Rotary compressor and refrigeration device

Abstract

In a rotary compressor, a cylinder (31, 41, 231, 241, 331) and a closing member (50, 55, 56, 250, 255, 256, 350, 356) are fixed to each other by a plurality of bolts (B) extending in an axial direction of a rotary shaft (90). The plurality of bolts (B) include: a first bolt (B1) between a suction pipe (14, 214a, 214b, 314) and a housing (33, 43) housing a blade (38, 48) as viewed in the axial direction; and a second bolt (B2) between the housing (33, 43) and an imaginary line (IL), which is symmetrical to a center line (AL) of the suction pipe (14, 214a, 214b, 314) with respect to the housing (33, 43), as viewed in the axial direction.

Description

TECHNICAL FIELD

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

[0002] A structure of a rotary compressor is known in which a cylinder having a cylinder chamber therein and a closing member for closing the cylinder chamber are fixed by bolts.

[0003] A hermetic compressor described in Patent Document 1 includes a cylinder, a front head (as a closing member) on one surface of the cylinder, and a rear head (as a closing member) on the other surface of the cylinder, thereby defining a cylinder chamber in which a piston eccentrically rotates. In the hermetic compressor described in Patent Document 1, the front head and the rear head are fixed to the cylinder by bolts so that distortion caused by thermal expansion based on the difference in the temperature distribution of the cylinder is substantially the same over the entire circumference of the cylinder surrounding the cylinder chamber.

[0004] In the hermetic compressor described in Patent Document 1, the bolts are provided only on the discharge side near the housing hole housing the blade.CITATION LISTPATENT DOCUMENT

[0005] Patent Document 1: Japanese Unexamined Patent Publication No. 2009-144619SUMMARY OF THE INVENTIONTECHNICAL PROBLEMS

[0006] If bolts are provided only on one side near the housing hole as in the rotary compressor described in Patent Document 1, the axial forces of the bolts become unbalanced. Accordingly, in a portion where a strong axial force is applied, a gap between the closing member and the blade or between the closing member and the piston becomes narrower, while in a portion where the axial force is hardly applied, the gap between the closing member and the blade or between the closing member and the piston becomes wider. Thus, the gap may fail to have an appropriate size. The gap between the closing member and the blade or between the closing member and the piston affects the compression efficiency. In view of improving the compression efficiency, there is room for improvement in the typical rotary compressor.

[0007] It is an object of the present disclosure to improve the compression efficiency of a rotary compressor.SOLUTION TO THE PROBLEMS

[0008] A first aspect of the present disclosure is directed to a rotary compressor. The rotary compressor includes: a cylinder (31, 41, 231, 241, 331) having a cylinder chamber (S1, S2) therein; a piston (35, 45) configured to turn along an inner surface of the cylinder chamber (S1, S2); a rotary shaft (90) configured to turn the piston (35, 45); a blade (38, 48) configured to divide the cylinder chamber (S1, S2) into a suction space (71, 75) and a discharge space (72, 76); a closing member (50, 55, 56, 250, 255, 256, 350, 356) configured to close an end of the cylinder chamber (S1, S2) in an axial direction of the rotary shaft (90); and a suction pipe (14, 214a, 214b, 314) configured to supply a refrigerant to the suction space (71, 75). The cylinder (31, 41, 231, 241, 331) and the closing member (50, 55, 56, 250, 255, 256, 350, 356) are fixed to each other by a plurality of bolts (B) extending in the axial direction of the rotary shaft (90). The plurality of bolts (B) includes: a first bolt (B1) between the suction pipe (14, 214a, 214b, 314) and a housing (33, 43) housing the blade (38, 48), as viewed in the axial direction; and a second bolt (B2) between the housing (33, 43) and an imaginary line (IL) that is symmetrical to a center line (AL) of the suction pipe (14, 214a, 214b, 314) with respect to the housing (33, 43), as viewed in the axial direction.

[0009] In the first aspect, the first bolt (B1) and the second bolt (B2) are arranged on the opposite sides of the housing (33, 43), near the housing (33, 43). This configuration can facilitate balancing of the axial forces of the bolts (B) near the housing (33, 43), thereby improving the compression efficiency.

[0010] A second aspect of the present disclosure is an embodiment of the first aspect. In the second aspect, the plurality of bolts (B) further include: a third bolt (B3) disposed closer to the suction pipe (14, 214a, 214b, 314) than the housing (33, 43) is so that the suction pipe (14, 214a, 214b, 314) is interposed between the first bolt (B1) and the third bolt (B3), as viewed in the axial direction.

[0011] In the second aspect, the distance between the first bolt (B1) and the second bolt (B2) and the distance between the first bolt (B1) and the third bolt (B3) can be substantially equal to each other. Accordingly, the rotary compressor can facilitate balancing of the axial forces of the bolts (B) near the blade (38, 48), thereby improving the compression efficiency.

[0012] A third aspect of the present disclosure is an embodiment of the first or second aspect. In the third aspect, as viewed in the axial direction, a first distance (D1) from a center (X) of the rotary shaft (90) to a farthermost point of the housing (33, 43) from the center (X) of the rotary shaft (90) is longer than a second distance (D2) from the center (X) of the rotary shaft (90) to a center (BC1) of the first bolt (B1), and as viewed in the axial direction, the first distance (D1) is longer than a third distance (D3) from the center (X) of the rotary shaft (90) to a center (BC2) of the second bolt (B2).

[0013] In the third aspect, the first bolt (B1) and the second bolt (B2) can be arranged close to the cylinder chamber (S1, S2). Accordingly, the rotary compressor can set the gap between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the blade (38, 48) or between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the piston (35, 45) in the cylinder chamber (S1, S2) to an appropriate size, and improve the compression efficiency.

[0014] A fourth aspect of the present disclosure is an embodiment of any one of the first to third aspects. In the fourth aspect, as viewed in the axial direction, the first bolt (B1) and the second bolt (B2) are arranged line-symmetrically with respect to a straight line extending in a direction in which the blade (38, 48) extends when the piston (35, 45) is located at top dead center.

[0015] In the fourth aspect, since the distance from the first bolt (B1) to the blade (38, 48) and the distance from the second bolt (B2) to the blade (38, 48) are equal to each other, the axial forces of the bolts (B) near the blade (38, 48) are easily balanced. Accordingly, the rotary compressor can set the gap between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the blade (38, 48) or between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the piston (35, 45) in the cylinder chamber (S1, S2) to an appropriate size, and improve the compression efficiency.

[0016] A fifth aspect of the present disclosure is an embodiment of any one of the first to third aspects. In the fifth aspect, as viewed in the axial direction, a second distance (D2) from the center (X) of the rotary shaft (90) to a center (BC1) of the first bolt (B1) is longer than a third distance (D3) from the center (X) of the rotary shaft (90) to a center (BC2) of the second bolt (B2).

[0017] In the fifth aspect, the first bolt (B1) can be spaced apart from the cylinder chamber (S1, S2). This can reduce the amount of deformation of a suction-side portion of the cylinder (31, 41, 231, 241, 331) by the axial forces of the bolts. Accordingly, the rotary compressor can set the gap between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the piston (35, 45) to an appropriate size, and reduce the seizing.

[0018] A sixth aspect of the present disclosure is an embodiment of any one of the first to third aspects. In the sixth aspect, as viewed in the axial direction, a third distance (D3) from the center (X) of the rotary shaft (90) to a center (BC2) of the second bolt (B2) is longer than a second distance (D2) from the center (X) of the rotary shaft (90) to a center (BC1) of the first bolt (B1).

[0019] In the sixth aspect, the second bolt (B2) can be spaced apart from the cylinder chamber (S1, S2). This can reduce the amount of deformation of a discharge-side portion of the cylinder (31, 41, 231, 241, 331) by the axial forces of the bolts. Accordingly, the rotary compressor can set the gap between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the piston (35, 45) to an appropriate size, and reduce the seizing.

[0020] A seventh aspect of the present disclosure is an embodiment of any one of the first to sixth aspects. In the seventh aspect, the suction pipe (14, 214a, 214b, 314) is disposed in the closing member (50, 55, 56, 250, 255, 256, 350, 356), the cylinder (31, 41, 231, 241, 331) has a suction port (17, 18) through which the refrigerant supplied from the suction pipe (14, 214a, 214b, 314) is supplied to the suction space (71, 75), and as viewed in the axial direction, the suction port (17, 18) extends to a position closer to the housing (33, 43) than the suction pipe (14, 214a, 214b, 314) is and is inclined with respect to a direction of insertion of the suction pipe (14, 214a, 214b, 314).

[0021] In the seventh aspect, the rotary compressor supplies the refrigerant at a point closer to top dead center, thereby improving the compression efficiency.

[0022] An eighth aspect of the present disclosure is an embodiment of any one of the first to seventh aspects. In the eighth aspect, the refrigerant is carbon dioxide.

[0023] In the eighth aspect, since carbon dioxide with a relatively low density is used as the refrigerant, the discharge space (72, 76) tends to have a high pressure. The rotary compressor can set the gap between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the blade (38, 48) or between the closing member (50, 55, 56, 250, 255, 256, 350, 356) and the piston (35, 45) to an appropriate size, thereby improving the compression efficiency even in use of carbon dioxide as the refrigerant.

[0024] A ninth aspect of the present disclosure is directed to a refrigeration apparatus. The refrigeration apparatus includes the rotary compressor (1) of any one of the first to eighth aspects.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [FIG. 1] FIG. 1 is a piping system diagram of a refrigeration apparatus including a rotary compressor according to a first embodiment. [FIG. 2] FIG. 2 is a vertical cross-sectional view of the rotary compressor. [FIG. 3] FIG. 3 is a horizontal cross-sectional view of a first cylinder. [FIG. 4] FIG. 4 is a horizontal cross-sectional view of a second cylinder. [FIG. 5] FIG. 5 is a cross-sectional view taken along line IV-IV in FIG. 3. [FIG. 6] FIG. 6 is a view of a rear head as viewed from an internal space in an axial direction. [FIG. 7] FIG. 7 shows an operation of a compression mechanism. [FIG. 8] FIG. 8 illustrates a positional relationship of bolts. [FIG. 9] FIG. 9 illustrates a distance relationship of the bolts. [FIG. 10] FIG. 10 illustrates a positional relationship of bolts of a rotary compressor according to a first variation. [FIG. 11] FIG. 11 illustrates a positional relationship of bolts of a rotary compressor according to a second variation. [FIG. 12] FIG. 12 is a vertical sectional view of a rotary compressor with two suction pipes. [FIG. 13] FIG. 13 is a vertical sectional view of a rotary compressor with a single-cylinder compression mechanism. DESCRIPTION OF EMBODIMENTS

[0026] 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 the direction in which a rotation axis extends, a "radial direction" indicates the direction radially extending from the rotation axis, and a "circumferential direction" indicates the circumferential direction about the rotation axis. The terms "upper" and "lower" 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

[0027] 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 for conditioning 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 expansion valve (5), and an economizer heat exchanger (4b). The indoor unit (8) includes an indoor heat exchanger (6). The outdoor unit (7) and the indoor unit (8) are connected together via a connection pipe (9a) to constitute a refrigerant circuit (9).

[0028] The compressor (1) according to this embodiment is of a type in which a blade (38, 48) eccentrically rotates, while being connected to a specific point of the outer circumference of a piston (35, 45), and is a so-called swing type in which the blade (38, 48) and the piston (35, 45) are integrally formed. The compressor (1) compresses a low-pressure gas refrigerant into a high-pressure gas refrigerant. The compressor (1) is driven by a compressor motor. A part of an 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 (i.e., the low pressure) of the gas refrigerant sucked into the compressor (1) and the pressure (i.e., the high pressure) of the gas refrigerant discharged from the compressor (1). The refrigerant is not particularly limited, but is, for example, carbon dioxide (CO 2 ).

[0029] The four-way switching valve (3) switches the connection state of the 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 the broken lines in FIG. 1. When the refrigeration apparatus (100) performs a heating operation, the four-way switching valve (3) implements the connection state indicated by the solid lines in FIG. 1.

[0030] The outdoor heat exchanger (4a) exchanges heat between outdoor air and the refrigerant circulating in the refrigerant circuit (9). The outdoor heat exchanger (4a) includes 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 an absorber (evaporator) for the refrigerant in the heating operation.

[0031] 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).

[0032] 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 a gas refrigerant and a liquid refrigerant, and stores the liquid refrigerant. The gas refrigerant separated in the accumulator (2) is sent to the suction port of the compressor (1).

[0033] 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 a economizer pipe (9b). The economizer pipe (9b) branches off from the refrigerant circuit (9) between the economizer heat exchanger (4b) and the expansion valve (5) and is connected to an injection pipe (9c). 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 that has exchanged heat in the economizer heat exchanger (4b) are, as intermediate-pressure refrigerants, supplied to the injection pipe (9c).

[0034] 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.

[0035] The refrigeration apparatus (100) performs a heating operation and a 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

[0036] As illustrated in FIG. 2, the compressor (1) includes a closed container (10), an electric motor (20), and a compression mechanism (30). The electric motor (20) and the compression mechanism (30) are housed in the closed container (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 closed container (10) so that the internal space (R) has a high pressure.(2-1) Rotary Compressor

[0037] The closed container (10) is vertically long. Specifically, the closed container (10) includes a cylindrical barrel (11) extending in an 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 through 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

[0038] The electric motor (20) is housed in the closed container (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) Rotary Shaft

[0039] A rotary shaft (90) extends in the up-down direction in the closed container (10). The rotary shaft (90) is driven by the electric motor (20). An upper portion of the rotary shaft (90) is connected to the rotor (22) of the electric motor (20).

[0040] A lower portion of the rotary shaft (90) includes, in order from top to bottom, an upper shaft portion (90a), a first eccentric portion (91), an intermediate shaft portion (90b), a second eccentric portion (92), and a lower shaft portion (90c). The upper shaft portion (90a), the first eccentric portion (91), the intermediate shaft portion (90b), the second eccentric portion (92), and the lower shaft portion (90c) are integrally formed.

[0041] The first eccentric portion (91) and the second eccentric portion (92) are eccentric with respect to the axis of the rotary shaft (90). The first eccentric portion (91) and the second eccentric portion (92) have larger diameters than the upper shaft portion (90a), the intermediate shaft portion (90b), and the lower shaft portion (90c). The eccentric direction of the first eccentric portion (91) with respect to the rotation center axis of the rotary shaft (90) differs from the eccentric direction of the second eccentric portion (92) with respect to the rotation center axis of the rotary shaft (90) by 180°.

[0042] The intermediate shaft portion (90b) is disposed between the first eccentric portion (91) and the second eccentric portion (92). The intermediate shaft portion (90b) connects the first eccentric portion (91) and the second eccentric portion (92).(2-4) Compression Mechanism

[0043] As shown in FIG. 2, the compression mechanism (30) is housed in the closed container (10). The compression mechanism (30) compresses the sucked refrigerant, and discharges the compressed refrigerant to the internal space (R) of the closed container (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 rotary shaft (90), a front head (50), a first cylinder (31), the first piston (35), a first blade (38), a middle plate (55), a second cylinder (41), the second piston (45), a second blade (48), and a rear head (56). The front head (50), the first cylinder (31), the middle plate (55), the second cylinder (41), and the rear head (56) are fixed by a plurality of bolts, namely, a first bolt (B1) to a seventh bolt (B7), not to move relative to each other. In the following description, when it is unnecessary to distinguish among the first to seventh bolts (B1 to B7), the first bolt (B1) to the seventh bolt (B7) may be simply referred to as bolts (B).(2-4-1) Cylinder

[0044] As shown in FIGS. 2 to 4, the first cylinder (31) and the second cylinder (41) are thick disk-shaped members. The first cylinder (31) and the second cylinder (41) each include a cylinder bore (32, 42), a blade housing hole (33, 43), a suction port (17, 18), an injection passage (61, 62), an injection port (63, 64), and a plurality of insertion holes (81, 82).

[0045] The cylinder bore (32, 42) is a circular hole penetrating the cylinder (31, 41) in its thickness direction. 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 (35). The second cylinder bore (42) of the second cylinder (41) houses the second piston (45).

[0046] In the first cylinder (31), a first cylinder chamber (S1) is formed between the wall surface of the first cylinder bore (32) and the first piston (35). In the second cylinder (41), a second cylinder chamber (S2) is formed between the wall surface of the second cylinder bore (42) and the second piston (45).

[0047] The blade housing holes (33, 43) are holes extending from the inner peripheral surfaces of the cylinders (31, 41) (i.e., the outer edges of the cylinder bores (32, 42)) toward the outer sides of the cylinders (31, 41) in the radial direction, respectively. These blade housing holes (33, 43) pass through the cylinders (31, 41) in the thickness direction, respectively. The first blade housing hole (33) of the first cylinder (31) houses the first blade (38). The second blade housing hole (43) of the second cylinder (41) houses the second blade (48). The blade housing hole (33, 43) is an example of the container.

[0048] The first cylinder (31) has a first passage (16a) which is a 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 side of the first blade housing hole (33) in FIG. 3. The second cylinder (41) has a second passage (16b) which is a part of the suction passage (16). The second passage (16b) penetrates the second cylinder (41) in the thickness direction. The second passage (16b) is disposed on the right side of the second blade housing hole (43) in FIG. 4.

[0049] The suction port (17, 18) extends 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). The second suction port (18) of the second cylinder (41) extends from the second passage (16b) toward the second cylinder chamber (S2). The suction port (17, 18) extends toward the cylinder chamber (S1, S2) to be closer to the blade housing hole (33, 43) than the suction passage (16) is, as viewed in the axial direction. The suction port (17, 18) extends to be inclined with respect to the direction of insertion of the suction pipe (14).

[0050] The injection passage (61, 62) is for supplying the refrigerant to the cylinder chamber (S1, S2) separately from the suction passage (16). The first injection passage (61) of the first cylinder (31) is disposed on the left side of the first blade housing hole (33) in FIG. 3. That is, the first injection passage (61) of the first cylinder (31) is disposed on the side of the first blade housing hole (33) opposite to the first passage (16a). The second injection passage (62) of the second cylinder (41) is disposed on the left side of the second blade housing hole (43) in FIG. 4. That is, the second injection passage (62) of the second cylinder (41) is disposed on the side of the second blade housing hole (43) opposite to the second passage (16b).

[0051] The injection port (63, 64) extends from the injection passage (61, 62) toward the cylinder chamber (S1, S2). The injection port (63, 64) extends toward the cylinder chamber (S1, S2) to be closer to the blade housing hole (33, 43) than the injection passage (61, 62) is, as viewed in the axial direction.

[0052] The insertion holes (81, 82) are holes through which the bolts (B) are inserted. Seven insertion holes (81, 82) are provided. The circumferential arrangement of the second insertion holes (82) in the second cylinder (41) corresponds to the circumferential arrangement of the first insertion holes (81) in the first cylinder (31). The first insertion holes (81) and the second insertion holes (82) overlap each other as viewed in the axial direction. The insertion holes (81, 82) may be threaded or unthreaded. The detailed arrangement of the insertion holes (81, 82) will be described later together with the arrangement of the bolts (B).

[0053] As viewed in the axial direction, the outer shapes of the cylinders (31, 41) are symmetrical with respect to a specific straight line (SL). The specific straight line (SL) will be described later.(2-4-2) Piston

[0054] The first piston (35) is housed in the first cylinder (31). The first piston (35) turns inside the first cylinder chamber (S1). The first piston (35) slides on both the front head (50) and the middle plate (55).

[0055] The first piston (35) is in a ring shape. The first piston (35) is formed in a slightly thick cylindrical shape. The first eccentric portion (91) of the rotary shaft (90) is inserted into the first piston (35). The first piston (35) turns along the inner circumferential surface of the first cylinder chamber (S1) of the first cylinder (31) due to the rotation of the first eccentric portion (91).

[0056] The second piston (45) is a member having the same shape and size and made of the same material as the first piston (35). The first piston (35) and the second piston (45) are arranged in an up-down direction, inverted relative to each other.

[0057] The second piston (45) is housed in the second cylinder (41). The second piston (45) turns inside the second cylinder chamber (S2). The second piston (45) slides on both the rear head (56) and the middle plate (55).

[0058] The second piston (45) is in a ring shape. The second piston (45) is formed in a slightly thick cylindrical shape. The second eccentric portion (92) of the rotary shaft (90) is inserted into the second piston (45). The second piston (45) turns along the inner circumferential surface of the second cylinder chamber (S2) of the second cylinder (41) due to the rotation of the second eccentric portion (92).(2-4-3) Blade

[0059] As shown in FIGS. 3 and 4, the first blade (38) and the second blade (48) are slightly thick, flat rectangular plate-shaped members. The first blade (38) is formed integrally with the first piston (35). The second blade (48) is formed integrally with the second piston (45). The blades (38, 48) extend outward in the radial direction from the outer circumferential surfaces of the pistons (35, 45).

[0060] The first blade (38) is fitted in the first blade housing hole (33). The first blade (38) is sandwiched between a pair of first bushings (70) provided in the first cylinder (31) from both sides. The first blade (38) integral with the first piston (35) is supported by the first cylinder (31) via these first bushings (70) to freely oscillate and move back and forth.

[0061] The first blade (38) divides the first cylinder chamber (S1) into a first suction space (71) and a first discharge space (72). The first blade (38) restricts the rotation of the first piston (35) itself when the first piston (35) turns. Accordingly, the first piston (35) does not rotate but turns along the inner surface of the first cylinder chamber (S1).

[0062] The second blade (48) is fitted in the second blade housing hole (43). The second blade (48) is sandwiched between a pair of second bushings (74) provided in the second cylinder (41) from both sides. The second blade (48) integral with the second piston (45) is supported by the second cylinder (41) via these second bushings (74) to freely oscillate and move back and forth.

[0063] The second blade (48) divides the second cylinder chamber (S2) into a second suction space (75) and a second discharge space (76). The second blade (48) restricts the rotation of the second piston (45) itself when the second piston (45) turns. Accordingly, the second piston (45) does not rotate but turns along the inner surface of the second cylinder chamber (S2).(2-4-4) Front Head

[0064] As shown in FIG. 2, 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 (i.e., the surface closer to the electric motor (20)) of the first cylinder (31). The front head (50) is an example of the 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.

[0065] 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. 2). 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 rotary shaft (90).

[0066] As shown in FIG. 5, 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.

[0067] The first discharge port (51) is provided with a first discharge valve (53). 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) becomes higher than or equal to a predetermined value. When the first discharge valve (53) is apart from the first discharge port (51), the refrigerant is discharged from the first discharge space (72) 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 into the internal space (R).

[0068] The first body portion (50a) has a plurality of fastening holes (83). The fastening holes (83) are holes to which the bolts (B) are fastened. The fastening holes (83) are bottomed holes extending in the axial direction and do not penetrate the first body portion (50a). The circumferential arrangement of the fastening holes (83) corresponds to the circumferential arrangement of the insertion holes (81, 82) of the cylinder (31, 41).(2-4-5) Middle Plate

[0069] As shown in FIG. 2, the middle plate (55) is sandwiched between the first cylinder (31) and the second cylinder (41) in the axial direction. 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). The middle plate (55) is an example of the closing member of the present disclosure.

[0070] A central hole is formed in a central portion of the middle plate (55) to penetrate the middle plate (55) in the axial direction. The intermediate shaft portion (90b) of the rotary shaft (90) is inserted into the central hole.

[0071] The middle plate (55) has an intermediate passage (16c) which is a 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.

[0072] Although not shown in detail, the middle plate (55) has a passage that allows the first injection passage (61) and the second injection passage (62) to communicate with each other.

[0073] The middle plate (55) has a plurality of intermediate insertion holes (84). The intermediate insertion holes (84) are holes through which the bolts (B) are inserted. The intermediate insertion holes (84) penetrate the middle plate (55) in the thickness direction. The circumferential arrangement of the intermediate insertion holes (84) corresponds to the circumferential arrangement of the insertion holes (81, 82) of the cylinder (31, 41). The intermediate insertion holes (84) may be threaded or unthreaded.(2-4-6) Rear Head

[0074] As shown in FIG. 2, 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 (i.e., the 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. The rear head (56) includes a second body portion (56a), a lower bearing portion (56b), and an expansion portion (56c). The second body portion (56a) and the lower bearing portion (56b) serve as a single member.

[0075] As shown in FIG. 6, the second body portion (56a) is formed in a substantially circular thick plate shape. The lower surface of the second body portion (56a) is in close contact with the lower end surface of the second cylinder (41). The lower bearing portion (56b) is formed in a cylindrical shape extending from the second body portion (56a) toward the side opposite to the second cylinder (41) (downward in FIG. 2). The lower bearing portion (56b) is located in a center portion of the second body portion (56a). The lower bearing portion (56b) rotatably supports the lower shaft portion (90c) of the rotary shaft (90).

[0076] The expansion portion (56c) expands outward from the second body portion (56a) in the radial direction. The expansion portion (56c) has a first insertion hole (19) into which the suction pipe (14) is inserted, and a second insertion hole (60) into which an injection pipe (not shown) is inserted. The first insertion hole (19) and the second insertion hole (60) each extend in the radial direction.

[0077] A lower passage (16d), which is a part of the suction passage (16), extends from the first insertion hole (19). The lower passage (16d) extends upward from the tip of the first insertion hole (19) in the axial direction. The upper end of the lower passage (16d) communicates with the second passage (16b).

[0078] A lower injection passage (65) extends from the second insertion hole (60). The lower injection passage (65) extends upward from the tip of the second insertion hole (60) in the axial direction. The upper end of the lower injection passage (65) communicates with the second injection passage (62).

[0079] As shown in FIGS. 5 and 6, the second body portion (56a) has a second discharge port (57). The second discharge port (57) penetrates the second body portion (56a) in the thickness direction. The second discharge port (57) allows the internal space (R) and the second discharge space (76) to communicate with each other.

[0080] 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 (76) becomes higher than or equal to a predetermined value. When the second discharge valve (59) is apart from the second discharge port (57), the refrigerant is discharged from the second discharge space (76) 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 into the internal space (R).

[0081] The rear head (56) has a plurality of lower insertion holes (85). The lower insertion holes (85) are holes through which the bolts (B) are inserted. The lower insertion holes (85) penetrate the rear head (56) in the axial direction. The circumferential arrangement of the lower insertion holes (85) corresponds to the circumferential arrangement of the insertion holes (81, 82) of the cylinder (31, 41). The lower insertion holes (85) may be threaded or unthreaded.(3) Operation

[0082] Now, an operation of the compressor (1) will be described with reference to FIG. 7. The compression operation of the refrigerant by the first cylinder (31) and the first piston (35) and the refrigerant compression operation by the second cylinder (41) and the second piston (45) are basically the same, but only the phases are different by 180°. In the following description, the refrigerant compression operation by the first cylinder (31) and the first piston (35) will be described in detail, and the description of the refrigerant compression operation by the second cylinder (41) and the first piston (35) will be omitted.

[0083] In the compressor (1), when the electric motor (20) is started to rotate the rotor (22), the rotary shaft (90) rotates and the first eccentric portion (91) rotates eccentrically. As the first eccentric portion (91) rotates eccentrically, the first piston (35) turns along the inner circumferential surface of the first cylinder (31) while restricting its rotation.

[0084] A suction phase of sucking the refrigerant into the first cylinder chamber (S1) will be described. When the rotary shaft (90) slightly rotates from the state (state of (A) in FIG. 7) where the rotational angle is 0°, the position of contact between the first piston (35) and the first cylinder (31) passes by the inner peripheral end of the first suction port (17). At this time, suction of the refrigerant into the first suction space (71) starts.

[0085] The refrigerant is sucked from the suction pipe (14) through the suction passage (16) and the first suction port (17). As the rotational angle of the rotary 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 of (B) to (H) in FIG. 7). This suction phase of sucking the refrigerant continues until the rotational angle of the rotary shaft (90) reaches 360°, and then shifts to a discharge phase.

[0086] The discharge phase of compressing the refrigerant in the first cylinder chamber (S1) and discharging the compressed refrigerant therefrom will be described. When the rotary shaft (90) slightly rotates from the state (state of (A) in FIG. 7) where the rotational angle is 0°, the position of contact between the first piston (35) and the first cylinder (31) passes by the inner peripheral end of the first suction port (17). At this time, confinement of the refrigerant in the first suction space (71) is completed.

[0087] 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 rotary shaft (90) increases, the volume of the first discharge space (72) decreases, and then 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.

[0088] When the first discharge valve (53) opens, the refrigerant in the first discharge space (72) is discharged through the first discharge port (51), flows into the internal space (R) of the closed container (10), and is then discharged to the outside of the compressor (1) through the discharge pipe (15). This discharge phase of discharging the refrigerant continues until the rotational angle of the rotary shaft (90) reaches 360°, and then shifts to the suction phase.

[0089] In this manner, the suction phase and the discharge phase alternate in the first cylinder chamber (S1). In the second cylinder chamber (S2), the suction phase and the discharge phase alternate at a phase different from that in the first cylinder chamber (S1) by 180°. Accordingly, the compressor (1) continuously performs the refrigerant compression operation.(4) Arrangement of Bolts

[0090] The axial forces of the bolts (B) strongly act near the bolts (B). Near the bolts (B), the gaps between the front head (50) and the first piston (35) and between the front head (50) and the first blade (38), the gaps between the middle plate (55) and the first piston (35) and between the middle plate (55) and the first blade (38), the gaps between the middle plate (55) and the second piston (45) and between the middle plate (55) and the second blade (48), and the gaps between the rear head (56) and the second piston (45) and between the rear head (56) and the second blade (48) (hereinafter, these gaps are collectively referred to as axial gaps) tend to be narrow in the axial direction. On the other hand, at points away from the bolts (B), the axial forces of the bolts (B) are less likely to act and the axial gaps tend to be wider.

[0091] The axial gaps affect the compression efficiency. In particular, the axial gap between the blade (38, 48), which defines the suction space (71, 75) and the discharge space (72, 76), and the front head (50), between the blade (38, 48) and the middle plate (55), and between the blade (38, 48) and the rear head (56) tend to affect the compression efficiency.

[0092] In the compressor (1) according to this embodiment, the plurality of bolts (B) are arranged near the blade (38, 48) in view of the balance of the axial forces of the bolts (B). Hereinafter, the arrangement of the bolts (B) will be described in detail with reference to FIGS. 8 and 9. Since the bolts (B) are arranged in the same manner in both the first cylinder (31) and the second cylinder (41), the first cylinder (31) will be described as a reference in the following.

[0093] As shown in FIG. 8, the plurality of bolts (B) include seven bolts, namely, the first bolt (B1) to the seventh bolt (B7). The plurality of bolts (B) have the same configuration, diameter, and axial length.

[0094] Around the first blade housing hole (33), the first bolt (B1) is disposed closer to the suction port (17) in the circumferential direction, and the second bolt (B2) is disposed closer to the discharge port (51) in the circumferential direction. Specifically, the first bolt (B1) is disposed between the suction pipe (14) and the first blade housing hole (33) as viewed in the axial direction. As viewed in the axial direction, the second bolt (B2) is disposed between the first blade housing hole (33) and an imaginary line (IL), which is symmetrical to the center line (AL) of the suction pipe (14) with respect to the first blade housing hole (33). In this embodiment, as viewed in the axial direction, the center line (AL) and the imaginary line (IL) are line-symmetrical with respect to the specific straight line (SL) which connects the center (X) of the rotary shaft (90) and the farthermost point (33a) of the first blade housing hole (33) from the center (X) of the rotary shaft (90) as a line of symmetry. The direction in which the specific straight line (SL) extends matches the direction in which the first blade (38) extends, when the first piston (35) is located at top dead center. The specific straight line (SL) corresponds to a straight line extending in the direction in which the first blade (38) extends, when the first piston (35) is located at top dead center. The specific straight line (SL) is also a line of symmetry of the outer shape of the first cylinder (31).

[0095] As viewed in the axial direction, the first bolt (B1) and the second bolt (B2) are arranged line-symmetrically with respect to a straight line extending in the direction in which the first blade (38) extends, when the first piston (35) is located at top dead center. That is, as viewed in the axial direction, the first bolt (B1) and the second bolt (B2) are arranged line-symmetrically with respect to the specific straight line (SL) passing through the center (X) of the rotary shaft (90). When the first piston (35) is located at top dead center, the shortest distance from the center (BC1) of the first bolt (B1) to the first blade (38) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the first blade (38). The shortest distance from the center (BC1) of the first bolt (B1) to the first cylinder chamber (S1) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the first cylinder chamber (S1).

[0096] As shown in FIG. 9, as viewed in the axial direction, a first distance (D1) from the center (X) of the rotary shaft (90) to the farthermost point (33a) of the first blade housing hole (33) is greater than the second distance (D2) from the center (X) of the rotary shaft (90) to the center (BC1) of the first bolt (B1). In addition, as viewed in the axial direction, the first distance (D1) is greater than the third distance (D3) from the center (X) of the rotary shaft (90) to the center (BC2) of the second bolt (B2). In this embodiment, the second distance (D2) and the third distance (D3) are equal.

[0097] The third bolt (B3) to the seventh bolt (B7) are arranged in the order of the third bolt (B3), the fourth bolt (B4), the fifth bolt (B5), the sixth bolt (B6), and the seventh bolt (B7) clockwise from the first bolt (B1) as viewed from above in the axial direction. As shown in FIG. 8, as viewed in the axial direction, the third bolt (B3) is located closer to the suction pipe (14) than the first blade housing hole (33) is with the suction pipe (14) interposed between the first bolt (B1) and the third bolt (B3). The seventh bolt (B7) is disposed at a position farther from the first blade housing hole (33) than the imaginary line (IL) is.

[0098] The first bolt (B1) to the seventh bolt (B7) are arranged at relatively equal intervals, while avoiding the suction pipe (14), the injection pipe, and the discharge valve (53, 59). As shown in FIG. 9, a first interval (W1) represents the interval between the center (BC1) of the first bolt (B1) and the center (BC2) of the second bolt (B2), a second interval (W2) represents the interval between the center (BC2) of the second bolt (B2) and the center (BC3) of the third bolt (B3), a third interval (W3) represents the interval between the center (BC3) of the third bolt (B3) and the center (BC4) of the fourth bolt (B4), a fourth interval (W4) represents the interval between the center (BC4) of the fourth bolt (B4) and the center (BC5) of the fifth bolt (B5), a fifth interval (W5) represents the interval between the center (BC5) of the fifth bolt (B5) and the center (BC6) of the sixth bolt (B6), a sixth interval (W6) represents the interval between the center (BC6) of the sixth bolt (B6) and the center (BC7) of the seventh bolt (B7), and a seventh interval (W7) represents the interval between the center (BC7) of the seventh bolt (B7) and the center (BC2) of the second bolt (B2). The fifth interval (W5) is the narrowest and the seventh interval (W7) is the widest. The ratios of the intervals (W2, W3, W4, W5, W6, W7) to the first interval (W1) are within a range from 0.85 to 1.50. Specifically, the ratio of the second interval (W2) to the first interval (W1) is 0.96. The ratio of the third interval (W3) to the first interval (W1) is 0.97. The ratio of the fourth interval (W4) to the first interval (W1) is 1.00. The ratio of the fifth interval (W5) to the first interval (W1) is 0.89. The ratio of the sixth interval (W6) to the first interval (W1) is 1.14. The ratio of the seventh interval (W7) to the first interval (W1) is 1.43. The ratio of the seventh interval (W7), which is the widest, to the fifth interval (W5), which is the narrowest, is less than 2.00, specifically, 1.61.(5) Advantages of Embodiments

[0099] In the rotary compressor (1) according to this embodiment, the cylinder (31, 41), the front head (50), the middle plate (55), and the rear head (56) are fixed to each other by the plurality of bolts (B) extending in the axial direction of the rotary shaft (90). The plurality of bolts (B) include: the first bolt (B1) between the suction pipe (14) and the blade housing hole (33, 43) housing the blade (38, 48) as viewed in the axial direction; and the second bolt (B2) between the blade housing hole (33, 43) and the imaginary line (IL), which is symmetrical to the center line (AL) of the suction pipe (14) with respect to the blade housing hole (33, 43), as viewed in the axial direction. The first bolt (B1) and the second bolt (B2) are arranged on the opposite sides of the blade housing hole (33, 43) near the blade housing hole (33, 43). This configuration can facilitate balancing of the axial forces of the bolts (B) near the blade housing hole (33, 43). Accordingly, the rotary compressor (1) according to this embodiment can set the axial gaps between the front head (50), the middle plate (55), and the rear head (56) and the blade (38, 48) or between the front head (50), the middle plate (55), and the rear head (56) and the piston (35, 45) to appropriate sizes, thereby improving the compression efficiency.

[0100] In the rotary compressor (1) according to this embodiment, as viewed in the axial direction, the first distance (D1) from the center (X) of the rotary shaft (90) to the farthermost point of the blade housing hole (33, 43) from the center (X) of the rotary shaft (90) is longer than the second distance (D2) from the center (X) of the rotary shaft (90) to the center (BC1) of the first bolt (B1). As viewed in the axial direction, the first distance (D1) is longer than a third distance (D3) from the center (X) of the rotary shaft (90) to the center (BC2) of the second bolt (B2). The first bolt (B1) and the second bolt (B2) can be arranged close to the cylinder chamber (S1, S2). Accordingly, the rotary compressor (1) according to this embodiment can set the axial gaps between the front head (50), the middle plate (55), and the rear head (56) and the blade (38, 48) or between the front head (50), the middle plate (55), and the rear head (56) and the piston (35, 45) in the cylinder chamber (S1, S2) to appropriate sizes, thereby improving the compression efficiency.

[0101] In the rotary compressor (1) according to this embodiment, as viewed in the axial direction, the first bolt (B1) and the second bolt (B2) are arranged line-symmetrically with respect to, as a line of symmetry, the specific straight line (SL) extending in a direction in which the blade (38, 48) extends when the piston (35, 45) is located at top dead center. When the first piston (35) is located at top dead center, the shortest distance from the center (BC1) of the first bolt (B1) to the blade (38, 48) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the blade (38, 48). Accordingly, the rotary compressor (1) according to this embodiment can facilitate balancing of the axial forces of the bolts (B) near the blade (38, 48), thereby improving the compression efficiency.

[0102] In the rotary compressor (1) according to this embodiment, the specific straight line (SL) is a straight line passing through the center (X) of the rotary shaft (90). Accordingly, the second distance (D2) and the third distance (D3) are equal to each other, and thus the shortest distance from the center (BC1) of the first bolt (B1) to the cylinder chamber (S1, S2) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the cylinder chamber (S1, S2). Accordingly, the influence of the axial force of the first bolt (B1) and the influence of the axial force of the second bolt (B2) on the cylinder chamber (S1, S2) become equal. The rotary compressor (1) according to this embodiment can facilitate balancing of the axial forces of the bolts (B) near the blade (38, 48) in the cylinder chamber (S1, S2), thereby improving the compression efficiency.

[0103] In the rotary compressor (1) according to this embodiment, the plurality of bolts (B) further include: a third bolt (B3) closer to the suction pipe (14) than the blade housing hole (33, 43) is with the suction pipe (14) interposed between the first bolt (B1) and the third bolt (B3) as viewed in the axial direction. The second bolt (B2) is disposed with the blade housing hole (33, 43) interposed between the first bolt (B1) and the second bolt (B2). The third bolt (B3) is disposed with the suction pipe (14) interposed between the first bolt (B1) and the third bolt (B3). Accordingly, the first interval (W1) between the center (BC1) of the first bolt (B1) and the center (BC2) of the second bolt (B2) and the second interval (W2) between the center (BC1) of the first bolt (B1) and the center (BC3) of the third bolt (B3) can be substantially equal to each other. Accordingly, the rotary compressor (1) according to this embodiment can facilitate balancing of the axial forces of the bolts (B) near the blade (38, 48), thereby improving the compression efficiency.

[0104] In the rotary compressor (1) according to this embodiment, the ratios of the interval between the centers of the bolts (B) adjacent to each other in the circumferential direction to first interval (W1) between the center (BC1) of the first bolt (B1) and the center (BC2) of the second bolt (B2) is within the range from 0.85 to 1.50. Since the interval between the centers of the bolts (B) adjacent to each other in the circumferential direction can be made substantially equal, the amount of deformation due to the axial forces of the bolts (B) can be reduced in the cylinder (31, 41) as a whole. Accordingly, the rotary compressor (1) according to this embodiment can set the axial gaps between the front head (50), the middle plate (55), and the rear head (56) and the blade (38, 48) or between the front head (50), the middle plate (55), and the rear head (56) and the piston (35, 45) to appropriate sizes, thereby improving the compression efficiency.

[0105] In the rotary compressor (1) according to this embodiment, the suction port (17, 18) extends to a position closer to the blade housing hole (33, 43) than the suction pipe (14) is and is inclined with respect to the direction of insertion of the suction pipe (14). Accordingly, the rotary compressor (1) according to this embodiment supplies the refrigerant at a point closer to top dead center, thereby improving the compression efficiency.(6) Variations

[0106] The above embodiment may be modified as the following variations. In the following description, the differences from the embodiment will be described in principle.(6-1) First Variation

[0107] In a rotary compressor (1) according to the first variation, the positional relationship between the first bolt (B1) and the second bolt (B2) is different from that of the embodiment described above. Specifically, as shown in FIG. 10, in the rotary compressor (1) according to the first variation, the first bolt (B1) is disposed more outward than the second bolt (B2) is in the radial direction. As in the embodiment described above, since the bolts (B) are arranged in the same manner in both the first cylinder (31) and the second cylinder (41), the first cylinder (31) will be described as a reference in the following.

[0108] Since the first bolt (B1) is disposed as described above, the second distance (D2) from the center (X) of the rotary shaft (90) to the center (BC1) of the first bolt (B1) differs from the third distance (D3) from the center (X) of the rotary shaft (90) to the center (BC2) of the second bolt (B2). Specifically, the second distance (D2) is longer than the third distance (D3). Accordingly, the shortest distance from the first bolt (B1) to the first cylinder chamber (S1) is longer than the shortest distance from the second bolt (B2) to the first cylinder chamber (S1).

[0109] The shortest distance (SD1) from the center (BC1) of the first bolt (B1) to the specific straight line (SL) is equal to the shortest distance (SD2) from the center (BC2) of the second bolt (B2) to the specific straight line (SL). Accordingly, when the first piston (35) is located at top dead center, the shortest distance from the center (BC1) of the first bolt (B1) to the first blade (38) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the first blade (38).

[0110] In the rotary compressor (1) according to the first variation, the portion of the cylinder (31, 41) around the suction port (17, 18) is cooled by the refrigerant and thermally contracts. When the cylinder (31, 41) thermally contracts, the gaps between the front head (50), the middle plate (55), and the rear head (56) and the piston (35, 45) and between the front head (50), the middle plate (55), and the rear head (56) and the blade (38, 48) become small, and the seizing may occur. In the rotary compressor (1) according to the first variation, the first bolt (B1) can be spaced apart from the cylinder chamber (S1, S2). This can reduce the amount of deformation of a suction-side portion of the cylinder (31, 41, 231, 241, 331) by the axial forces of the bolts. Accordingly, the rotary compressor (1) according to the first variation can set the gaps between the front head (50), the middle plate (55), and the rear head (56) and the blade (38, 48) or between the front head (50), the middle plate (55), and the rear head (56) and the piston (35, 45) in the cylinder chamber (S1, S2) to appropriate sizes, thereby reducing the seizing.

[0111] In the rotary compressor (1) according to the first variation, when the piston (35, 45) is located at top dead center, the shortest distance from the center (BC1) of the first bolt (B1) to the blade (38, 48) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the blade (38, 48). Accordingly, the rotary compressor (1) according to this variation can facilitate balancing of the axial forces of the bolts (B) near the blade (38, 48), thereby improving the compression efficiency.(6-2) Second Variation

[0112] In a rotary compressor (1) according to the second variation, the positional relationship between the first bolt (B1) and the second bolt (B2) differs from that of the embodiment described above. Specifically, as shown in FIG. 11, in the rotary compressor (1) according to the second variation, the second bolt (B2) is disposed more outward than the first bolt (B1) is in the radial direction. As in the embodiment described above, since the bolts (B) are arranged in the same manner in both the first cylinder (31) and the second cylinder (41), the first cylinder (31) will be described as a reference in the following.

[0113] Since the second bolt (B2) is disposed as described above, the second distance (D2) from the center (X) of the rotary shaft (90) to the center (BC1) of the first bolt (B1) differs from the third distance (D3) from the center (X) of the rotary shaft (90) to the center (BC2) of the second bolt (B2). Specifically, the third distance (D3) is longer than the second distance (D2). Accordingly, the shortest distance from the second bolt (B2) to the first cylinder chamber (S1) is longer than the shortest distance from the first bolt (B1) to the first cylinder chamber (S1).

[0114] The shortest distance (SD1) from the center (BC1) of the first bolt (B1) to the specific straight line (SL) is equal to the shortest distance (SD2) from the center (BC2) of the second bolt (B2) to the specific straight line (SL). Accordingly, when the first piston (35) is located at the top dead center, the shortest distance from the center (BC1) of the first bolt (B1) to the first blade (38) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the first blade (38).

[0115] In the rotary compressor (1) according to the second variation, the front head (50), the middle plate (55), and the rear head (56) are thermally expanded by the compressed high-temperature refrigerant around the discharge port (51, 57) of the cylinder (31, 41). When these thermally expand, the gaps between the front head (50), the middle plate (55), and the rear head (56) and the piston (35, 45) and between the front head (50), the middle plate (55), and the rear head (56) and the blade (38, 48) become small, and the seizing may occur. In the rotary compressor (1) according to the second variation, the second bolt (B2) can be spaced apart from the cylinder chamber (S1, S2). This can reduce the amount of deformation of a discharge-side portion of the cylinder (31, 41, 231, 241, 331) by the axial forces of the bolts. Accordingly, the rotary compressor (1) according to the first variation can set the gaps between the front head (50), the middle plate (55), and the rear head (56) and the blade (38, 48) or between the front head (50), the middle plate (55), and the rear head (56) and the piston (35, 45) in the cylinder chamber (S1, S2) to appropriate sizes, thereby reducing the seizing.

[0116] In the rotary compressor (1) according to the second variation, when the piston (35, 45) is located at top dead center, the shortest distance from the center (BC1) of the first bolt (B1) to the blade (38, 48) is equal to the shortest distance from the center (BC2) of the second bolt (B2) to the blade (38, 48). Accordingly, the rotary compressor (1) according to the second variation can facilitate balancing of the axial forces of the bolts (B) near the blade (38, 48), thereby improving the compression efficiency.<Other Embodiments>

[0117] The suction pipe (14) may be disposed in any of the front head (50), the middle plate (55), the first cylinder (31), and the second cylinder (41).

[0118] As shown in FIG. 12, a compression mechanism (230) of a rotary compressor (201) may have two suction pipes, namely, a first suction pipe (214a) and a second suction pipe (214b). In FIG. 12, the first suction pipe (214a) is connected to a first suction port (217) of a first cylinder (231). The second suction pipe (214b) is connected to a second suction port (218) of a second cylinder (241). In the example shown in FIG. 12, the suction passage as in the embodiment described above is not provided, and the suction port (217, 218) is directly connected to the suction pipe (214a, 214b). The first suction pipe (214a) may be disposed in a front head (250), and the second suction pipe (214b) may be disposed in a rear head (256). One or both of the first suction pipe (214a) and the second suction pipe (214b) may be disposed in a middle plate (255). In these cases, there is a need to provide a suction passage.

[0119] As shown in FIG. 13, a compression mechanism (330) of a rotary compressor (301) may be of a single-cylinder type including one piston (35) and one eccentric portion (91). In the example shown in FIG. 13, a suction pipe (314) is inserted into an insertion hole (319) of a rear head (356). The suction pipe (314) is connected to a suction port (317) via a suction passage

[0120] (316) formed in the rear head (356) and a cylinder (331). The suction pipe (314) may be disposed in either a front head (350) or the cylinder (331).

[0121] The rotary compressor (1) may be of a so-called rolling piston type in which a piston eccentrically rotates while a blade separate from the piston abuts on the piston, or may be of a so-called hinge vane type in which a piston eccentrically rotates with a tip of a blade rotatably fitted into a recess of the outer circumferential surface of the piston.

[0122] While the embodiments and variations thereof have been described above, it will be understood that various changes in form and details may be made without departing from the spirit and scope of the claims. The embodiments, the variation thereof, and the other embodiments may be combined and replaced with each other without deteriorating intended functions of the present disclosure.

[0123] 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

[0124] As described above, the present disclosure is useful for a rotary compressor.DESCRIPTION OF REFERENCE CHARACTERS

[0125] 1Rotary Compressor 31First Cylinder 35First Piston 38First Blade 41Second Cylinder 45Second Piston 48Second Blade 50Front Head (Closing Member) 55Middle Plate (Closing Member) 56Rear Head (Closing Member) 201Rotary Compressor 231First Cylinder 241Second Cylinder 250Front Head (Closing Member) 255Middle Plate (Closing Member) 256Rear Head (Closing Member) 301Rotary Compressor 331Cylinder 350Front Head (Closing Member) 356Rear Head (Closing Member) B1First Bolt BC1Center of First Bolt B2Second Bolt BC2Center of Second Bolt B3Third Bolt ALCenter Line of Suction Pipe ILImaginary Line XCenter of Rotary Shaft

Claims

1. A rotary compressor, comprising: a cylinder (31, 41, 231, 241, 331) having a cylinder chamber (S1, S2) therein; a piston (35, 45) configured to turn along an inner surface of the cylinder chamber (S1, S2); a rotary shaft (90) configured to turn the piston (35, 45); a blade (38, 48) configured to divide the cylinder chamber (S1, S2) into a suction space (71, 75) and a discharge space (72, 76); a closing member (50, 55, 56, 250, 255, 256, 350, 356) configured to close an end of the cylinder chamber (S1, S2) in an axial direction of the rotary shaft (90); and a suction pipe (14, 214a, 214b, 314) configured to supply a refrigerant to the suction space (71, 75), the cylinder (31, 41, 231, 241, 331) and the closing member (50, 55, 56, 250, 255, 256, 350, 356) being fixed to each other by a plurality of bolts (B) extending in the axial direction of the rotary shaft (90), the plurality of bolts (B) including: a first bolt (B1) between the suction pipe (14, 214a, 214b, 314) and a housing (33, 43) housing the blade (38, 48), as viewed in the axial direction; and a second bolt (B2) between the housing (33, 43) and an imaginary line (IL) that is symmetrical to a center line (AL) of the suction pipe (14, 214a, 214b, 314) with respect to the housing (33, 43), as viewed in the axial direction.

2. The rotary compressor of claim 1, wherein the plurality of bolts (B) further include: a third bolt (B3) disposed closer to the suction pipe (14) than the housing (33, 43) is so that the suction pipe (14, 214a, 214b, 314) is interposed between the first bolt (B1) and the third bolt (B3), as viewed in the axial direction.

3. The rotary compressor of claim 1 or 2, wherein as viewed in the axial direction, a first distance (D1) from a center (X) of the rotary shaft (90) to a farthermost point of the housing (33, 43) from the center (X) of the rotary shaft (90) is longer than a second distance (D2) from the center (X) of the rotary shaft (90) to a center (BC1) of the first bolt (B1), and as viewed in the axial direction, the first distance (D1) is longer than a third distance (D3) from the center (X) of the rotary shaft (90) to a center (BC2) of the second bolt (B2).

4. The rotary compressor of any one of claims 1 to 3, wherein as viewed in the axial direction, the first bolt (B1) and the second bolt (B2) are arranged line-symmetrically with respect to a straight line extending in a direction in which the blade (38, 48) extends when the piston (35, 45) is located at top dead center.

5. The rotary compressor of any one of claims 1 to 3, wherein as viewed in the axial direction, a second distance (D2) from the center (X) of the rotary shaft (90) to a center (BC1) of the first bolt (B1) is longer than a third distance (D3) from the center (X) of the rotary shaft (90) to a center (BC2) of the second bolt (B2).

6. The rotary compressor of any one of claims 1 to 3, wherein as viewed in the axial direction, a third distance (D3) from the center (X) of the rotary shaft (90) to a center (BC2) of the second bolt (B2) is longer than a second distance (D2) from the center (X) of the rotary shaft (90) to a center (BC1) of the first bolt (B1).

7. The rotary compressor of any one of claims 1 to 6, wherein the suction pipe (14, 214a, 214b, 314) is disposed in the closing member (50, 55, 56, 250, 255, 256, 350, 356), the cylinder (31, 41, 231, 241, 331) has a suction port (17, 18) through which the refrigerant supplied from the suction pipe (14, 214a, 214b, 314) is supplied to the suction space (71, 75), and as viewed in the axial direction, the suction port (17, 18) extends to a position closer to the housing (33, 43) than the suction pipe (14, 214a, 214b, 314) is and is inclined with respect to a direction of insertion of the suction pipe (14, 214a, 214b, 314).

8. The rotary compressor of any one of claims 1 to 7, wherein the refrigerant is carbon dioxide.

9. A refrigeration apparatus comprising: the rotary compressor (1) of any one of claims 1 to 8.

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