Rotary compressor and refrigeration apparatus

Abstract

A drive shaft (25) has a main shaft portion (26) and an eccentric portion (27). The drive shaft (25) has an oil passage (30). The oil passage (30) includes one or more oil holes (31) extending in an axial direction. As viewed in the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a phantom envelope (40) that envelops the one or more oil holes (31) is referred to as a first direction (Y), and a direction orthogonal to the first direction (Y) is referred to as a second direction (X). As viewed in the axial direction, the oil passage (30) has a length in the first direction (Y) that is greater than a length in the second direction (X) in the region surrounded by the phantom envelope (40).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a rotary compressor and a refrigeration apparatus.BACKGROUND ART

[0002] Patent Document 1 discloses a compressor including: a compression mechanism having a rolling piston; and a drive shaft (shaft) that eccentrically rotates the rolling piston. The drive shaft has an oil passage (center hole) extending in an axial direction. Refrigerating machine oil stored at the bottom of a closed container is supplied through the oil passage to sliding portions.CITATION LISTPATENT DOCUMENT

[0003] [Patent Document 1] Japanese Patent No. 7003305SUMMARY OF THE INVENTIONTECHNICAL PROBLEM

[0004] Here, centrifugal force and gas load are applied to the drive shaft as the compression mechanism is driven and rotates, resulting in an increase in the shaft deflection of the drive shaft.

[0005] To address this, the inventors of this application have focused on the oil passage that is a cause of lower rigidity of the drive shaft, and have studied how to increase the rigidity of the drive shaft through improvement in the shape of the oil passage.

[0006] An object of the present disclosure is to reduce shaft deflection of a drive shaft through improvement in the shape of an oil passage.SOLUTION TO THE PROBLEM

[0007] A first aspect of the present disclosure is directed to a rotary compressor including: a compression mechanism (50); and a drive shaft (25) configured to rotationally drive the compression mechanism (50), the drive shaft (25) including a main shaft portion (26) and an eccentric portion (27), the eccentric portion (27) being eccentric with respect to an axis (C1) of the main shaft portion (26) by a predetermined distance, the drive shaft (25) having an oil passage (30) including one or more oil holes (31) extending in an axial direction, as viewed in the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a phantom envelope (40) that envelops the one or more oil holes (31) being referred to as a first direction (Y), a direction orthogonal to the first direction (Y) being referred to as a second direction (X), as viewed in the axial direction, the oil passage (30) has a length in the first direction (Y) that is greater than a length in the second direction (X) in the region surrounded by the phantom envelope (40).

[0008] According to the first aspect, the rigidity of the drive shaft (25) can be increased, thereby reducing shaft deflection, by forming the oil passage (30) such that the length in the first direction (Y) is greater than the length in the second direction (X) in the region surrounded by the phantom envelope (40).

[0009] Specifically, to suck up oil by centrifugal pumping action, a centrifugal pump needs to structurally include a small-diameter portion located near its inlet and a large-diameter portion located near its outlet, the large-diameter portion having a greater diameter than the small-diameter portion.

[0010] In known rotary compressors, the small-diameter portion of the centrifugal pump near the inlet corresponds to a tapered suction port that is open to a lower end portion of the centrifugal pump, and the large-diameter portion near the outlet corresponds to a circular oil passage extending in the axial direction through a central portion of the drive shaft (25). Thus, in known rotary compressors, a circular oil passage having a relatively large diameter corresponding to the length in the first direction (Y) is formed in the central portion of the drive shaft (25), which may reduce the rigidity of the drive shaft (25).

[0011] In contrast, by setting the length of the oil passage (30) in the second direction (X) to be shorter than the length in the first direction (Y), the area of the oil passage (30) can be made smaller than that of a circular oil passage provided at the central portion of the drive shaft (25), thereby improving the rigidity of the drive shaft (25) and reducing the shaft deflection.

[0012] Further, by setting the distance from the center of rotation of the drive shaft (25) to the inner wall surface of the oil passage (30) at a point farthest from the center of rotation in the radial direction to be equivalent to the radius of a circular oil passage, an equivalent centrifugal pumping action can be obtained.

[0013] A second aspect of the present disclosure is an embodiment of the rotary compressor of the first aspect. In the second aspect, the first direction (Y) is a direction that connects the axis (C1) of the main shaft portion (26) and an axis (C2) of the eccentric portion (27), as viewed in the axial direction of the drive shaft (25).

[0014] According to the second aspect, the rigidity of the drive shaft (25) in the second direction (X) is higher than the rigidity in the first direction (Y). Thus, the shaft deflection of the drive shaft (25) can be reduced even if the maximum gas load during the rotational driving of the compression mechanism (50) is applied to the drive shaft (25) in the second direction (X).

[0015] A third aspect of the present disclosure is an embodiment of the rotary compressor of the first or second aspect. In the third aspect, the oil passage (30) is formed as a long oil hole (31) extending along the first direction (Y) as viewed in the axial direction.

[0016] According to the third aspect, by forming the oil passage (30) as the long oil hole (31) extending along the first direction (Y) as viewed in the axial direction, the rigidity of the drive shaft (25) in the second direction (X) can be higher than the rigidity in the first direction (Y).

[0017] A fourth aspect of the present disclosure is an embodiment of the rotary compressor of the first or second aspect. In the fourth aspect, the oil passage (30) is formed by the plurality of oil holes (31) arranged along the first direction (Y) as viewed in the axial direction.

[0018] According to the fourth aspect, by forming the oil passage (30) as a plurality of oil holes (31) arranged along the first direction (Y), the rigidity of the drive shaft (25) in the second direction (X) can be higher than the rigidity in the first direction (Y).

[0019] A fifth aspect of the present disclosure is an embodiment of the rotary compressor of the fourth aspect. In the fifth aspect, in the oil passage (30), the plurality of oil holes (31) is arranged so that the oil holes (31) adjacent to each other partially overlap each other as viewed in the axial direction.

[0020] According to the fifth aspect, assuming that the length in the first direction (Y) of the region surrounded by the phantom envelope (40) is constant, the number of oil holes (31) in the region surrounded by the phantom envelope (40) is greater when adjacent oil holes (31) partially overlap with each other than when adjacent oil holes (31) are spaced apart from each other. Thus, machining the oil passage (30) into a long-hole shape becomes easier.

[0021] A sixth aspect of the present disclosure is an embodiment of the rotary compressor of any one of the first to fifth aspects, further including: a motor (21) configured to rotate the drive shaft (25), wherein the compression mechanism (50) is disposed below the motor (21).

[0022] According to the sixth aspect, the oil passage (30) having a shape in which the length in the first direction (Y) is greater than the length in the second direction (X) in the region surrounded by the phantom envelope (40) is applicable to a rotary compressor in which the compression mechanism (50) is arranged below the motor (21).

[0023] A seventh aspect of the present disclosure is directed to a refrigeration apparatus including: the rotary compressor (10) of any one of the first to sixth aspects; and a refrigerant circuit (1a) through which a refrigerant compressed by the rotary compressor (10) flows.

[0024] According to the seventh aspect, it is possible to provide a refrigeration apparatus including the rotary compressor (10) and the refrigerant circuit (1a).BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [FIG. 1] FIG. 1 is a refrigerant circuit diagram illustrating a configuration of a refrigeration apparatus according to a first embodiment. [FIG. 2] FIG. 2 is a longitudinal sectional view illustrating a configuration of a rotary compressor. [FIG. 3] FIG. 3 is a transverse sectional view illustrating the configuration of the rotary compressor. [FIG. 4] FIG. 4 is a diagram illustrating a drive shaft as viewed in an axial direction. [FIG. 5] FIG. 5 is a cross-sectional view of the drive shaft taken along line A-A shown in FIG. 2. [FIG. 6] FIG. 6 is a diagram illustrating second moment of area in a situation where load is applied to a main shaft portion of the drive shaft in a first direction. [FIG. 7] FIG. 7 is a diagram illustrating second moment of area in a situation where load is applied to a main shaft portion of the drive shaft in a second direction. [FIG. 8] FIG. 8 is a graph showing the relationship between an angle from the top dead center and the magnitude of force applied to the drive shaft. [FIG. 9] FIG. 9 is a graph showing the relationship between an angle from the top dead center and the direction of force applied to the drive shaft. [FIG. 10] FIG. 10 is a graph showing the relationship between an angle from the top dead center, and the direction of force applied to the drive shaft when the direction of eccentricity of an eccentric portion is taken as a reference 0°. [FIG. 11] FIG. 11 is a diagram illustrating the angle at which a maximum gas load is applied to the drive shaft. [FIG. 12] FIG. 12 is a diagram illustrating a drive shaft of a second embodiment as viewed in an axial direction. [FIG. 13] FIG. 13 is a diagram illustrating a drive shaft of a third embodiment as viewed in an axial direction. [FIG. 14] FIG. 14 is a diagram illustrating a drive shaft of a fourth embodiment as viewed in an axial direction. [FIG. 15] FIG. 15 is a diagram illustrating a drive shaft of a fifth embodiment as viewed in an axial direction. [FIG. 16] FIG. 16 is a longitudinal sectional view illustrating a configuration of a rotary compressor according to a sixth embodiment. [FIG. 17] FIG. 17 is a diagram illustrating a configuration of a drive shaft as viewed in an axial direction. DESCRIPTION OF EMBODIMENTS«First Embodiment»

[0026] As illustrated in FIG. 1, a rotary compressor (10) is provided in a refrigeration apparatus (1). The refrigeration apparatus (1) includes a refrigerant circuit (1a) filled with a refrigerant. The refrigerant circuit (1a) includes the rotary compressor (10), a radiator (3), a decompression mechanism (4), and an evaporator (5). The decompression mechanism (4) is, for example, an expansion valve. The refrigerant circuit (1a) performs a vapor compression refrigeration cycle.

[0027] The refrigeration apparatus (1) is an air conditioner. The air conditioner may be any of a cooling-only apparatus, a heating-only apparatus, or an air conditioner switchable between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., a four-way switching valve) configured to switch the direction of circulation of the refrigerant. The refrigeration apparatus (1) may be a water heater, a chiller unit, or a cooling apparatus configured to cool air in an internal space. The cooling apparatus cools the air in an internal space of a refrigerator, a freezer, a container, or the like.

[0028] As illustrated in FIG. 2, the rotary compressor (10) includes a casing (11), a drive mechanism (20), and a compression mechanism (50).

[0029] The casing (11) is configured as a vertically long cylindrical closed container. A suction pipe (16) passes through, and is fixed to, the barrel of the casing (11). An accumulator (not shown) is connected to the suction pipe (16). A discharge pipe (17) passes through, and is fixed to, an upper portion of the casing (11).

[0030] The casing (11) has an oil reservoir (18) at its bottom. The oil reservoir (18) stores oil. The oil is used to lubricate sliding portions of the compression mechanism (50) and a drive shaft (25).<Drive Mechanism>

[0031] The drive mechanism (20) is housed in the casing (11). The drive mechanism (20) includes a motor (21) and the drive shaft (25). The motor (21) is disposed above the compression mechanism (50). The motor (21) includes a stator (22) and a rotor (23).

[0032] The stator (22) is fixed to the inner circumferential surface of the casing (11). The rotor (23) passes through the stator (22) in the up-and-down direction. The drive shaft (25) is fixed inside the axial center of the rotor (23). The drive shaft (25) is driven to rotate together with the rotor (23) when the motor (21) is energized.

[0033] The drive shaft (25) is arranged on the axis of the casing (11). An oil passage (30) is formed inside the drive shaft (25). A centrifugal oil supply pump (28) is provided at the lower end of the drive shaft (25). A lower portion of the oil supply pump (28) has an intake port (28a). The oil supply pump (28) conveys the oil stored in the oil reservoir (18). The conveyed oil is supplied to the sliding portions of the compression mechanism (50) and the drive shaft (25) through the oil passage (30) in the drive shaft (25).

[0034] The drive shaft (25) has a main shaft portion (26) and an eccentric portion (27). An upper portion of the main shaft portion (26) is fixed to the rotor (23) of the motor (21). The eccentric portion (27) has an axis decentered by a predetermined distance with respect to the axis of the main shaft portion (26).

[0035] Part of the main shaft portion (26) above the eccentric portion (27) is rotatably supported by a front head (52) described later. Part of the main shaft portion (26) below the eccentric portion (27) is rotatably supported by a rear head (53) described later.<Compression Mechanism>

[0036] The compression mechanism (50) is housed in the casing (11). The compression mechanism (50) is disposed below the motor (21). The compression mechanism (50) includes a cylinder (51), the front head (52), the rear head (53), and a piston (54).

[0037] The cylinder (51) is formed as a flat and substantially annular member. The cylinder (51) has a circular compression chamber (55) at its center. The cylinder (51) has a suction passage (56) extending in a radial direction. The downstream end of the suction passage (56) communicates with the compression chamber (55). The suction pipe (16) is connected to the upstream end of the suction passage (56).

[0038] The front head (52) is disposed on an upper portion of the cylinder (51). The front head (52) covers the internal space of the cylinder (51) from above. The front head (52) rotatably supports the main shaft portion (26) of the drive shaft (25). The front head (52) has a discharge passage (not shown) passing therethrough in the axial direction.

[0039] The rear head (53) is disposed on a lower portion of the cylinder (51). The rear head (53) covers the internal space of the cylinder (51) from below. The rear head (53) rotatably supports the main shaft portion (26) of the drive shaft (25).

[0040] As illustrated also in FIG. 3, the piston (54) is housed in the cylinder (51). A blade (57) is integrated with the piston (54). The compression chamber (55) is defined by the cylinder (51) and the piston (54). The piston (54) has a perfectly circular annular shape. The eccentric portion (27) of the drive shaft (25) is fitted in the piston (54).

[0041] The interior of the compression chamber (55) is partitioned into a low-pressure chamber (55a) and a high-pressure chamber (55b) by the blade (57) (see FIG. 11). The blade (57) is supported by a pair of bushes (58), which allow oscillation of the blade (57).

[0042] The piston (54) rotates eccentrically in the cylinder (51) when the drive shaft (25) is driven to rotate. The refrigerant flowing through the suction pipe (16) is sucked into the low-pressure chamber (55a) through the suction passage (56) as the volume of the low-pressure chamber (55a) is gradually increased by the eccentric rotation of the piston (54).

[0043] Next, the low-pressure chamber (55a) is isolated from the suction passage (56), and the isolated space forms the high-pressure chamber (55b). The internal pressure of the high-pressure chamber (55b) increases as the volume of the high-pressure chamber (55b) gradually decreases. When the internal pressure of the high-pressure chamber (55b) exceeds a predetermined pressure, the refrigerant in the high-pressure chamber (55b) flows out of the compression mechanism (50) through a discharge passage (59). The high-pressure refrigerant flows upward through the internal space of the casing (11) and passes through a core cut (not shown) of the motor (21) or any other passage. The high-pressure refrigerant that has flowed upward of the motor (21) is transferred to the refrigerant circuit (1a) through the discharge pipe (17).<Oil Passage>

[0044] Centrifugal force and gas load are applied to the drive shaft (25) as the compression mechanism (50) is driven and rotates, resulting in an increase in the shaft deflection of the drive shaft (25).

[0045] To address this, the inventors of this application have focused on the oil passage (30) that is a cause of lower rigidity of the drive shaft (25), and have studied how to increase the rigidity of the drive shaft (25) through improvement in the shape of the oil passage (30).

[0046] As illustrated in FIG. 2, the drive shaft (25) has the oil passage (30). The oil passage (30) includes an oil hole (31), a lower end hole (35), and lateral holes (36).

[0047] The lower end hole (35) is open at a lower end portion of the main shaft portion (26) of the drive shaft (25). The oil supply pump (28) is attached to the lower end hole (35). The oil hole (31) communicates with the lower end hole (35) and extends upward. The lateral holes (36) communicate with the oil hole (31) and extend in the horizontal direction. Each lateral hole (36) opens at a location that allows oil to be supplied to sliding portions of the compression mechanism (50) and the drive shaft (25).

[0048] In the example shown in FIG. 2, the lateral holes (36) are open to the sliding surfaces of the front head (52), the rear head (53), and the piston (54). A vent hole (37) is formed in a portion of the drive shaft (25) above the front head (52). The vent hole (37) discharges gas contained in the oil passing through the oil passage (30).

[0049] The oil flowing through the oil hole (31) is discharged to the outside of the drive shaft (25) through the lateral holes (36) by centrifugal force generated by the rotation of the drive shaft (25), and is supplied to the sliding portions of the compression mechanism (50) and the drive shaft (25).

[0050] As illustrated in FIG. 4, the axis of the main shaft portion (26) is referred to as the axis (C1), and the axis of the eccentric portion (27) is referred to as the axis (C2). As viewed in the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a phantom envelope (40) that envelops the oil hole (31) is referred to as a first direction (Y), and a direction orthogonal to the first direction (Y) is referred to as a second direction (X).

[0051] In the example shown in FIG. 4, as viewed in the axial direction of the drive shaft (25), the direction that connects the axis (C1) of the main shaft portion (26) and the axis (C2) of the eccentric portion (27) is referred to as the first direction (Y), and the direction orthogonal to the first direction (Y) is referred to as the second direction (X), as non-limiting configurations.

[0052] The oil passage (30) is formed as a long oil hole (31) extending along the first direction (Y) as viewed in the axial direction. Here, the length of the oil hole (31) in the second direction (X) is referred to as x, and the length of the oil hole (31) in the first direction (Y) is referred to as y. The long oil hole (31) can be represented as a locus of a circle having a diameter x that is moved continuously in the first direction (Y). Here, a curve that is a tangent to all the circles is referred to as an "envelope." In the example shown in FIG. 4, a phantom envelope (40) that envelops the oil hole (31) as viewed in the axial direction is indicated by the phantom line. The phantom envelope (40) is represented as a curve in the form of a long hole extending along the inner peripheral edge of the oil hole (31).

[0053] As viewed in the axial direction, the oil passage (30) has the length y in the first direction (Y) that is greater than the length x in the second direction (X) in a region surrounded by the phantom envelope (40) that envelops the oil hole (31). This can improve the rigidity of the drive shaft (25) and reduce the shaft deflection.

[0054] Specifically, if the oil passage has a circular shape having a diameter corresponding to the length of the first direction (Y), is greater in hole diameter than the intake port (28a), and is provided at a central portion of the drive shaft (25) to suck up oil by a centrifugal pumping action, this indicates that the drive shaft (25) has a relatively large hollow portion in its central portion (see the region surrounded by the phantom line in FIG. 5), which may reduce the rigidity of the drive shaft (25).

[0055] In contrast, by setting the length of the oil passage (30) in the second direction (X) to be shorter than the length in the first direction (Y), the area of the oil passage (30) can be made smaller than that of a circular oil passage provided at the central portion of the drive shaft (25), thereby improving the rigidity of the drive shaft (25) and reducing the shaft deflection.

[0056] By making the distance from the center of rotation of the drive shaft (25) to the inner wall surface of the oil passage (30) at a point farthest from the center of rotation in the radial direction equivalent to the radius of a circular oil passage, an equivalent centrifugal pumping action can be obtained (see FIG. 5).

[0057] Further, by forming the oil passage (30) such that the length in the first direction (Y) is greater than the length in the second direction (X) in a region surrounded by the phantom envelope (40), it is possible to make the rigidity of the drive shaft (25) in the second direction (X) higher than the rigidity in the first direction (Y).

[0058] The relationship between the shape of the oil hole (31) and the bending rigidity of the drive shaft (25) will be described below with reference to FIG. 6 and FIG. 7. In FIG. 6 and FIG. 7, only the main shaft portion (26) of the drive shaft (25) is shown, and the eccentric portion (27) is not shown. For ease of description, the oil hole (31) is described not in the form of a long hole extending in the first direction (Y) but in the form of a rectangle close to the long hole and extending in the first direction (Y).

[0059] As illustrated in FIG. 6, the diameter of the main shaft portion (26) is referred to as D. When load is applied to the main shaft portion (26) of the drive shaft (25) in the first direction (Y), the second moment of area Iy is calculated by the following formula (1). Iy = π ⋅ D 4 / 64 − x ⋅ y 3 / 12

[0060] On the other hand, as illustrated in FIG. 7, when load is applied to the main shaft portion (26) of the drive shaft (25) in the second direction (X), the second moment of area Ix is calculated by the following formula (2). Ix = π ⋅ D 4 / 64 − y ⋅ x 3 / 12

[0061] Here, since "x < y" is satisfied, the value Iy including "y 3< " decreases more significantly than the value Ix including "y". That is, "Ix > Iy" is satisfied, which indicates the bending rigidity of the drive shaft (25) in the second direction (X) is higher than the bending rigidity in the first direction (Y).

[0062] Next, the relationship between the rotational angle of the drive shaft (25) and the load applied to the drive shaft (25) will be described with reference to the graphs of FIGS. 8 to 10. As illustrated in FIG. 3, the position at which the eccentric portion (27) of the drive shaft (25) is directed upward in FIG. 3 is referred to as the top dead center 0°.

[0063] FIG. 8 is a graph showing the relationship between an angle from the top dead center and the magnitude of force applied to the drive shaft (25). In the case of FIG. 8, a maximum gas load during the rotational driving of the compression mechanism (50) is applied to the drive shaft (25) at a position rotated 227° from the top dead center 0°.

[0064] FIG. 9 is a graph showing the relationship between an angle from the top dead center and the direction of force applied to the drive shaft (25). As shown in FIG. 9, the direction of the gas load applied to the drive shaft (25) is 119.18° (≈ 119°) at the position of 227°, which is an angle at which the maximum gas load is applied during the rotational driving of the compression mechanism (50).

[0065] FIG. 10 is a graph showing the relationship between an angle from the top dead center and the direction of gas load applied to the drive shaft (25) when the direction of eccentricity of the eccentric portion (27) is taken as a reference 0°. As shown in FIG. 10, when the direction of eccentricity of the eccentric portion (27) is taken as the reference 0°, the direction of the gas load applied to the drive shaft (25) is -107.82° (≈ -108°) at the position of 227°, which a rotational angle at which the maximum gas load is applied during the rotational driving of the compression mechanism (50).

[0066] FIG. 11 is a diagram illustrating the angle at which the maximum gas load is applied to the drive shaft (25). In FIG. 11, the maximum gas load during the rotational driving of the compression mechanism (50) is applied to the drive shaft (25) at the position rotated 227° from the top dead center 0°, in a direction rotated 108° counterclockwise from the first direction (Y) connecting the axis (C1) of the main shaft portion (26) and the axis (C2) of the eccentric portion (27). In FIG. 11, the load direction is indicated by the white arrow.

[0067] Here, the direction of the maximum gas load during the rotational driving of the compression mechanism (50) varies in the range of 80° to 110°, for example, depending on compression conditions or the like. The second direction (X) is the direction orthogonal to the first direction (Y), that is, a direction rotated 90° with respect to the first direction (Y), and is thus included in the range of directions of the maximum gas load from 80° to 110°.

[0068] As described above, the rigidity of the drive shaft (25) in the second direction (X) is higher than the rigidity in the first direction (Y). Thus, the shaft deflection of the drive shaft (25) can be reduced even if the maximum gas load during the rotational driving of the compression mechanism (50) is applied to the drive shaft (25) in the second direction (X).

[0069] To further improve the rigidity of the drive shaft (25) against the maximum gas load during the rotational driving of the compression mechanism (50), the shape of the oil passage (30) may be determined so that the direction of the maximum gas load (108°) coincides with the angle of the second direction (X).

[0070] It is preferable that the length y of the oil hole (31) in the first direction (Y) is determined so that both ends of the phantom envelope (40) in the first direction (Y) are located radially outward of the intake port (28a) of the oil supply pump (28), as viewed in the axial direction. This configuration enables smooth supply of oil through a centrifugal pump using centrifugal force generated by the rotation of the drive shaft (25).-Advantages of First Embodiment-

[0071] According to a feature of this embodiment, the rigidity of the drive shaft (25) can be increased by forming the oil passage (30) such that the length in the first direction (Y) is greater than the length in the second direction (X) in the region surrounded by the phantom envelope (40).

[0072] Thus, even when the centrifugal force is applied to the drive shaft (25) by the eccentric weights of the eccentric portion (27) and the piston (54) during rotation of the drive shaft (25), the shaft deflection of the drive shaft (25) can be reduced.

[0073] Further, by setting the distance from the center of rotation of the drive shaft (25) to the inner wall surface of the oil passage (30) at a point farthest from the center of rotation in the radial direction to be equivalent to the radius of a circular oil passage, an equivalent centrifugal pumping action can be obtained.

[0074] Reduction of the shaft deflection of such a drive shaft (25) makes it possible to reduce noise generated by whirling of the drive shaft (25).

[0075] According to a feature of this embodiment, the rigidity of the drive shaft (25) in the second direction (X) is higher than the rigidity in the first direction (Y). Thus, the shaft deflection of the drive shaft (25) can be reduced even if the maximum gas load during the rotational driving of the compression mechanism (50) is applied to the drive shaft (25) in the second direction (X).

[0076] According to a feature of this embodiment, by forming the oil passage (30) as the long oil hole (31) extending along the first direction (Y) as viewed in the axial direction, the rigidity of the drive shaft (25) in the second direction (X) can be higher than the rigidity in the first direction (Y).

[0077] According to a feature of this embodiment, the oil passage (30) having a shape in which the length in the first direction (Y) is greater than the length in the second direction (X) in the region surrounded by the phantom envelope (40) is applicable to a rotary compressor in which the compression mechanism (50) is arranged below the motor (21).

[0078] According to a feature of this embodiment, it is possible to provide a refrigeration apparatus including the rotary compressor (10) and the refrigerant circuit (1a).«Second Embodiment»

[0079] In the following description, the same reference characters designate the same components as those of the first embodiment, and the description is focused only on the difference.

[0080] As illustrated in FIG. 12, the oil hole (31) of the oil passage (30) is formed as a rectangular hole extending along the first direction (Y) as viewed in the axial direction. In the example shown in FIG. 12, a phantom envelope (40) that envelops the oil hole (31) as viewed in the axial direction is indicated by the phantom line. The phantom envelope (40) is represented as lines in the form of a rectangle extending along the inner peripheral edge of the oil hole (31).

[0081] As viewed in the axial direction, the oil passage (30) has the length y in the first direction (Y) that is greater than the length x in the second direction (X) in a region surrounded by the phantom envelope (40) that envelops the oil hole (31).-Advantages of Second Embodiment-

[0082] According to a feature of this embodiment, the rigidity of the drive shaft (25) in the second direction (X) can be higher than the rigidity in the first direction (Y).«Third Embodiment»

[0083] As illustrated in FIG. 13, the oil passage (30) is formed by a plurality of oil holes (31) arranged along the first direction (Y) as viewed in the axial direction. All the multiple oil holes (31) are formed to have the same inside diameter. In the example shown in FIG. 13, four oil holes (31) are arranged along the first direction (Y), which is merely an example and is not limited thereto. In the example shown in FIG. 13, a phantom envelope (40) that envelops the plurality of oil holes (31) as viewed in the axial direction is indicated by the phantom line. The phantom envelope (40) is represented as a curve in the form of a long hole extending along the first direction (Y).

[0084] As viewed in the axial direction, the oil passage (30) has the length y in the first direction (Y) that is greater than the length x in the second direction (X) in a region surrounded by the phantom envelope (40) that envelops the plurality of oil holes (31).

[0085] In this embodiment, the multiple oil holes (31) are arranged symmetrically with respect to the axis (C1) of the main shaft portion (26), but are not limited thereto. The oil holes (31) may be arranged asymmetrically.

[0086] It is preferable that positions of the oil holes (31) in the first direction (Y) are determined so that both ends of the phantom envelope (40) in the first direction (Y) are located radially outward of the intake port (28a) of the oil supply pump (28), as viewed in the axial direction. This configuration enables smooth supply of oil through a centrifugal pump using centrifugal force generated by the rotation of the drive shaft (25).

[0087] Two oil holes (31) located between the oil holes (31) located at both ends in the first direction (Y) are used to discharge gas contained in the oil through the vent hole (37).-Advantages of Third Embodiment-

[0088] According to a feature of this embodiment, by forming the oil passage (30) as a plurality of oil holes (31) arranged along the first direction (Y), the rigidity of the drive shaft (25) in the second direction (X) can be higher than the rigidity in the first direction (Y).«Fourth Embodiment»

[0089] As illustrated in FIG. 14, the oil passage (30) is formed by a plurality of oil holes (31) arranged along the first direction (Y) as viewed in the axial direction. The plurality of oil holes (31) includes holes having different inside diameters. In the example shown in FIG. 14, three oil holes (31) are spaced apart from one another in the first direction (Y), which is merely an example and is not limited thereto. Among the three oil holes (31), the oil hole (31) located in the middle in the first direction (Y) has a larger inside diameter than the oil holes (31) located at both ends in the first direction (Y).

[0090] In the example shown in FIG. 14, a phantom envelope (40) that envelops the plurality of oil holes (31) as viewed in the axial direction is indicated by the phantom line. The phantom envelope (40) is represented as a curve defining a shape in which the length x in the second direction (X) is greatest at the middle in the first direction (Y) and gradually decreases toward both ends in the second direction (X).

[0091] As viewed in the axial direction, the oil passage (30) has the length y in the first direction (Y) that is greater than the length x in the second direction (X) in a region surrounded by the phantom envelope (40) that envelops the plurality of oil holes (31). In this description, the length x at the middle in the second direction (X), which is the greatest length x in the second direction (X), is compared to the length y in the first direction (Y).

[0092] The oil hole (31) located between the oil holes (31) located at both ends in the first direction (Y) is used to discharge gas contained in the oil through the vent hole (37).-Advantages of Fourth Embodiment-

[0093] According to a feature of this embodiment, by forming the oil passage (30) as a plurality of oil holes (31) arranged along the first direction (Y), the rigidity of the drive shaft (25) in the second direction (X) can be higher than the rigidity in the first direction (Y).«Fifth Embodiment»

[0094] As illustrated in FIG. 15, the oil passage (30) is formed by a plurality of oil holes (31) arranged along the first direction (Y) as viewed in the axial direction. All the multiple oil holes (31) are formed to have the same inside diameter. In the oil passage (30), the oil holes (31) are arranged so that the oil holes (31) adjacent to each other partially overlap each other as viewed in the axial direction.

[0095] In the example shown in FIG. 15, a phantom envelope (40) that envelops the plurality of oil holes (31) as viewed in the axial direction is indicated by the phantom line. The phantom envelope (40) is represented as a curve in the form of a long hole extending along the first direction (Y).

[0096] As viewed in the axial direction, the oil passage (30) has the length y in the first direction (Y) that is greater than the length x in the second direction (X) in a region surrounded by the phantom envelope (40) that envelops the plurality of oil holes (31).-Advantages of Fifth Embodiment-

[0097] According to a feature of this embodiment, assuming that the length in the first direction (Y) of the region surrounded by the phantom envelope (40) is constant, the number of oil holes (31) in the region surrounded by the phantom envelope (40) is greater when adjacent oil holes (31) partially overlap with each other than when adjacent oil holes (31) are spaced apart from each other. Thus, machining the oil passage (30) into a long-hole shape becomes easier.«Sixth Embodiment»

[0098] As illustrated in FIG. 16, the rotary compressor (10) includes a casing (11), a drive mechanism (20), and a compression mechanism (50).

[0099] The drive mechanism (20) includes a motor (21) and a drive shaft (25). The drive shaft (25) has a main shaft portion (26) and two eccentric portions (27). The eccentric portions (27) each have an axis decentered by a predetermined distance with respect to the axis of the main shaft portion (26). The two eccentric portions (27) are eccentric in directions that differ from each other by 180° (see also FIG. 17).

[0100] The compression mechanism (50) includes two cylinders (51), a front head (52), a rear head (53), two pistons (54), and a middle plate (60). The middle plate (60) is sandwiched between the two cylinders (51).

[0101] As illustrated in FIG. 17, the axis of the main shaft portion (26) is referred to as the axis (C1), and the axes of the two eccentric portions (27) are referred to as the axes (C2). As viewed in the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a phantom envelope (40) that envelops the oil hole (31) is referred to as a first direction (Y), and a direction orthogonal to the first direction (Y) is referred to as a second direction (X).

[0102] In the example shown in FIG. 17, as viewed in the axial direction of the drive shaft (25), the direction that connects the axis (C1) of the main shaft portion (26) and the axis (C2) of each eccentric portion (27) is referred to as the first direction (Y), and the direction orthogonal to the first direction (Y) is referred to as the second direction (X), as non-limiting configurations.

[0103] The oil passage (30) is formed as a long oil hole (31) extending along the first direction (Y) as viewed in the axial direction. In the example shown in FIG. 17, the phantom envelope (40) that envelops the oil hole (31) as viewed in the axial direction is indicated by the phantom line. The phantom envelope (40) is represented as a curve in the form of a long hole extending along the inner peripheral edge of the oil hole (31).

[0104] As viewed in the axial direction, the oil passage (30) has the length y in the first direction (Y) that is greater than the length x in the second direction (X) in a region surrounded by the phantom envelope (40) that envelops the oil hole (31).

[0105] The oil passage (30) may be formed by a plurality of oil holes (31) arranged along the first direction (Y) as viewed in the axial direction, similarly to the third embodiment described above. Alternatively, the oil passage (30) may be formed by a plurality of oil holes (31) arranged so that the oil holes (31) adjacent to each other partially overlap each other, as viewed in the axial direction, similarly to the fifth embodiment described above.-Advantages of Sixth Embodiment-

[0106] According to a feature of this embodiment, the rigidity of the drive shaft (25) in the second direction (X) can be higher than the rigidity in the first direction (Y).«Other Embodiments»

[0107] The above-described embodiments may be modified as follows.

[0108] In this embodiment, the oil hole (31) of the oil passage (30) is formed as a long hole extending along the first direction (Y) as viewed in the axial direction, but is not limited thereto. For example, the oil hole (31) may be formed as an elliptical hole extending along the first direction (Y) as viewed in the axial direction.

[0109] In this embodiment, the oil supply pump (28) is attached to the lower end of the drive shaft (25) so that oil can be sucked up through the oil supply pump (28), but is not limited thereto. For example, the drive shaft (25) may be extended to a position where its lower end is immersed in oil in the oil reservoir (18), and the lower end hole (35) of the oil passage (30), which is open to the lower end of the drive shaft (25), may be covered with an end plate member (not shown) having a central inlet hole. Thus, oil can be sucked up through the inlet hole of the end plate member into the oil passage (30) of the drive shaft (25).

[0110] The plurality of oil holes (31) may be used according to their respective purposes. For example, one of the oil holes (31) may be used as a passage for supplying oil to the sliding portions between the drive shaft (25) and the front and rear heads (52) and (53), while another oil hole (31) may be used as a passage for supplying oil to the cylinder (51).

[0111] While the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. The elements according to the embodiments, the variations thereof, and the other embodiments may be combined and replaced with each other. In addition, the expressions of "first," "second," "third," . . . , in the specification and claims 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

[0112] As can be seen from the foregoing description, the present disclosure is useful for a rotary compressor and a refrigeration apparatus.DESCRIPTION OF REFERENCE CHARACTERS

[0113] 1Refrigeration Apparatus 1aRefrigerant Circuit 10Rotary Compressor 21Motor 25Drive Shaft 26Main Shaft Portion 27Eccentric Portion 30Oil Passage 31Oil Hole 40Phantom Envelope 50Compression Mechanism C1Axis C2Axis XSecond Direction YFirst Direction

Claims

1. A rotary compressor comprising: a compression mechanism (50); and a drive shaft (25) configured to rotationally drive the compression mechanism (50), the drive shaft (25) including a main shaft portion (26) and an eccentric portion (27), the eccentric portion (27) being eccentric with respect to an axis (C1) of the main shaft portion (26) by a predetermined distance, the drive shaft (25) having an oil passage (30) including one or more oil holes (31) extending in an axial direction, as viewed in the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a phantom envelope (40) that envelops the one or more oil holes (31) being referred to as a first direction (Y), a direction orthogonal to the first direction (Y) being referred to as a second direction (X), as viewed in the axial direction, the oil passage (30) has a length in the first direction (Y) that is greater than a length in the second direction (X) in the region surrounded by the phantom envelope (40).

2. The rotary compressor of claim 1, wherein the first direction (Y) is a direction that connects the axis (C1) of the main shaft portion (26) and an axis (C2) of the eccentric portion (27), as viewed in the axial direction of the drive shaft (25).

3. The rotary compressor of claim 1 or 2, wherein the oil passage (30) is formed as a long oil hole (31) extending along the first direction (Y) as viewed in the axial direction.

4. The rotary compressor of claim 1 or 2, wherein the oil passage (30) is formed by the plurality of oil holes (31) arranged along the first direction (Y) as viewed in the axial direction.

5. The rotary compressor of claim 4, wherein in the oil passage (30), the plurality of oil holes (31) is arranged so that the oil holes (31) adjacent to each other partially overlap each other as viewed in the axial direction.

6. The rotary compressor of any one of claims 1 to 5, further comprising: a motor (21) configured to rotate the drive shaft (25), wherein the compression mechanism (50) is disposed below the motor (21).

7. A refrigeration apparatus, comprising: the rotary compressor (10) of any one of claims 1 to 6; and a refrigerant circuit (1a) through which a refrigerant compressed by the rotary compressor (10) flows.

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