a state (state (A) in FIG. 9) in which the rotational angle thereof is 0°, the position of contact between the first piston (34) and the first cylinder (31) passes by the inner peripheral end of the first suction port (17) again. At this time, confinement of the refrigerant in the first suction space (71) is completed.

[0097] The first suction space (71) connected to the first suction port (17) serves as the first discharge space (72) connected only to the first discharge port (51). From this state, compression of the refrigerant in the first discharge space (72) starts. As the rotational angle of the shaft (90) increases, the volume of the first discharge space (72) decreases, and the pressure of the first discharge space (72) increases. When the pressure of the first discharge space (72) exceeds a predetermined pressure, the first discharge valve (53) opens.

[0098] Once 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) of the casing (10), and is then discharged through the discharge pipe (15) to the outside of the compressor (1). This refrigerant discharge phase continues until the rotational angle of the shaft (90) reaches 360°, and then shifts to the suction phase.

[0099] In this manner, the suction phase and the discharge phase are alternately performed in the first cylinder chamber (S1). In the second cylinder chamber (S2), the suction phase and the discharge phase are alternately performed at a phase different from that in the first cylinder chamber (S1) by 180°. Accordingly, the compressor (1) continuously performs the refrigerant compression operation.

[0100] Here, the intermediate-pressure refrigerant, that is, carbon dioxide (CO2) is injected from the injection flow path (61) into the first cylinder chamber (S1) and the second cylinder chamber (S2) during compression. Specifically, when the pressure in the injection flow path (61) is higher than that in the first cylinder chamber (S1), the intermediate-pressure refrigerant is injected from the injection flow path (61) into the first cylinder chamber (S1). On the other hand, when the pressure in the first cylinder chamber (S1) increases and becomes higher than that in the injection flow path (61), the end of the first reed valve (62) opposite to the fastening hole (62a) in the injection flow path (61) is pressed against the peripheral edge of the first injection opening (31b) to close the injection flow path (61), thereby stopping the supply of the intermediate-pressure refrigerant.

[0101] Similarly, when the pressure in the injection flow path (61) is higher than that in the second cylinder chamber (S2), the intermediate-pressure refrigerant is injected from the injection flow path (61) into the second cylinder chamber (S2). On the other hand, when the pressure in the second cylinder chamber (S2) increases and becomes higher than that in the injection flow path (61), the end of the second reed valve (66) opposite to the fastening hole (66a) in the injection flow path (61) is pressed against the peripheral edge of the second injection opening (41b) to close the injection flow path (61), thereby stopping the supply of the intermediate-pressure refrigerant. In this manner, the rotary compressor (1) increases the compression efficiency by injecting the intermediate-pressure refrigerant.(6) Advantages of Embodiment

[0102] In the rotary compressor (1) according to this embodiment, the first flow path (61a) directly connected to the injection pipe (9c) is branched into the second flow path (61b) and the third flow path (61c). There is thus no need to directly connect the injection pipe (9c) to each of the cylinders (31, 41). Accordingly, the height of the rotary compressor (1) can be lowered as compared with the case where the injection pipe (9c) is directly connected to each of the two cylinders (31, 41). In the present embodiment, since CO2 having a relatively large pressure difference is used as a refrigerant, refrigerant leakage is likely to occur; however, by reducing the height of the compressor (1) in this manner, refrigerant leakage can be suppressed.

[0103] The second flow path (61b) is provided with the first reed valve (62). This first reed valve (62) can introduce the refrigerant into the first cylinder chamber (S1). In addition, the third flow path (61c) is provided with the second reed valve (66). This second reed valve (66) can introduce the refrigerant into the second cylinder chamber (S2).

[0104] The fourth flow path (61d) has an average flow path diameter larger than or equal to that of the first flow path (61a). This can reduce the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1) and the second cylinder chamber (S2) as compared to a case where the fourth flow path (61d) has a smaller average flow path diameter than the first flow path (61a).

[0105] The sum of the flow path areas of the second flow path (61b) and the third flow path (61c) is larger than or equal to the flow path area of the first flow path (61a). This can reduce the pressure loss of the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1) and the second cylinder chamber (S2) as compared to a case where the fourth flow path (61d) has a smaller flow path area than the first flow path (61a).

[0106] Part of the first flow path (61a) connected to the injection pipe (9c) is formed in the rear head (56), and the lower end of the injection muffler (80) is disposed below the lower end of the front head (50). This configuration can lower the center of gravity of the compressor (1).

[0107] The first bolt insertion hole (31c) is formed in the first cylinder (31). The first bolt insertion hole (31c) houses the portion of the bolt (65) other than the distal end such as the head of the bolt (65). This configuration easily reduces the thickness of the first reed valve (62) and the volume (dead volume) of the space connected to the first cylinder chamber (S1), as compared to the case where the first reed valve (62) has the first bolt insertion hole (31c). The second bolt insertion hole (41c) is formed in the second cylinder (41). The second bolt insertion hole (41c) houses the portion of the bolt (67) other than the distal end such as the head of the bolt (67). This configuration easily reduces the thickness of the second reed valve (66) and the volume (dead volume) of the space connected to the second cylinder chamber (S2), as compared to the case where the second reed valve (66) has the second bolt insertion hole (41c).

[0108] The second flow path (61b) and the first suction port (17) are disposed on both sides of a straight line connecting the vane housing hole (33) and the center of the first cylinder (31). The end of the second flow path (61b) on the side of the first cylinder chamber (S1) is inclined toward the vane housing hole (33) in the radially inward direction of the first cylinder (31). Accordingly, the end of the second flow path (61b) on the side of the first cylinder chamber (S1) and the first suction port (17) are spaced apart from each other in the circumferential direction of the first suction space (71), which can easily reduce the backflow of the refrigerant to the second flow path (61b).

[0109] Similarly, the third flow path (61c) and the second suction port (18) are disposed on both sides of a straight line connecting the vane housing hole (43) and the center of the second cylinder (41). The end of the third flow path (61c) on the side of the second cylinder chamber (S2) is inclined toward the vane housing hole (43) in the radially inward direction of the second cylinder (41). Accordingly, the end of the third flow path (61c) on the side of the second cylinder chamber (S2) and the second suction port (18) are spaced apart from each other in the circumferential direction of the second suction space (75), which can easily reduce the backflow of the refrigerant to the third flow path (61c).

[0110] The first recess (31a) having the first injection opening (31b) is inclined toward the vane housing hole (33) in the radially inward direction of the first cylinder (31). Accordingly, the first injection opening (31b) and the first suction port (17) are spaced apart from each other in the circumferential direction of the first suction space (71), which can easily reduce the backflow of the refrigerant to the second flow path (61b).

[0111] Similarly, the second recess (41a) having the second injection opening (41b) is inclined toward the vane housing hole (43) in the radially inward direction of the second cylinder (41). Accordingly, the second injection opening (41b) and the second suction port (18) are spaced apart from each other in the circumferential direction of the second suction space (75), which can easily reduce the backflow of the refrigerant to the third flow path (61c).

[0112] The first discharge cutout (37) and the second discharge cutout (47) are formed, thereby reducing a rapid change in the cross-sectional area of the discharge flow path. Accordingly, the flow path resistance of the discharge flow path can be reduced.<Other Embodiments>

[0113] The piston (34, 44) and the vane (36, 46) are not necessarily formed integrally with each other. The piston (34, 44) and the vane (36, 46) may be connected by a hinge.

[0114] In the embodiment described above, both the end of the second flow path (61b) on the side of the first cylinder chamber (S1) and the end of the third flow path (61c) on the side of the second cylinder chamber (S2) are inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31) and the second cylinder (41). However, only one of the end of the second flow path (61b) on the side of the first cylinder chamber (S1) or the end of the third flow path (61c) on the side of the second cylinder chamber (S2) may be inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31) and the second cylinder (41).

[0115] In the embodiment described above, both the first recess (31a) of the first cylinder (31) and the second recess (41a) of the second cylinder (41) are inclined toward the vane housing holes (33, 43) in the radially inward direction of the first cylinder (31) and the second cylinder (41), respectively. However, only one of the first recess (31a) or the second recess (41a) may be inclined toward the corresponding vane housing hole (33, 43) in the radially inward direction of the corresponding one of the first cylinder (31) or the second cylinder (41).

[0116] In the embodiment described above, the rear head (56) has the second insertion hole (60) into which the injection pipe (9c) is inserted, and part of the first flow path (61a) of the injection flow path (61). However, the rear head (56) does not necessarily have the injection flow path (61). One of the first cylinder (31) or the second cylinder (41) may have an insertion hole into which the injection pipe (9c) is inserted, and the entire first flow path (61a) and the entire second flow path (61b). Alternatively, the middle plate (55) may have an insertion hole (60) into which the injection pipe (9c) is inserted, the entire first flow path (61a), and the branching portion into the second flow path (61b) and the third flow path (61c).

[0117] It will be understood that the embodiments and variations described above can be modified with various changes in form and details without departing from the spirit and scope of the claims. The embodiments, the variations thereof, and the other embodiments may be combined and replaced with each other without deteriorating intended functions of the present disclosure.

[0118] The expressions such as "first," "second," "third," and so on described above are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.INDUSTRIAL APPLICABILITY

[0119] As described above, the present disclosure is useful for a rotary compressor and a refrigeration apparatus including the rotary compressor.DESCRIPTION OF REFERENCE CHARACTERS

[0120] 1Rotary Compressor S1First Cylinder Chamber S2Second Cylinder Chamber 9cInjection Pipe 10Casing 31First Cylinder 31aFirst Recess 31bFirst Injection Opening 31cFirst Bolt Insertion Hole 31eFirst Lateral Flow Path 31fFirst Communication Path 33Vane Housing Hole 34First Piston 36First Vane 41Second Cylinder 41aSecond Recess 41bSecond Injection Opening 41cSecond Bolt Insertion Hole 41eSecond Lateral Flow Path 41fSecond Communication Path 43Vane Housing Hole 44Second Piston 46Second Vane 50Front Head (Second Bearing) 51First Discharge Port 55Middle Plate 56Rear Head (First Bearing, Lower Bearing) 57Second Discharge Port 61Injection Flow Path 61aFirst Flow Path 61bSecond Flow Path 61cThird Flow Path 61dFourth Flow Path 62First Reed Valve 62aFastening Hole 65Bolt 66Second Reed Valve 66aFastening Hole 67Bolt 80Injection Muffler 90Shaft 100Refrigeration Apparatus

Examples

Embodiment Construction

[0028]Embodiments of the present disclosure will be described in detail below with reference to the drawings. The present disclosure is not limited to the embodiments shown below, and various changes can be made within the scope without departing from the technical concept of the present disclosure. Since each of the drawings is intended to illustrate the present disclosure conceptually, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for the sake of ease of understanding. In the following description, unless otherwise specified, an "axial direction" indicates a direction in which a shaft extends, a "radial direction" indicates a direction radially extending from the shaft, and a "circumferential direction " indicates a circumferential direction about the shaft. The terms "upper / above / top" and "lower / below / bottom" refer to directions when a rotary compressor (1) is viewed from the front. Some drawings may be illustrated without hatching to facilitate und...

Claims

1. A rotary compressor to which an injection pipe (9c) is connected, the rotary compressor comprising: a casing (10); a first cylinder (31, 41) disposed inside the casing (10) and having a first cylinder chamber (S1, S2); a first piston (34, 44) configured to eccentrically rotate in the first cylinder chamber (S1, S2); a second cylinder (31, 41) disposed inside the casing (10) and having a second cylinder chamber (S1, S2); a second piston (34, 44) configured to eccentrically rotate in the second cylinder chamber (S1, S2); a shaft (90) coupled to the first piston (34, 44) and the second piston (34, 44); a middle plate (55) disposed between the first cylinder (31, 41) and the second cylinder (31, 41); a first bearing (50, 56) disposed on a side of the first cylinder (31, 41) opposite to the middle plate (55) and pivotally supporting the shaft (90); and a second bearing (50, 56) disposed on a side of the second cylinder (31, 41) opposite to the middle plate (55) and pivotally supporting the shaft (90), wherein an injection flow path (61) communicating with the injection pipe (9c) is formed in the first cylinder (31, 41), the middle plate (55), and the second cylinder (31, 41), the injection flow path (61) includes: a first flow path (61a) connected to the injection pipe (9c); a second flow path (61b, 61c) branching from the first flow path (61a) and communicating with the first cylinder chamber (S1, S2); and a third flow path (61b, 61c) branching from the first flow path (61a) and communicating with the second cylinder chamber (S1, S2).

2. The rotary compressor of claim 1, wherein the second flow path (61b, 61c) is provided with a first reed valve (62, 66) to move up and down at an end thereof in an axial direction of the shaft (90), and the third flow path (61b, 61c) is provided with a second reed valve (62, 66) to move up and down at an end thereof in the axial direction.

3. The rotary compressor of claim 1 or 2, wherein the second flow path (61b, 61c) or the third flow path (61b, 61c) has a fourth flow path (61d) extending in the axial direction of the shaft (90) and penetrating the middle plate (55), and the fourth flow path (61d) has an average flow path diameter larger than or equal to that of the first flow path (61a).

4. The rotary compressor of any one of claims 1 to 3, wherein a sum of flow path areas of the second flow path (61b, 61c) and the third flow path (61b, 61c) is larger than or equal to a flow path area of the first flow path (61a).

5. The rotary compressor of any one of claims 1 to 4, further comprising: an injection muffler (80) connected to the injection pipe (9c), wherein the axial direction of the shaft (90) is a vertical direction, the first bearing (56) is a lower bearing, the second bearing (50) is an upper bearing, part of the first flow path (61a) is formed in the first bearing (56), and a lower end of the injection muffler (80) is located below a lower end of the second bearing (50).

6. The rotary compressor of claim 2, wherein the first cylinder (31, 41) has an injection opening (31a, 41a) open at one end in the axial direction and a bolt insertion hole (31c, 41c) penetrating the first cylinder (31, 41) in the axial direction, the first reed valve (62, 66) is attached to the first cylinder (31, 41) by a bolt (65, 67) so as to open and close the injection opening (31a, 41a), the first reed valve (62, 66) has a fastening hole (62a, 66a) in a surface facing the first cylinder (31, 41), and the bolt (65, 67) is inserted into the bolt insertion hole (31c, 41c) and has a distal end fastened to the fastening hole (62a, 66a).

7. The rotary compressor of any one of claims 1 to 6, wherein the first cylinder (31, 41) has a vane housing hole (33, 43) configured to house a vane (36, 46) of the first piston (34, 44), and an end of the second flow path (61b, 61c) on a side of the first cylinder chamber (S1, S2) is inclined toward the vane housing hole (33, 43) in a radially inward direction of the first cylinder (31, 41).

8. The rotary compressor of claim 7, wherein the first cylinder (31, 41) has the vane housing hole (33, 43) configured to house the vane (36, 46) of the first piston (34, 44), the first cylinder (31, 41) has, in one axial end surface thereof, a recess (31a, 41a) extending while being inclined toward the vane housing hole (33, 43) in the radially inward direction of the first cylinder (31, 41), the recess (31a, 41a) has, in a bottom surface thereof, an injection opening (31b, 41b). the second flow path (61b, 61c) includes a lateral flow path (31e, 41e) extending in the radial direction, and a communication path (31f, 41f) coupling the lateral flow path (31e, 41e) and the injection opening (31b, 41b) in the axial direction, the recess (31a, 41a) houses a first reed valve (62, 66), and an extending direction of the lateral flow path (31e, 41e) and an extending direction of the recess (31a, 41a) are offset from each other by 5 degrees or more.

9. The rotary compressor of any one of claims 1 to 8, wherein the first bearing (50, 56) has a discharge port (51, 57) for discharging a refrigerant from the first cylinder chamber (S1, S2), the first cylinder (31, 41) has, in an inner peripheral surface thereof, a discharge cutout (37, 47) recessed toward an outer circumference so that an inner space of the discharge cutout (37, 47) overlaps the discharge port (51, 57) in the axial direction of the shaft (90), and the second flow path (61b, 61c) communicates with the inner space of the discharge cutout (37, 47).

10. The rotary compressor of any one of claims 1 to 9, wherein the refrigerant supplied from the injection pipe (9c) to the first cylinder chamber (S1) and the second cylinder chamber (S2) is CO2.

11. A refrigeration apparatus comprising: the rotary compressor of any one of claims 1 to 10.

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