Rotary compressor and refrigeration apparatus

Abstract

A drive shaft (25) has a main shaft section (26) and an eccentric section (27). The drive shaft (25) is provided with an oil passage (30). The oil passage (30) has one or more oil holes (31) extending in the axial direction. When viewed from the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a virtual envelope (40) that envelops the oil hole (31) is defined as a first direction (Y), and a direction orthogonal to the first direction (Y) is defined as a second direction (X). When viewed from the axial direction, the length of the oil passage (30) in the first direction (Y) in the region surrounded by the virtual envelope (40) is longer than the length in the second direction (X).

Description

Rotary compressor and refrigeration device

[0001] The present disclosure relates to a rotary compressor and a refrigeration device.

[0002] Patent Document 1 discloses a compressor including a compression mechanism having a rolling piston and a drive shaft (rotating shaft) that rotates the rolling piston eccentrically. The drive shaft has an oil passage (center hole) extending in the axial direction. Refrigeration oil stored in the bottom of a sealed container is supplied to each sliding part through the oil passage.

[0003] Patent No. 7003305

[0004] Here, there is a problem in that centrifugal force and gas load are applied to the drive shaft as the compression mechanism is rotated, which increases the axial deflection of the drive shaft.

[0005] Therefore, the inventors of the present application focused on the oil passage, which is a factor in reducing the rigidity of the drive shaft, and investigated ways to improve the rigidity of the drive shaft by devising the shape of the oil passage.

[0006] An object of the present disclosure is to suppress axial deflection of the drive shaft by devising the shape of the oil passage.

[0007] A first aspect of the present disclosure is a rotary compressor including a compression mechanism (50) and a drive shaft (25) that rotationally drives the compression mechanism (50), wherein the drive shaft (25) has a main shaft portion (26) and an eccentric portion (27) that is eccentric from an axial center (C1) of the main shaft portion (26) by a predetermined amount, and the drive shaft (25) is provided with an oil passage (30) having one or more oil holes (31) extending in an axial direction, wherein, as viewed from the axial direction of the drive shaft (25), a predetermined direction in an area surrounded by a virtual envelope (40) that envelops the oil holes (31) is defined as a first direction (Y), and a direction perpendicular to the first direction (Y) is defined as a second direction (X), and the length of the oil passage (30) in the area surrounded by the virtual envelope (40) as viewed from the axial direction is longer in the first direction (Y) than in the second direction (X).

[0008] In the first aspect, by forming the oil passage (30) such that the length in the first direction (Y) in the area surrounded by the imaginary envelope (40) is longer than the length in the second direction (X), the rigidity of the drive shaft (25) can be improved and axial deflection can be reduced.

[0009] Specifically, in order to pump oil by centrifugal pumping action, the centrifugal pump must be structurally provided with a small diameter portion on the inlet side and a large diameter portion on the outlet side with a larger hole diameter than the small diameter portion.

[0010] In the case of a conventional rotary compressor, the small diameter portion on the inlet side of the centrifugal pump corresponds to the suction port that opens in a tapered shape at the bottom end of the centrifugal pump, and the large diameter portion on the outlet side corresponds to a circular oil passage that extends axially through the center of the drive shaft (25). Therefore, in the conventional rotary compressor, a circular, relatively large diameter oil passage whose diameter is the length in the first direction (Y) is provided in the center of the drive shaft (25), which may reduce the rigidity of the drive shaft (25).

[0011] In contrast, by making the length of the oil passage (30) in the second direction (X) shorter than the length of the oil passage (30) in the first direction (Y), the passage area of ​​the oil passage (30) becomes smaller than when a circular oil passage is provided in the center of the drive shaft (25), thereby improving the rigidity of the drive shaft (25) and reducing axial deflection.

[0012] In addition, by ensuring that the distance from the center of rotation of the drive shaft (25) in the oil passage (30) to the inner wall surface at the point farthest radially therefrom is equal to the radius of the circular oil passage, an equivalent centrifugal pumping action can be obtained.

[0013] In a second aspect of the present disclosure, in the rotary compressor of the first aspect, the first direction (Y) is a direction connecting the axial center (C1) of the main shaft portion (26) and the axial center (C2) of the eccentric portion (27) when viewed from the axial direction of the drive shaft (25).

[0014] In 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). Therefore, even if the maximum gas load during rotational driving of the compression mechanism (50) is applied to the drive shaft (25) in the second direction (X), axial deflection of the drive shaft (25) can be suppressed.

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

[0016] In the third aspect, the oil passage (30) is formed by an elongated oil hole (31) extending along the first direction (Y) when viewed from the axial direction, thereby making it possible to increase the rigidity of the drive shaft (25) in the second direction (X) compared to the rigidity in the first direction (Y).

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

[0018] In the fourth aspect, the oil passage (30) is formed by a plurality of oil holes (31) arranged along the first direction (Y), so that the rigidity of the drive shaft (25) in the second direction (X) can be made higher than the rigidity in the first direction (Y).

[0019] In a fifth aspect of the present disclosure, in the rotary compressor of the fourth aspect, the oil passage (30) is configured such that adjacent oil holes (31) partially overlap with each other when viewed in the axial direction.

[0020] In the fifth aspect, when the length in the first direction (Y) of the region surrounded by the imaginary envelope (40) is constant, the number of oil holes (31) in the region surrounded by the imaginary envelope (40) increases when adjacent oil holes (31) are partially overlapped compared to when adjacent oil holes (31) are spaced apart from each other, which makes it easier to process the oil passage (30) into an elongated hole shape.

[0021] A sixth aspect of the present disclosure is a rotary compressor according to any one of the first to fifth aspects, further comprising a motor (21) that rotates the drive shaft (25), and the compression mechanism (50) is disposed below the motor (21).

[0022] In the sixth aspect, for a rotary compressor in which the compression mechanism (50) is arranged below the motor (21), a shape of the oil passage (30) can be applied in which the length in the first direction (Y) in the area surrounded by the virtual envelope (40) is longer than the length in the second direction (X).

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

[0024] In the seventh aspect, a refrigeration system can be provided, which includes a rotary compressor (10) and a refrigerant circuit (1a).

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

[0026] First Embodiment As shown in Fig. 1, a rotary compressor (10) is provided in a refrigeration system (1). The refrigeration system (1) has a refrigerant circuit (1a) filled with a refrigerant. The refrigerant circuit (1a) has a rotary compressor (10), a radiator (3), a pressure reduction mechanism (4), and an evaporator (5). The pressure reduction mechanism (4) is, for example, an expansion valve. The refrigerant circuit (1a) performs a vapor compression refrigeration cycle.

[0027] The refrigeration system (1) is an air conditioning system. The air conditioning system may be a cooling-only system, a heating-only system, or an air conditioning system that switches between cooling and heating. In this case, the air conditioning system has a switching mechanism (e.g., a four-way switching valve) that switches the refrigerant circulation direction. The refrigeration system (1) may be a water heater, a chiller unit, a cooling system that cools the air inside a storage unit, or the like. The cooling system cools the air inside a refrigerator, a freezer, a container, or the like.

[0028] As shown 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 a vertically long, cylindrical, sealed container. A suction pipe (16) is fixed to and passes through the body of the casing (11). An accumulator (not shown) is connected to the suction pipe (16). A discharge pipe (17) is fixed to and passes through the upper part of the casing (11).

[0030] An oil reservoir (18) is provided at the bottom of the casing (11). Oil is stored in the oil reservoir (18). The oil is used to lubricate the sliding parts of the compression mechanism (50) and the drive shaft (25).

[0031] <Drive Mechanism> The drive mechanism (20) is housed inside the casing (11). The drive mechanism (20) has a motor (21) and a drive shaft (25). The motor (21) is disposed above the compression mechanism (50). The motor (21) has a stator (22) and a rotor (23).

[0032] The stator (22) is fixed to the inner peripheral surface of the casing (11). The rotor (23) passes through the interior of the stator (22) in the vertical direction. A drive shaft (25) is fixed to the interior of the axial center of the rotor (23). When the motor (21) is energized, the drive shaft (25) is rotated together with the rotor (23).

[0033] The drive shaft (25) is disposed on the axial center 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). An intake port (28a) is provided at the bottom of the oil supply pump (28). The oil supply pump (28) transports oil stored in the oil reservoir (18). The transported oil is supplied to the compression mechanism (50) and the sliding parts of the drive shaft (25) through the oil passage (30) of 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 axis of the eccentric portion (27) is eccentric from the axis of the main shaft portion (26) by a predetermined amount.

[0035] The main shaft portion (26) above the eccentric portion (27) is rotatably supported by a front head (52) described later, and the main shaft portion (26) below the eccentric portion (27) is rotatably supported by a rear head (53) described later.

[0036] <Compression Mechanism> The compression mechanism (50) is housed inside the casing (11). The compression mechanism (50) is disposed below the motor (21). The compression mechanism (50) has a cylinder (51), a front head (52), a rear head (53), and a piston (54).

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

[0038] The front head (52) is disposed above the cylinder (51). The front head (52) is disposed so as to cover 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). A discharge passage (not shown) is formed in the front head (52) and passes through it in the axial direction.

[0039] The rear head (53) is disposed below the cylinder (51). The rear head (53) is disposed so as to cover 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 shown in Figure 3, the piston (54) is housed inside the cylinder (51). The blade (57) is integrally formed with the piston (54). The cylinder (51) and the piston (54) define a compression chamber (55). The piston (54) is formed in a perfect circular ring shape. The eccentric portion (27) of the drive shaft (25) is fitted inside the piston (54).

[0041] The interior of the compression chamber (55) is divided 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) so as to be able to swing.

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

[0043] Next, when the low-pressure chamber (55a) is isolated from the suction passage (56), the isolated space forms the high-pressure chamber (55b). As the volume of the high-pressure chamber (55b) gradually decreases, the internal pressure of the high-pressure chamber (55b) increases. 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 the discharge passage (59). This 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). The high-pressure refrigerant that has flowed out above the motor (21) is sent to the refrigerant circuit (1a) through the discharge pipe (17).

[0044] <Oil Passage> Incidentally, as the compression mechanism (50) is rotated, centrifugal force and gas load are applied to the drive shaft (25), which causes a problem of increased axial deflection of the drive shaft (25).

[0045] Therefore, the inventors of the present application focused on the oil passage (30), which is a factor that reduces the rigidity of the drive shaft (25), and investigated ways to increase the rigidity of the drive shaft (25) by devising the shape of the oil passage (30).

[0046] As shown in Figure 2, the drive shaft (25) is provided with an oil passage (30). The oil passage (30) has an oil hole (31), a bottom end hole (35), and a horizontal hole (36).

[0047] The lower end hole (35) opens at the lower end of the main shaft portion (26) of the drive shaft (25). An 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 horizontal hole (36) communicates with the oil hole (31) and extends horizontally. The horizontal hole (36) opens at a position where oil can be supplied to the compression mechanism (50) and the sliding parts of the drive shaft (25).

[0048] In the example shown in Fig. 2, the horizontal hole (36) opens to the sliding surfaces of the front head (52), the rear head (53), and the piston (54). A gas vent hole (37) is formed in the drive shaft (25) at a position above the front head (52). The gas vent hole (37) discharges gas contained in 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 horizontal hole (36) due to the centrifugal force generated by the rotation of the drive shaft (25), and is supplied to the compression mechanism (50) and the sliding parts of the drive shaft (25).

[0050] As shown in Figure 4, the axis of the main shaft portion (26) is defined as an axis (C1), and the axis of the eccentric portion (27) is defined as an axis (C2). When viewed from the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a virtual envelope (40) enveloping the oil hole (31) is defined as a first direction (Y), and a direction perpendicular to the first direction (Y) is defined as a second direction (X).

[0051] In the example shown in Figure 4, when viewed from the axial direction of the drive shaft (25), the direction connecting the axial center (C1) of the main shaft portion (26) and the axial center (C2) of the eccentric portion (27) is defined as the first direction (Y), and the direction perpendicular to the first direction (Y) is defined as the second direction (X), but this is not limited to this embodiment.

[0052] The oil passage (30) is formed by an elongated oil hole (31) extending in a first direction (Y) when viewed from the axial direction. Here, the length of the oil hole (31) in the second direction (X) is defined as x, and the length of the oil hole (31) in the first direction (Y) is defined as y. The elongated oil hole (31) can be expressed as a locus when a circle with a diameter x is continuously moved in the first direction (Y). Here, a curve that is tangent to all the circles is referred to as an envelope. In the example shown in FIG. 4 , a virtual envelope (40) that envelops the oil hole (31) when viewed from the axial direction is shown by a virtual line. The virtual envelope (40) is expressed as a virtual curve that extends along the inner circumferential edge of the oil hole (31).

[0053] Here, when viewed in the axial direction, the length y of the oil passage (30) in the first direction (Y) in a region surrounded by a virtual envelope (40) enveloping the oil hole (31) is longer than the length x of the oil passage (30) in the second direction (X), thereby improving the rigidity of the drive shaft (25) and reducing shaft deflection.

[0054] Specifically, if a circular oil passage having a diameter equal to the length in the first direction (Y) and a larger hole diameter than the intake port (28a) is provided in the center of the drive shaft (25) in order to suck up oil by centrifugal pump action, a relatively large cavity (see the area surrounded by the virtual line in Figure 5) will be provided in the center of the drive shaft (25), which may reduce the rigidity of the drive shaft (25).

[0055] In contrast, by making the length of the oil passage (30) in the second direction (X) shorter than the length of the oil passage (30) in the first direction (Y), the passage area of ​​the oil passage (30) becomes smaller than when a circular oil passage is provided in the center of the drive shaft (25), thereby improving the rigidity of the drive shaft (25) and reducing axial deflection.

[0056] In addition, by ensuring that the distance from the center of rotation of the drive shaft (25) in the oil passage (30) to the inner wall surface at the point farthest radially from the center of rotation of the drive shaft (25) is equal to the radius of the circular oil passage, an equivalent centrifugal pumping action can be obtained (see Figure 5).

[0057] Furthermore, by forming the oil passage (30) such that the length in the first direction (Y) in the region surrounded by the virtual envelope (40) is longer than the length in the second direction (X), the rigidity of the drive shaft (25) in the second direction (X) can be made 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 Figures 6 and 7. Note that Figures 6 and 7 only show the main shaft portion (26) of the drive shaft (25), and the eccentric portion (27) is not shown. For ease of explanation, the oil hole (31) will be described as having a rectangular shape extending in the first direction (Y) that approximates the shape of an elongated hole, rather than an elongated hole.

[0059] As shown in Fig. 6, the diameter of the main shaft portion (26) is defined as D. When a 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 equation (1).

[0060] Iy = (π D ４ / 64) - (x y ３ / 12) ... (1) On the other hand, when a load is applied to the main shaft portion (26) of the drive shaft (25) in the second direction (X) as shown in FIG. 7, the second moment of area Ix is calculated by the following equation (2).

[0061] Ix = (π D ４ / 64)-(y x ３ / 12) ... (2) Here, since x<y, "y ３ The value of Iy, which includes "," decreases more than the value of Ix, which includes "y." In other words, since Ix>Iy, the bending rigidity of the drive shaft (25) in the second direction (X) becomes higher than the bending rigidity in the first direction (Y).

[0062] Next, the relationship between the rotation angle of the drive shaft (25) and the load acting on the drive shaft (25) will be described with reference to the graphs in Figures 8 to 10. As shown in Figure 3, the position in which the eccentric part (27) of the drive shaft (25) faces upward in Figure 3 is defined as the top dead center of 0°.

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

[0064] 9 is a graph showing the relationship between the angle from the top dead center and the direction of the force acting on the drive shaft (25). As shown in Fig. 9, it can be seen that at the position of 227°, which is the angle at which the maximum gas load is applied when the compression mechanism (50) is driven to rotate, the direction of the gas load acting on the drive shaft (25) is 119.18° (≈119°).

[0065] 10 is a graph showing the relationship between the angle from the top dead center and the direction of the gas load acting on the drive shaft (25) when the eccentric direction of the eccentric portion (27) is set as a reference angle of 0°. As shown in FIG. 10, at a position of 227°, which is the rotation angle at which the maximum gas load is applied when the compression mechanism (50) is driven to rotate, the direction of the gas load acting on the drive shaft (25) when the eccentric direction of the eccentric portion (27) is set as a reference angle of 0° is −107.82° (≈−108°).

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

[0067] Here, the maximum gas load direction during rotational driving of the compression mechanism (50) varies within a range of, for example, 80° to 110° depending on the compression conditions, etc. The second direction (X) is a direction perpendicular to the first direction (Y), that is, a direction rotated by 90° with respect to the first direction (Y), and therefore falls within the range of the maximum gas load direction of 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), so that even when the maximum gas load during rotational driving of the compression mechanism (50) is applied to the drive shaft (25) in the second direction (X), axial deflection of the drive shaft (25) can be suppressed.

[0069] In addition, in order to further increase the rigidity of the drive shaft (25) against the maximum gas load when the compression mechanism (50) is driven to rotate, the shape of the oil passage (30) may be set so that the angle of the maximum gas load direction (108°) and the angle of the second direction (X) coincide with each other.

[0070] In addition, it is preferable to set the length y of the oil hole (31) in the first direction (Y) so that both ends of the imaginary 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. In this way, oil can be smoothly supplied by the centrifugal pump using centrifugal force generated by the rotation of the drive shaft (25).

[0071] -Effects of Embodiment 1- According to the features of this embodiment, the rigidity of the drive shaft (25) can be improved by forming the oil passage (30) such that the length in the first direction (Y) in the area surrounded by the imaginary envelope (40) is longer than the length in the second direction (X).

[0072] As a result, when the drive shaft (25) rotates, the eccentric weight of the eccentric portion (27) and the piston (54) reduces axial deflection of the drive shaft (25) even when centrifugal force is applied to the drive shaft (25).

[0073] In addition, by ensuring that the distance from the center of rotation of the drive shaft (25) in the oil passage (30) to the inner wall surface at the point farthest radially therefrom is equal to the radius of the circular oil passage, an equivalent centrifugal pumping action can be obtained.

[0074] By reducing such axial deflection of the drive shaft (25), it is possible to reduce noise caused by whirling of the drive shaft (25).

[0075] According to the features 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). Therefore, even if the maximum gas load during rotational driving of the compression mechanism (50) is applied to the drive shaft (25) in the second direction (X), axial deflection of the drive shaft (25) can be suppressed.

[0076] According to the feature of this embodiment, the oil passage (30) is formed by an elongated oil hole (31) extending along the first direction (Y) when viewed from the axial direction, thereby making it possible to make the rigidity of the drive shaft (25) in the second direction (X) higher than the rigidity in the first direction (Y).

[0077] According to the features of this embodiment, a shape of the oil passage (30) in which the length in the first direction (Y) in the area surrounded by the virtual envelope (40) is longer than the length in the second direction (X) can be applied to a rotary compressor in which the compression mechanism (50) is arranged below the motor (21).

[0078] According to the features of the present embodiment, a refrigeration system including a rotary compressor (10) and a refrigerant circuit (1a) can be provided.

[0079] Second Embodiment Hereinafter, the same parts as those in the first embodiment will be denoted by the same reference numerals, and only the differences will be described.

[0080] As shown in Fig. 12 , the oil hole (31) of the oil passage (30) is formed as a rectangular hole extending in the first direction (Y) when viewed in the axial direction. In the example shown in Fig. 12 , a virtual envelope (40) that encloses the oil hole (31) when viewed in the axial direction is shown by a virtual line. The virtual envelope (40) is represented as a rectangular line extending along the inner circumferential edge of the oil hole (31).

[0081] Here, when viewed from the axial direction, the length y of the oil passage (30) in the first direction (Y) in the area surrounded by the imaginary envelope (40) enveloping the oil hole (31) is longer than the length x of the oil passage (30) in the second direction (X).

[0082] Effect of Second Embodiment According to the features of this embodiment, the rigidity of the drive shaft (25) in the second direction (X) can be made higher than the rigidity in the first direction (Y).

[0083] Third Embodiment As shown in FIG. 13 , the oil passage (30) is formed by a plurality of oil holes (31) aligned along the first direction (Y) as viewed in the axial direction. The plurality of oil holes (31) are all formed as holes with the same inner diameter. In the example shown in FIG. 13 , four oil holes (31) are provided along the first direction (Y), but this is merely an example and the present invention is not limited to this. In the example shown in FIG. 13 , a virtual envelope (40) that encloses the plurality of oil holes (31) as viewed in the axial direction is shown by a virtual line. The virtual envelope (40) is represented as an elongated curve extending along the first direction (Y).

[0084] Here, when viewed from the axial direction, the length y of the oil passage (30) in the first direction (Y) in the area surrounded by the imaginary envelope (40) enveloping the plurality of oil holes (31) is longer than the length x of the oil passage (30) in the second direction (X).

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

[0086] In addition, it is preferable to set the position of the oil hole (31) in the first direction (Y) so that both ends of the imaginary 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. In this way, oil can be smoothly supplied by the centrifugal pump using centrifugal force generated by the rotation of the drive shaft (25).

[0087] The two oil holes (31) arranged between the oil holes (31) at both ends in the first direction (Y) are used to discharge gas contained in the oil through the gas vent hole (37).

[0088] -Effects of Embodiment 3- According to the features of this embodiment, the oil passage (30) is formed by a plurality of oil holes (31) aligned along the first direction (Y), so that the rigidity of the drive shaft (25) in the second direction (X) can be made higher than the rigidity in the first direction (Y).

[0089] Fourth Embodiment As shown in Fig. 14 , the oil passage (30) is formed with a plurality of oil holes (31) aligned along the first direction (Y) as viewed in the axial direction. The plurality of oil holes (31) includes holes with different inner diameters. In the example shown in Fig. 14 , three oil holes (31) are provided spaced apart in the first direction (Y), but this is merely an example and is not limiting. Of the three oil holes (31), the oil hole (31) located in the center in the first direction (Y) has a larger inner diameter than the oil holes (31) located at both ends in the first direction (Y).

[0090] In the example shown in Fig. 14, a virtual envelope (40) that encloses the plurality of oil holes (31) as viewed in the axial direction is shown by a virtual line. The virtual envelope (40) is expressed as a curve whose length x in the second direction (X) is greatest at the center in the first direction (Y) and gradually decreases toward both ends in the second direction (X).

[0091] Here, when viewed from the axial direction, the length y of the oil passage (30) in the first direction (Y) in a region surrounded by a virtual envelope (40) that encloses the plurality of oil holes (31) is longer than the length x of the oil passage (30) in the second direction (X). Here, the length x of the central portion in the second direction (X), which is the position where the length x in the second direction (X) is greatest, is compared with the length y in the first direction (Y).

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

[0093] -Effects of Embodiment 4- According to the features of this embodiment, by forming the oil passage (30) with a plurality of oil holes (31) aligned along the first direction (Y), 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).

[0094] Fifth Embodiment As shown in Fig. 15 , the oil passage (30) is formed of a plurality of oil holes (31) aligned along the first direction (Y) as viewed in the axial direction. The plurality of oil holes (31) are all formed as holes having the same inner diameter. In the oil passage (30), adjacent oil holes (31) partially overlap as viewed in the axial direction.

[0095] 15, a virtual envelope (40) that encloses the plurality of oil holes (31) as viewed in the axial direction is shown by a virtual line. The virtual envelope (40) is represented as a curved elongated hole extending along the first direction (Y).

[0096] Here, when viewed from the axial direction, the length y of the oil passage (30) in the first direction (Y) in the area surrounded by the imaginary envelope (40) enveloping the plurality of oil holes (31) is longer than the length x of the oil passage (30) in the second direction (X).

[0097] Advantages of the Fifth Embodiment According to the features of the present embodiment, when the length in the first direction (Y) of the region surrounded by the imaginary envelope (40) is constant, the number of oil holes (31) in the region surrounded by the imaginary envelope (40) increases when adjacent oil holes (31) are partially overlapped compared to when adjacent oil holes (31) are spaced apart from each other. This makes it easier to process the oil passage (30) into an elongated hole shape.

[0098] Sixth Embodiment As shown in FIG. 16, a 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) includes a main shaft portion (26) and two eccentric portions (27). The axis of the eccentric portion (27) is eccentric from the axis of the main shaft portion (26) by a predetermined amount. The two eccentric portions (27) are eccentric in directions that are 180° apart from each other (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] 17 , the axis of the main shaft portion (26) is defined as an axis center (C1), and the axis of each of the two eccentric portions (27) is defined as an axis center (C2). When viewed from the axial direction of the drive shaft (25), a predetermined direction in a region surrounded by a virtual envelope (40) enveloping the oil hole (31) is defined as a first direction (Y), and a direction perpendicular to the first direction (Y) is defined as a second direction (X).

[0102] In the example shown in Figure 17, when viewed from the axial direction of the drive shaft (25), the direction connecting the axial center (C1) of the main shaft portion (26) and the axial center (C2) of the eccentric portion (27) is defined as the first direction (Y), and the direction perpendicular to the first direction (Y) is defined as the second direction (X), but this is not limited to this embodiment.

[0103] The oil passage (30) is formed by an elongated oil hole (31) extending in the first direction (Y) as viewed in the axial direction. In the example shown in Fig. 17, a virtual envelope (40) enclosing the oil hole (31) as viewed in the axial direction is shown by a virtual line. The virtual envelope (40) is represented as a curved elongated hole extending along the inner circumferential edge of the oil hole (31).

[0104] Here, when viewed from the axial direction, the length y of the oil passage (30) in the first direction (Y) in the area surrounded by the imaginary envelope (40) enveloping the oil hole (31) is longer than the length x of the oil passage (30) in the second direction (X).

[0105] The oil passage (30) may be configured to be formed of a plurality of oil holes (31) aligned along the first direction (Y) as viewed from the axial direction, similar to the case of the above-described embodiment 3. The oil passage (30) may be configured such that adjacent oil holes (31) partially overlap as viewed from the axial direction, similar to the case of the above-described embodiment 5.

[0106] Effect of Sixth Embodiment According to the features of this embodiment, the rigidity of the drive shaft (25) in the second direction (X) can be made higher than the rigidity in the first direction (Y).

[0107] Other Embodiments The above-described embodiment may be configured as follows.

[0108] In this embodiment, the oil hole (31) of the oil passage (30) is formed as an elongated hole extending in the first direction (Y) when viewed from the axial direction, but this is not limiting. For example, the oil hole (31) may be formed as an elliptical hole extending in the first direction (Y) when viewed from the axial direction.

[0109] In this embodiment, an oil supply pump (28) is attached to the lower end of the drive shaft (25) and oil is sucked up from the oil supply pump (28), but the present invention is not limited to this configuration. For example, the lower end of the drive shaft (25) may be extended to a position where it is immersed in the oil reservoir (18), and the lower end hole (35) of the oil passage (30) opening at the lower end of the drive shaft (25) may be covered with an end plate (not shown) having an inlet hole in its center. This allows oil to be sucked up from the inlet hole of the end plate toward the oil passage (30) of the drive shaft (25).

[0110] In addition, one of the multiple oil holes (31) may be used as an oil supply path to the sliding parts between the drive shaft (25) and the front head (52) and the rear head (53), while the other oil holes (31) may be used as an oil supply path to the cylinder (51), and the like, so that they may be used according to the application.

[0111] Although the embodiments have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above-described embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Furthermore, the terms "first," "second," "third," etc. in the specification and claims are used to distinguish between terms to which these terms are attached, and do not limit the number or order of those terms.

[0112] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for rotary compressors and refrigeration devices.

[0113] REFRIGERATION SYSTEM 1a REFRIGERATOR CIRCUIT 10 ROTARY COMPRESSOR 21 MOTOR 25 DRIVE SHAFT 26 MAIN SHAFT 27 ECCENTRIC PORTION 30 OIL PASSAGE 31 OIL HOLE 40 VIRTUAL ENVELOPE 50 COMPRESSION MECHANISM C1 AXIAL CENTER C2 AXIAL CENTER X SECOND DIRECTION Y FIRST DIRECTION

Claims

1. A rotary compressor including a compression mechanism (50) and a drive shaft (25) that rotationally drives the compression mechanism (50), wherein the drive shaft (25) has a main shaft portion (26) and an eccentric portion (27) that is eccentric by a predetermined amount from an axis (C1) of the main shaft portion (26), wherein the drive shaft (25) is provided with an oil passage (30) having one or more oil holes (31) extending in the axial direction, wherein, as viewed in the axial direction of the drive shaft (25), a predetermined direction in an area surrounded by a virtual envelope (40) that envelops the oil holes (31) is defined as a first direction (Y) and a direction perpendicular to the first direction (Y) is defined as a second direction (X), and wherein, as viewed in the axial direction, the length of the oil passage (30) in the first direction (Y) in the area surrounded by the virtual envelope (40) is longer than the length of the oil passage (30) in the second direction (X).

2. A rotary compressor according to claim 1, wherein the first direction (Y) is a direction connecting an axial center (C1) of the main shaft portion (26) and an axial center (C2) of the eccentric portion (27) when viewed in the axial direction of the drive shaft (25).

3. The rotary compressor according to claim 1 or 2, wherein the oil passage (30) is formed of an elongated oil hole (31) extending along the first direction (Y) when viewed in the axial direction.

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

5. The rotary compressor according to claim 4, wherein the oil passages (30) are arranged such that adjacent oil holes (31) partially overlap each other when viewed in the axial direction.

6. The rotary compressor according to any one of claims 1 to 5, further comprising a motor (21) that rotates the drive shaft (25), and the compression mechanism (50) is disposed below the motor (21).

7. A refrigeration system comprising: a rotary compressor (10) according to 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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