Rotary compressor and refrigeration circuit device

Abstract

The displacement volume of a compression mechanism (40) is defined as Vc [cc], the density of a refrigerant at 1.9 Mpa and 75°C as Dg [g / cm3], the number of revolutions of a rotary shaft (30) as N [rps], the volume of a primary space (S1) as V1 [cc], the volume of a secondary space (S2) as V2 [cc], the height of the primary space (S1) as H1 [cm], the height of the secondary space (S2) as H2 [cm], the density of refrigerating machine oil at 15°C as Do [g / cm3], and the solution viscosity of the refrigerating machine oil present at a level of a suction port (71a) or lower as η [mPa·S]. The rotary compressor satisfies relational expressions: N ≥ 100 [rps]; and ((8.19 × 10-8 × Vc × Dg + 0.000327) × Vc3.657 × N3.126) / (V1 × V2 × H11.867 × H21.556 × Do × η) ≤ 1.0.

Description

TECHNICAL FIELD

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

[0002] Patent Document 1 discloses a refrigeration cycle apparatus. The refrigeration cycle apparatus includes a refrigerant circuit. The refrigerant circuit includes a rotary compressor, a radiator, an expansion valve, and an evaporator. Once the rotary compressor operates, the refrigerant in the refrigerant circuit circulates to perform a refrigeration cycle.

[0003] In the rotary compressor, the refrigerant compressed by the compression mechanism flows out of the discharge pipe through the space inside the casing to the refrigerant circuit. In this manner, the inside of the casing is filled with the high-pressure refrigerant.

[0004] An oil reservoir that stores the refrigerating machine oil is formed at the bottom of the casing. The refrigerating machine oil is used to lubricate sliding portions in the rotary compressor. The refrigerating machine oil in the oil reservoir is sucked through a suction port of the oil supply pump, and is supplied through an oil supply passage in the rotary shaft to sliding portions in the compression mechanism.CITATION LISTPATENT DOCUMENT

[0005] Patent Document 1: Japanese Unexamined Patent Publication No. 2023-162986SUMMARY OF THE INVENTIONTECHNICAL PROBLEMS

[0006] As a refrigerant used in a refrigerant circuit of a refrigeration cycle apparatus, there is a hydrocarbon refrigerant, such as propane. A hydrocarbon refrigerant is a natural refrigerant and has a significantly low global warming potential. On the other hand, a hydrocarbon refrigerant generally has a molecular structure similar to that of the refrigerating machine oil and thus has characteristics of being easily dissolvable in the refrigerating machine oil. Once the refrigerant dissolves in the refrigerating machine oil, the solution viscosity of the refrigerating machine oil decreases and the viscous resistance of the refrigerating machine oil decreases. As a result, the refrigerating machine oil in the casing is likely to flow out of the discharge pipe to the refrigerant circuit together with the refrigerant, and an oil carryover rate (i.e., a ratio of the refrigerating machine oil contained in the fluid flowing out of the discharge pipe) may increase.

[0007] It is an object of the present disclosure to reduce the oil carryover rate.SOLUTION TO THE PROBLEMS

[0008] A first aspect is directed to a rotary compressor. The rotary compressor includes: an electric motor (25); a rotary shaft (30) connected to the electric motor (25); a compression mechanism (40) disposed below the electric motor (25) and configured to be driven by the rotary shaft (30) and compress a refrigerant; a casing (21) configured to house the electric motor (25), the rotary shaft (30), and the compression mechanism (40) and filled with a high-pressure refrigerant discharged from the compression mechanism (40); and an oil supply mechanism (70) having a suction port (71a) for sucking the refrigerating machine oil accumulated at a bottom of the casing (21) and configured to supply the refrigerating machine oil to a sliding portion. The compression mechanism (40) includes an annular cylinder (51A, 51B), an annular roller (52A, 52B) configured to eccentrically rotate in the cylinder (51A, 51B), and a vane (53A, 53B) for defining a compression chamber in the cylinder (51A, 51B). The internal space (S) of the casing (21) includes a primary space (S1) between the compression mechanism (40) and the electric motor (25), and a secondary space (S2) above the electric motor (25). A discharge pipe (24) communicating with the secondary space (S2) is connected to the casing (21). A refrigerant is a single component refrigerant composed of a hydrocarbon refrigerant, or a refrigerant mixture containing the hydrocarbon refrigerant. A displacement volume of the compression mechanism (40) is defined as Vc [cc], a density of the refrigerant at 1.9 Mpa and 75°C as Dg [g / cm 3< ], a number of revolutions of the rotary shaft (30) as N [rps], a volume of the primary space (S1) as V1 [cc], a volume of the secondary space (S2) as V2 [cc], a height of the primary space (S1) as H1 [cm], a height of the secondary space (S2) as H2 [cm], a density of the refrigerating machine oil at 15°C as Do [g / cm 3< ], and a solution viscosity of the refrigerating machine oil present at a level of the suction port (71a) or lower as η [mPa·S]. The rotary compressor satisfies relational expressions: N ≥ 100 [rps]; and ((8.19 × 10 -8< × Vc × Dg + 0.000327) × Vc 3.657< × N 3.126< ) / (V1 × V2 × H1 1.867< × H2 1.556< × Do × η) ≤ 1.0.

[0009] As a result of the verification, it was confirmed that the oil carryover rate α could be 1.0% or less by satisfying the relational expressions described above, even in an operation with the number N of revolutions of 100 [rps] or more. In the first aspect, the oil carryover rate α can thus be set to 1.0% or less in an operation with the number N of revolutions of the rotary shaft (30) of 100 or more.

[0010] A second aspect is an embodiment of the first aspect. In the second aspect, when an overall height of the casing (21) is defined as Hc [cm], H2 / He ≤ 0.25.

[0011] In the second aspect, by setting the height ratio to H2 / Hc ≤ 0.25, the secondary space (S2) has a relatively small volume, and the amount of the refrigerant held in the secondary space (S2) can be reduced. Accordingly, the amount of the refrigerant for use in the refrigeration cycle of the refrigerant circuit (10) can be secured.

[0012] A third aspect is an embodiment of the first or second aspect. In the third aspect, when an overall height of the casing (21) is defined as H [cm], 0.2 ≤ H2 / Hc.

[0013] In the third aspect, it is possible to substantially prevent the height H2 of the secondary space (S2) from becoming excessively small. As a result, the oil can be separated from the refrigerant in the secondary space (S2), and the oil carryover rate can thus be reduced.

[0014] A fourth aspect is an embodiment of any one of the first to third aspects. In the fourth aspect, the refrigerating machine oil includes polyalkylene glycol, polyvinyl ether, or polyol ester.

[0015] In the fourth aspect, the refrigerating machine oil includes the polyalkylene glycol, the polyvinyl ether, or the polyol ester. In these refrigerating machine oils, the hydrocarbon refrigerant is relatively less soluble. This can reduce an increase in the oil carryover rate due to the dissolution of the hydrocarbon refrigerant in the refrigerating machine oil.

[0016] A fifth aspect is an embodiment of any one of the first to fourth aspects. In the fifth aspect, a density Do [g / cm 3< ] of the refrigerant is 37 [g / cm 3< ] or more and 44 [g / cm 3< ] or less.

[0017] In the fifth aspect, the refrigerant has a relatively small density Do, and the amount of refrigerant circulating in the refrigeration cycle thus becomes small. As a result, the oil carryover rate can be reduced.

[0018] A sixth aspect is an embodiment of any one of the first to fifth aspects. In the sixth aspect, the refrigerating machine oil contains at least one of an extreme pressure additive of a phosphoric acid ester, an antioxidant, or an acid scavenger.

[0019] A seventh aspect is an embodiment of any one of the first to sixth aspects. In the seventh aspect, the refrigerating machine oil contains the antioxidant or the acid scavenger in an amount of 0.1 wt% or more and 0.5 wt% or less.

[0020] In the seventh aspect, the content of the antioxidant or the acid scavenger is set to 0.5 wt% or less with respect to the weight of the refrigerating machine oil. This can reduce an excessive decrease in the solution viscosity of the refrigerating machine oil due to an increase in the content of the antioxidant or the acid scavenger. As a result, the oil carryover rate can be reduced.

[0021] An eighth aspect is an embodiment of any one of the first to seventh aspects. In the eighth aspect, the refrigerating machine oil contains the extreme pressure additive in an amount of 1.0 wt% or more and 5.0 wt% or less.

[0022] In the eighth aspect, the content of the extreme pressure additive is set to 5.0 wt% or less with respect to the weight of the refrigerating machine oil. This can reduce an excessive decrease in the solution viscosity of the refrigerating machine oil due to an increase in the content of the extreme pressure additive. As a result, the oil carryover rate can be reduced.

[0023] A ninth aspect is an embodiment of any one of the first to eighth aspects. In the ninth aspect, the refrigerating machine oil has a molecular weight of 1000 or more and 1800 or less.

[0024] In the ninth aspect, the molecular weight of the refrigerating machine oil is set to 1000 or more and 1800 or less. This can reduce the dissolution of the hydrocarbon refrigerant in the refrigerating machine oil. As a result, the oil carryover rate can be reduced.

[0025] A tenth aspect is directed to a refrigeration cycle apparatus. The refrigeration cycle apparatus includes a refrigerant circuit (10) including the compressor (20) of any one of first to ninth aspects, and configured to circulate the hydrocarbon refrigerant to perform a refrigeration cycle.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] [FIG. 1] FIG. 1 is a piping system diagram of a refrigeration cycle apparatus. [FIG. 2] FIG. 2 is a vertical sectional view of a compressor. [FIG. 3] FIG. 3 is an enlarged vertical sectional view of a main part of the compressor. [FIG. 4] FIG. 4 is a horizontal sectional view of a first compression element. [FIG. 5] FIG. 5 is a horizontal sectional view of a second compression element. [FIG. 6] FIG. 6 is a partially-enlarged longitudinal sectional view of the compressor for illustrating a primary space and a secondary space. DESCRIPTION OF EMBODIMENTS

[0027] 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 ease of understanding.(1) Overall Configuration of Refrigeration Cycle Apparatus

[0028] A refrigeration cycle apparatus of the present disclosure is applied to a stationary air conditioner (1). As shown in FIG. 1, the air conditioner (1) is of a pair type having one outdoor unit (OU) installed outdoors and one indoor unit (IU) installed indoors. The outdoor unit (OU) and the indoor unit (IU) are connected to each other via two connection pipes.

[0029] The air conditioner (1) further includes a refrigerant circuit (10). The refrigerant circuit (10) is filled with a refrigerant. The refrigerant circulates in the refrigerant circuit (10) to perform a refrigeration cycle. The refrigerant circuit (10) includes a compressor (20), an outdoor heat exchanger (11), an expansion valve (12), and an indoor heat exchanger (13). The refrigerant circuit (10) further includes a four-way switching valve (14) for switching between a cooling cycle and a heating cycle. The compressor (20), the outdoor heat exchanger (11), and the expansion valve (12) are provided in the outdoor unit (OU), and the indoor heat exchanger (13) is provided in the indoor unit (IU). The expansion valve (12) may be provided in the indoor unit (IU).

[0030] The compressor (20) sucks and compresses a low-pressure refrigerant in the refrigerant circuit (10). The compressor (20) discharges the compressed refrigerant as a high-pressure refrigerant to the refrigerant circuit (10). The outdoor heat exchanger (11) is a fin-and-tube heat exchanger. The outdoor heat exchanger exchanges heat between the refrigerant of the refrigerant circuit (10) and the outdoor air transported by an outdoor fan (15). The expansion valve (12) is an example of the decompression mechanism that decompresses the refrigerant. The expansion valve (12) is an electronic expansion valve whose opening degree is adjustable. The indoor heat exchanger (13) is a fin-and-tube heat exchanger. The indoor heat exchanger exchanges heat between the refrigerant of the refrigerant circuit (10) and the outdoor air transported by an indoor fan (16).

[0031] The four-way switching valve (14) has a first port (P1), a second port (P2), a third port (P3), and a fourth port (P4). The four-way switching valve (14) switches between a first state indicated by solid curves in FIG. 1 and a second state indicated by broken curves in FIG. 1. The four-way switching valve (14) in the first state makes the first port (P1) and the second port (P2) communicate with each other, and the third port (P3) and the fourth port (P4) communicate with each other at the same time. When the four-way switching valve (14) is in the first state, the compressor (20) operates to perform a cooling cycle in which the outdoor heat exchanger (11) functions as a radiator (or a condenser) and the indoor heat exchanger (13) functions as an evaporator. The four-way switching valve (14) in the second state makes the first port (P1) and the third port (P3) communicate with each other, and the second port (P2) and the fourth port (P4) communicate with each other at the same time. When the four-way switching valve (14) is in the second state, the compressor (20) operates to perform a heating cycle in which the indoor heat exchanger (13) functions as a radiator (or a condenser) and the outdoor heat exchanger (11) functions as an evaporator.(2) Compressor

[0032] A configuration of the compressor (20) will be described with reference to FIGS. 2 to 6. In the following description, the terms for directions such as "upper" and "lower" refer to the directions of the arrows in FIG. 2. In the following description, an "axial direction" means a direction in which an axis (A) of a rotary shaft (30) shown in FIG. 2 extends, a "radial direction" means a direction passing through the axis (A) of the rotary shaft (30) and orthogonal to the axis (A), and a "circumferential direction" means a rotation direction of the rotary shaft (30).

[0033] The compressor (20) is a rotary compressor. The rotary compressor according to this embodiment is of a so-called swing type in which vanes (53A, 53B) formed integrally with rollers (52A, 52B) swing in accordance with eccentric rotation of the rollers (52A, 52B).

[0034] The compressor (20) includes a casing (21) and a plurality of components housed in the casing (21). The plurality of components include an electric motor (25), the rotary shaft (30), a rotary compression mechanism (40), and an oil supply mechanism (70). The electric motor (25) is a drive source of the compression mechanism (40). The rotary shaft (30) is connected to the electric motor (25). The bearings (44, 45) rotatably support the rotary shaft (30). The compression mechanism (40) is driven to rotate by the rotary shaft (30), thereby compressing the refrigerant. The oil supply mechanism (70) supplies refrigerating machine oil, which is a lubricant, to a plurality of sliding portions.(2-1) Casing

[0035] The casing (21) is a hollow closed container. The casing (21) has therein an internal space (S). The casing (21) is formed vertically long and extends in the axial direction, strictly, in the vertical direction. The casing (21) includes a cylindrical barrel (21a) extending in the vertical direction, an upper lid (21b) closing the upper end of the barrel (21a), and a lower lid (21c) closing the lower end of the barrel (21a). The lower lid (21c) constitutes the bottom of the casing (21).

[0036] The internal space (S) of the casing (21) is filled with a discharge refrigerant discharged from the compression mechanism (40). That is, the compressor (20) is of a so-called high-pressure dome type. The internal space (S) of the casing (21) includes a primary space (S1) between the compression mechanism (40) and the electric motor (25), and a secondary space (S2) above the electric motor (25).

[0037] An oil reservoir (35) that stores the refrigerating machine oil is formed at the bottom of the casing (21). In the oil reservoir (35), the oil level of the refrigerating machine oil changes in accordance with the operating conditions of the compressor (20) and the air conditioner (1).(2-2) First Suction Pipe, Second Suction Pipe, and Discharge Pipe

[0038] A first suction pipe (23A), a second suction pipe (23B), and a discharge pipe (24) are connected to the casing (21). The first suction pipe (23A) and the second suction pipe (23B) penetrate the barrel (21a) in the radial direction. The first suction pipe (23A) and the second suction pipe (23B) are connected to a low-pressure line of the refrigerant circuit (10). The discharge pipe (24) penetrates the upper lid (21b) in the axial direction. The discharge pipe (24) is connected to a high-pressure line of the refrigerant circuit (10).(2-3) Electric Motor

[0039] The electric motor (25) is located in an upper portion of the internal space (S). The electric motor (25) has a stator (26) and a rotor (27). The stator (26) is fixed to the inner circumferential surface of the barrel (21a). The stator (26) is formed in a cylindrical shape as viewed in a cross section (i.e., the horizontal cross section) perpendicular to the axial direction. The rotor (27) is disposed radially inside the stator (26). The rotor (27) is fixed to the outer circumferential surface of the rotary shaft (30). The electric motor (25) is configured such that its number of revolutions can be adjusted by an inverter device. In other words, the electric motor (25) is an inverter electric motor with a variable operation frequency.(2-4) Rotary Shaft

[0040] The rotary shaft (30) is located at the center of the internal space (S) in the radial direction. The rotary shaft (30) extends in the vertical direction. The rotary shaft (30) includes a shaft body (31), and a first eccentric portion (32A) and a second eccentric portion (32B) that are eccentric from the axis (A) of the shaft body (31) in the radial direction. The rotor (27) of the electric motor (25) is connected to an upper portion of the shaft body (31). The first eccentric portion (32A) and the second eccentric portion (32B) are formed in a lower portion of the shaft body (31). The first eccentric portion (32A) is located above the second eccentric portion (32B). The direction in which the first eccentric portion (32A) is eccentric from the axis (A) and the direction in which the second eccentric portion (32B) is eccentric from the axis are different by 180° in the circumferential direction.(2-5) General Configuration of Compression Mechanism

[0041] The compression mechanism (40) is disposed below the electric motor (25). The compression mechanism (40) includes a front head (41), a first cylinder (51A), a middle plate (42), a second cylinder (51B), and a rear head (43) in this order from top to bottom. These members are fixed to each other by bolts extending in the axial direction.

[0042] The compression mechanism (40) according to this embodiment includes a first compression element (C1) and a second compression element (C2). The first compression element (C1) includes a first roller (52A) and a first vane (53A). The second compression element (C2) includes a second roller (52B) and a second vane (53B). In the compression mechanism (40) according to this embodiment, the rollers (52A, 52B) and the vanes (53A, 53B) are integrally formed, and the vanes (53A, 53B) swing in accordance with eccentric rotation of the rollers (52A, 52B).

[0043] The first cylinder (51A) has therein a first cylinder chamber (54A). The first cylinder chamber (54A) penetrates the first cylinder (51A) in the axial direction. The second cylinder (51B) has therein a second cylinder chamber (54B). The second cylinder chamber (54B) penetrates the second cylinder (51B) in the axial direction.(2-5-1) Closing Member

[0044] The front head (41), the middle plate (42), and the rear head (43) are examples of the closing member that closes the cylinder chambers (54A, 54B) in the axial direction. The front head (41) includes a first closing portion (41a) in the shape of a flat plate slightly thick in the axial direction, and an upper bearing portion (41b) extending upward from the center of the first closing portion (41a) in the radial direction.

[0045] The lower surface of the first closing portion (41a) closes the upper opening surface of the first cylinder chamber (54A). As shown in FIG. 4, the first closing portion (41a) is provided with a first discharge port (55A) communicating with the high-pressure chamber (i.e., the compression chamber) of the first cylinder chamber (54A). The first discharge port (55A) is opened and closed by a first discharge valve (not shown).

[0046] The upper bearing portion (41b) is formed in a tubular shape extending along the rotary shaft (30) in the axial direction. The rotary shaft (30) penetrates through the inside of the upper bearing portion (41b). A first bearing (44) is formed on the inner circumferential surface of the upper bearing portion (41b). The first bearing (44) rotatably supports the main shaft portion of the rotary shaft (30). The first bearing (44) is a sliding bearing, more specifically, a journal bearing.

[0047] The middle plate (42) is disposed between the first cylinder (51A) and the second cylinder (51B). The middle plate (42) is formed in an annular shape. The rotary shaft (30) penetrates through the inside of the middle plate (42). The upper surface of the middle plate (42) closes the lower opening surface of the first cylinder chamber (54A). The lower surface of the middle plate (42) closes the upper opening surface of the second cylinder chamber (54B).

[0048] The rear head (43) includes a second closing portion (43a) in the shape of a flat plate slightly thick in the axial direction, and a lower bearing portion (43b) extending downward from the center of the second closing portion (43a) in the radial direction. The upper surface of the second closing portion (43a) closes the lower opening surface of the second cylinder chamber (54B). As shown in FIG. 5, the second closing portion (43a) is provided with a second discharge port (55B) communicating with the high-pressure chamber (i.e., the compression chamber) of the second cylinder chamber (54B). The second discharge port (55B) is opened and closed by a second discharge valve (not shown).

[0049] The lower bearing portion (43b) is formed in a tubular shape extending along the rotary shaft (30) in the axial direction. The rotary shaft (30) penetrates the inside of the lower bearing portion (43b). A second bearing (45) is formed on an inner circumferential surface of the lower bearing portion (43b). The second bearing (45) rotatably supports the auxiliary shaft portion of the rotary shaft (30). The second bearing (45) is a sliding bearing, strictly, a journal bearing.(2-5-2) Details of First Compression Element

[0050] The first compression element (C1) shown in FIG. 4 includes the first eccentric portion (32A), the first cylinder (51A), the first roller (52A), the first vane (53A), and a pair of first bushes (56A).

[0051] The first cylinder (51A) is an annular member slightly thick in the axial direction. The first cylinder (51A) has therein a first cylinder chamber (54A). The first cylinder chamber (54A) is formed in a circular shape as viewed in the axial direction. The first cylinder (51A) is provided with a first suction passage (57A) and a first bush groove (58A). The first suction passage (57A) penetrates the first cylinder (51A) in the radial direction. The first suction passage (57A) communicates with the first suction pipe (23A).

[0052] The first roller (52A) is disposed in the first cylinder chamber (54A). The first roller (52A) is formed in an annular shape as viewed in the axial direction. The first eccentric portion (32A) is fitted inside the first roller (52A). The inner circumferential surface of the first roller (52A) and the outer circumferential surface of the first eccentric portion (32A) slide relative to each other. The first eccentric portion (32A) eccentrically rotates the first roller (52A). The first roller (52A) eccentrically rotates along the inner circumferential surface of the first cylinder chamber (54A), while forming a seal portion between the first roller (52A) and the inner circumferential surface of the first cylinder chamber (54A).

[0053] The first bush groove (58A) is formed on the top dead center side (i.e., an upper side in FIG. 3) in the first cylinder (51A). The first bush groove (58A) is formed in a circular shape as viewed in the axial direction. The pair of first bushes (56A) are fitted into the first bush groove (58A). Each of the pair of first bushes (56A) has an arc portion in a shape along the inner surface of the first bush groove (58A), and a flat portion being continuous with both ends of the arc portion. The pair of first bushes (56A) are disposed in the first bush groove (58A) with the flat portions thereof facing each other. The flat portions of the pair of first bushes (56A) hold the first vane (53A). The pair of first bushes (56A) are swingable along an inner surface of the first bush groove (58A). The first vane (53A) is reciprocally movable in the radial direction between the pair of first bushes (56A).

[0054] The first vane (53A) constitutes a partitioning member partitioning the first cylinder chamber (54A) into a low-pressure chamber (L) and a high-pressure chamber (H). A radially inner portion of the first vane (53A) is continuous with the outer circumferential surface of the first roller (52A). The low-pressure chamber (L) of the first cylinder chamber (54A) communicates with the first suction passage (57A) and constitutes a suction chamber into which the low-pressure refrigerant flows. The high-pressure chamber (H) of the first cylinder chamber (54A) is isolated from the first suction passage (57A) and constitutes a compression chamber for compressing the refrigerant.(2-5-3) Details of Second Compression Element

[0055] The second compression element (C2) shown in FIG. 5 includes the second eccentric portion (32B), the second cylinder (51B), the second roller (52B), the second vane (53B), and a pair of second bushes (56B). The basic structures of the second eccentric portion (32B), the second cylinder (51B), the second roller (52B), the second vane (53B), and the pair of second bushes (56B) are the same as those of the first eccentric portion (32A), the first cylinder (51A), the first roller (52A), the first vane (53A), and the pair of first bushes (56A), respectively. Detailed description thereof will thus be omitted. The second cylinder (51B) is provided with the second cylinder chamber (54B), a second suction passage (57B), and a second bush groove (58B). The basic structures of the second cylinder chamber (54B), the second suction passage (57B), and the second bush groove (58B) are the same as those of the first cylinder chamber (54A), the first suction passage (57A), and the first bush groove (58A), respectively. Detailed description thereof will thus be omitted. The second suction pipe (23B) communicates with the second suction passage (57B). The first roller (52A) and the second roller (52B) are different in phase by 180° in the eccentric rotation.(2-6) Oil Supply Mechanism

[0056] The oil supply mechanism (70) shown in FIG. 3 supplies the refrigerating machine oil in the oil reservoir (35) to a plurality of sliding portions. The oil supply mechanism (70) is provided under the rotary shaft (30). The oil supply mechanism (70) includes an oil supply pump (71) and an oil supply passage (72).

[0057] The oil supply pump (71) is provided at the lower end of the rotary shaft (30). The oil supply pump (71) is located at a position lower than the oil level of the oil reservoir (35). The oil supply pump (71) transports the refrigerating machine oil in the oil reservoir (35). The oil supply pump (71) has a suction port (71a) for sucking the refrigerating machine oil in the oil reservoir (35). The suction port (71a) is open downward toward the bottom of the casing (21). The oil supply pump (71) is a differential pressure, centrifugal, or positive-displacement pump.

[0058] The rotary shaft (30) has therein the oil supply passage (72). The oil supply passage (72) communicates with the discharge side of the oil supply pump (71). The oil supply passage (72) includes a main flow passage (73) extending in the vertical direction so as to pass through the axis of the rotary shaft (30), and a plurality of flow divider passages extending from the main flow passage (73) in the radial direction. The plurality of flow divider passages include the first flow divider passage (74a), the second flow divider passage (74b), the third flow divider passage (74c), and the fourth flow divider passage (74d) in order from the top to the bottom.

[0059] The first flow divider passage (74a) is located at the same level as the upper bearing portion (41b). The outflow port of the first flow divider passage (74a) is open toward the first bearing (44). In other words, the first flow divider passage (74a) is open toward the sliding portion between the first bearing (44) and the rotary shaft (30). The second flow divider passage (74b) is formed in the first eccentric portion (32A). The outflow port of the second flow divider passage (74b) is open toward the inner circumferential surface of the first roller (52A). In other words, the second flow divider passage (74b) is open toward the sliding portion between the first roller (52A) and the first eccentric portion (32A). The third flow divider passage (74c) is formed in the second eccentric portion (32B). The outflow port of the third flow divider passage (74c) is open toward the inner circumferential surface of the first roller (52A). In other words, the third flow divider passage (74c) is open toward the sliding portion between the second roller (52B) and the second eccentric portion (32B). The fourth flow divider passage (74d) is at the same level as the lower bearing portion (43b). The outflow port of the fourth flow divider passage (74d) is open toward the second bearing (45). In other words, the fourth flow divider passage (74d) is open toward the sliding portion between the second bearing (45) and the rotary shaft (30).(2-7) Operation

[0060] Once the rotary shaft (30) is driven to rotate by the electric motor (25), the first eccentric portion (32A) and the second eccentric portion (32B) rotate eccentrically. In the first compression element (C1), the low-pressure refrigerant is sucked through the first suction pipe (23A) into the low-pressure chamber (L) of the first cylinder chamber (54A) in accordance with the eccentric rotation of the first roller (52A). At the same time, the refrigerant is compressed in the high-pressure chamber (H) of the first cylinder chamber (54A). In the second compression element (C2), the low-pressure refrigerant is sucked through the second suction pipe (23B) into the low-pressure chamber (L) of the first cylinder chamber (54A) in accordance with the eccentric rotation of the second roller (52B). At the same time, the refrigerant is compressed in the high-pressure chamber of the second cylinder chamber (54B).

[0061] Once the internal pressure of the compression chamber of the first compression element (C1) rises and the first reed valve opens, the high-pressure refrigerant is discharged through the first discharge port (55A) to the internal space (S). Once the internal pressure of the compression chamber of the second compression element (C2) rises and the second reed valve opens, the high-pressure refrigerant is discharged through the second discharge port (55B) to the internal space (S). The high-pressure refrigerant around the compression mechanism (40) passes upward through the electric motor (25) and is discharged through the discharge pipe (24) to the refrigerant circuit (10).

[0062] Once the rotary shaft (30) rotates, the oil supply pump (71) rotates together with the rotary shaft (30). As a result, the refrigerating machine oil in the oil reservoir (35) is sucked in through the suction port (71a). The oil supply pump (71) sends the refrigerating machine oil sucked through the suction port (71a) via the main flow passage (73) to the flow divider passages (74a, 74b, 74c, and 74d). The refrigerating machine oil in the first flow divider passage (74a) is used for lubricating the sliding portion of the first bearing (44). The refrigerating machine oil in the second flow divider passage (74b) is used for lubricating the sliding portion of the first eccentric portion (32A). The refrigerating machine oil in the third flow divider passage (74c) is used for lubricating the sliding portion of the second eccentric portion (32B). The refrigerating machine oil in the fourth flow divider passage (74d) is used for lubricating the sliding portion of the second bearing (45).(3) Refrigerant

[0063] The refrigerant according to this embodiment is a hydrocarbon refrigerant. The hydrocarbon refrigerant according to this embodiment is a single component refrigerant composed of propane (R290). Propane has a significantly low global warming potential and is environmentally friendly. On the other hand, a hydrocarbon refrigerant, such as propane, has a molecular structure similar to that of the refrigerating machine oil and thus has characteristics of being easily dissolvable in the refrigerating machine oil.

[0064] The hydrocarbon refrigerant may be a single component refrigerant composed of isobutane. The refrigerant of the refrigerant circuit (10) may be a refrigerant mixture containing the hydrocarbon refrigerant and at least one of other refrigerants. As the other refrigerant, for example, a hydrofluorocarbon (HFC) refrigerant, a hydrofluoroolefin (HFO) refrigerant, or trifluoroiodomethane (CF 3 I) is used.(4) Refrigerating Machine Oil

[0065] Next, the refrigerating machine oil used in the refrigerant circuit (10) will be described. Note that the refrigerating machine oil referred to here means a fluid containing additives, such as an extreme pressure additive, an antioxidant, and an acid scavenger in addition to the component (i.e., the lubricating oil) used for lubricating the sliding portions.

[0066] The refrigerating machine oil used in the refrigerant circuit (10) according to this embodiment includes any of polyalkylene glycol (PAG), polyvinyl ether (PVE), or polyol ester (POE). The refrigerating machine oil contains PAG, PVE or POE as a main component.

[0067] A hydrocarbon refrigerant, such as propane, has a molecular structure similar to that of the refrigerating machine oil and thus has characteristics of being easily dissolvable in the refrigerating machine oil. In contrast, PAG, PVE, or POE has a relatively low compatibility with a hydrocarbon refrigerant. Using PAG, PVE, or POE as the refrigerating machine oil, the dissolution of the refrigerant in the refrigerating machine oil can be reduced. The refrigerating machine oil may be alkylbenzene or mineral oil.

[0068] The refrigerating machine oil has characteristics of being separated into two layers at a pressure of the refrigerant of 1.9 [MPa] and a temperature of the refrigerating machine oil of 75°C. That is, the refrigerating machine oil in the oil reservoir (35) is separated into two layers when the refrigerant in the casing (21) has a pressure of 1.9 [MPa] and a temperature of 75[°C].

[0069] In general, the refrigerating machine oil uniformly dissolves in the refrigerant. However, when the refrigerating machine oil with a low solubility to the refrigerant is used, the concentration gradient occurs between the refrigerating machine oil and the refrigerant in the oil reservoir (35), and the refrigerating machine oil then becomes a so-called two-layer separation state. The refrigerating machine oil near the oil level of the oil reservoir (35) forms a layer with a high solubility for the refrigerant because the refrigerant has low density. The refrigerating machine oil near the bottom of the oil reservoir (35) forms a layer with a low solubility for the refrigerant because the refrigerant has high density. The solution viscosity of the refrigerating machine oil changes in accordance with the solubility of the refrigerant. The solution viscosity of the refrigerating machine oil can thus be secured by lowering the solubility to the refrigerant. The state in which the refrigerant and the refrigerating machine oil do not dissolve and are separated into two layers, or in which the refrigerant and the refrigerating machine oil are emulsified, when the refrigerant and the refrigerating machine oil are mixed, is referred to as the two-layer separation state.

[0070] The molecular weight of the refrigerating machine oil is preferably 1000 or more and 1800 or less.

[0071] The refrigerating machine oil includes at least one additive of an extreme pressure additive of a phosphoric acid ester, an antioxidant, or an acid scavenger.

[0072] As the extreme pressure additive of phosphoric acid ester, one of those containing phosphoric acid ester, phosphorous acid ester, acidic phosphoric acid ester, acidic phosphorous acid ester, and amine salt of acidic phosphorous acid ester may be used.

[0073] As the acid scavenger, an epoxy compound, such as phenyl glycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl ether, cyclohexene oxide, α-olefin oxide, or epoxidized soybean oil may be used.

[0074] As the antioxidant, a phenol-based antioxidant or an amine-based antioxidant can be used.

[0075] The refrigerating machine oil contains an extreme pressure additive in an amount of 1.0 wt% or more and 5.0 wt% or less. The refrigerating machine oil contains an antioxidant or an acid scavenger in an amount of 0.1 wt% or more and 0.5 wt% or less.

[0076] The surface tension of the refrigerating machine oil according to this embodiment is 0.25 [N / m] or more and 0.40 [N / m] or less at 20°C. The surface tension of the refrigerating machine oil is measured by a method in accordance with JIS K 2241.(5) Various Parameters of Compressor(5-1) Problems

[0077] A hydrocarbon refrigerant, such as propane, has a molecular structure similar to that of the refrigerating machine oil and thus has characteristics of being easily dissolvable in the refrigerating machine oil. Once the refrigerant dissolves in the refrigerating machine oil, the solution viscosity of the refrigerating machine oil decreases and the viscous resistance of the refrigerating machine oil decreases. As a result, the refrigerating machine oil in the casing (21) is likely to flow out of the discharge pipe (24) to the refrigerant circuit (10) together with the refrigerant, and an oil carryover rate may increase.

[0078] In addition, since a hydrocarbon refrigerant is highly flammable, the amount of the refrigerant filling the refrigerant circuit (10) may be limited in view of the risk of leakage of the refrigerant. However, since a hydrocarbon refrigerant is easily dissolvable in the refrigerating machine oil, the internal space (S) of the compressor (20) holds a larger amount of the refrigerant together with the refrigerating machine oil. This causes a shortage of refrigerant used in the refrigeration cycle of the refrigerant circuit (10). In particular, in the case of a separate type air conditioner (1) in which the indoor unit (IU) and the outdoor unit (OU) are separated from each other has a relatively long pipe length for the refrigerant. Such the problem of the shortage of the refrigerant becomes thus significant.(5-2) Outline of Relational Expressions

[0079] In order to solve the above problem, the compressor (20) according to this embodiment satisfies the following relationships between parameters.

[0080] The displacement volume of the compression mechanism (40) is defined as Vc [cc], the density of the refrigerant at 1.9 MPa and 75°C as Dg [g / cm 3< ], the number of revolutions of the rotary shaft (30) as N [rps], the volume of the primary space (S1) as V1 [cc], the volume of the secondary space (S2) as V2 [cc], the height of the primary space (S1) as H1 [cm], the height of the secondary space (S2) as H2 [cm], the overall height of the casing (21) as Hc [cm], the density of the refrigerating machine oil at 15°C as Do [g / cm 3< ], the solution viscosity of the refrigerating machine oil present at the level of the suction port (71a) or lower as η [mPa·S], and the oil carryover rate of the rotary compressor as α (wt%).

[0081] The compressor (20) according to this embodiment satisfies the following Expressions (1), (2), (3), and (4). N ≥ 100 H 2 / Hc ≤ 0.25 0.2 ≤ H 2 / Hc(5-3) Description of Parameters

[0082] The oil carryover rate α is the ratio of the weight Wo of the refrigerating machine oil to the total weight Wt of the fluid flowing out of the discharge pipe (24), expressed in percentage (α = Wo / Wt × 100).

[0083] With an increase in the number N of revolutions of the rotary shaft (30), the amount of refrigerant circulating in the refrigerant circuit (10) increases, making it easier for the refrigerating machine oil to flow out of the casing (21) together with the refrigerant. That is, with an increase in the number N of revolutions, the oil carryover rate α increases. In this embodiment, the number N of revolutions is 100 [rps] or more, which is a relatively high speed, and the oil carryover rate is thus likely to increase.

[0084] The displacement volume Vc is the volume of the high-pressure chamber (i.e., the compression chamber) when the low-pressure chamber (L) is completely closed in the cylinder (51A, 51B) and the high-pressure chamber (i.e., the compression chamber) is defined, and corresponds to the maximum volume of the compression chamber. The compression mechanism (40) according to this embodiment is a two-cylinder compression mechanism. In this case, Vc defined here is the sum of the displacement volume Vc-1 of the first cylinder (51A) and the displacement volume Vc-2 of the second cylinder (51B). When the number of cylinders is n and the displacement volumes of the respective cylinders are Vc-n, Vc-n + 1, . . ., the displacement volume Vc is the sum of the displacement volumes Vc-n, Vc-n + 1,....

[0085] With an increase in the displacement volume Vc, the amount of refrigerant circulating in the refrigerant circuit (10) increases, making it easier for the refrigerating machine oil to flow out of the casing (21) together with the refrigerant. That is, with an increase in the displacement volume Vc, the oil carryover rate α increases.

[0086] With an increase in the number N of revolutions of the rotary shaft (30), the amount of refrigerant circulating in the refrigerant circuit (10) increases, making it easier for the refrigerating machine oil to flow out of the casing (21) together with the refrigerant. That is, with an increase in the number N of revolutions, the oil carryover rate α increases. The number N of revolutions is preferably 120 [rps] or more, more preferably 150 [rps] or more. The number N of revolutions may be larger than or equal to the maximum number Nmax of revolutions of the compressor (20). The maximum number Nmax of revolutions is a predetermined value of 100 rps or more, preferably 120 rps or more, more preferably 150 rps or more.

[0087] As shown in FIG. 6, the primary space (S1) is between the compression mechanism (40) and the electric motor (25). Strictly, the primary space (S1) is between the upper end surface of the first closing portion (41a) of the front head (41) and the lower ends of the stator (26) and the rotor (27) of the electric motor (25). The upper end surface of the first closing portion (40a) is a flat surface above the recess in which the first reed valve is disposed. The volume V1 of the primary space (S1) corresponds to the volume of this space. However, as indicated by the frame of the broken line L1 in FIG. 6, the volume V1 of the primary space (S1) is calculated without taking into account the presence of the upper bearing portion (41b) and the rotary shaft (30). With an increase in the volume V1, the refrigerant and the oil are easily separated from each other in the primary space (S1) and oil carryover rate α thus decreases.

[0088] H1 is the height of the primary space (S1). Strictly, as shown in FIG. 6, H1 is the maximum height between the upper end surface of the first closing portion (41a) of the front head (41) and the lower ends of the stator (26) and the rotor (27). With an increase in the height H1 of the primary space (S1), the refrigerant and the oil are easily separated from each other in the primary space (S1), and the oil carryover rate α thus decreases.

[0089] As shown in FIG. 6, the secondary space (S2) is above the electric motor (25). Strictly, the secondary space (S2) is between the upper ends of the stator (26) and the rotor (27) of the electric motor (25) and the top (i.e., the upper lid (21b)) of the casing (21). The volume V2 of the secondary space (S2) corresponds to the volume of this space. However, as indicated by the frame of the broken line L2 in FIG. 6, the volume V2 of the secondary space (S2) is calculated without taking into account the presence of the rotary shaft (30) and the discharge pipe (24). With an increase in the volume V2, the refrigerant and the oil are easily separated from each other in the secondary space (S2), and the oil carryover rate α thus decreases.

[0090] H2 is the height of the secondary space (S2). Strictly, as shown in FIG. 6, H2 is the maximum height between the upper ends of the stator (26) and the rotor (27) of the electric motor (25) and the top (i.e., the upper lid (21b)). With an increase in the height H2 of the secondary space (S2), the refrigerant and the oil are easily separated from each other in the secondary space (S2), and the oil carryover rate α thus decreases.

[0091] As shown in FIG. 2, the height Hc is the overall height of the casing (21). In other words, the height Hc is the maximum height from the lower end to the upper end of the casing (21).

[0092] With an increase in the density Dg of the refrigerant, the amount of refrigerant circulating in the refrigerant circuit (10) increases, making it easier for the refrigerating machine oil to flow out of the casing (21) together with the refrigerant. That is, with a decrease in the density Dg of the refrigerant, the oil carryover rate α decreases.

[0093] In this embodiment, the density Dg of the refrigerant is 37 [g / cm 3< ] or more and 44 [g / cm 3< ] or less. The density Dg of the refrigerant is smaller than the density of the HFC refrigerant, for example. By reducing the density Dg of the refrigerant in this manner, the oil carryover rate α can be reduced.

[0094] The density Do of the refrigerating machine oil is the density of the refrigerating machine oil. With an increase in the density of the refrigerating machine oil, the refrigerating machine oil is less likely to flow out of the casing (21), and the oil carryover rate α decreases.

[0095] The solution viscosity η of the refrigerating machine oil is the solution viscosity of the refrigerating machine oil (hereinafter also referred to as first refrigerating machine oil), located at the level h1 of the suction port (71a) of the oil supply pump (71) or lower in the oil reservoir (35). As shown in FIG. 3, the level h1 of the suction port (71a) means an absolute height of the horizontal plane passing through the suction port (71a). The "solution viscosity" means the viscosity of a fluid with the refrigerant dissolved in the refrigerating machine oil. This viscosity of the fluid is measured by a method in accordance with JIS K 2283. The solution viscosity of the refrigerating machine oil changes in accordance with the content of the extreme pressure additive, the antioxidant, or the oxygen scavenger described above.

[0096] With a decrease in the solution viscosity η, the viscous resistance of the refrigerating machine oil decreases, making it easier for the refrigerating machine oil to flow out of the casing (21). That is, by increasing the solution viscosity η, the oil carryover rate α is reduced.

[0097] The solution viscosity η is preferably 5.0 or more. This is because when the solution viscosity η is lower than 5.0, the amounts of wear at the sliding portion of the bearings (44, 45) and the sliding portion of the eccentric portions (32A, 32B) rapidly increase. In addition, by increasing the solution viscosity η in this manner, the oil carryover rate α can be reduced.

[0098] The solution viscosity η is preferably 1.2 or less. If the solution viscosity η becomes excessively high, the sliding loss at the eccentric portion (32A, 32B) increases, leading to a decrease in the efficiency of the compressor (20). If the solution viscosity is 1.2 or less, the decrease in the efficiency of the compressor (20) can be suppressed.

[0099] As described above, the parameters influence the oil carryover rate α. As a result of verification, the present inventors have confirmed that the oil carryover rate α can be expressed by Expression (2). Thus, by satisfying the Expressions (1) and (2) (α = 1.0), the oil carryover rate α can be reduced to 1.0 or less, even when the compressor (20) operates at a number N of revolutions of 100 [rps] or more.

[0100] In this embodiment, H2 / Hc ≤ 0.25 as shown in Expression (3). With an excessively large height of the secondary space (S2) relative to the overall length of the casing (21), the volume of the secondary space (S2) increases. As described above, since the hydrocarbon refrigerant is easily dissolvable in the refrigerating machine oil, the amount of refrigerant held in the secondary space (S2) tends to increase particularly easily as the volume of the secondary space (S2) increases. In contrast, by setting the height ratio to H2 / Hc ≤ 0.25, the volume of the secondary space (S2) is reduced. As a result, the amount of the refrigerant held in the secondary space (S2) can be reduced. Accordingly, the amount of the refrigerant used in the refrigeration cycle can be secured, even if the amount of the refrigerant filling the refrigerant circuit (10) is limited. In other words, a normal refrigeration cycle can be performed, and the amount of the refrigerant filling the refrigerant circuit (10) can be reduced.

[0101] In this embodiment, 0.2 ≤ H2 / Hc shown in Expression (4) is satisfied. If the height H2 of the secondary space (S2) is excessively low, the oil separation ratio in the secondary space (S2) decreases, and the oil carryover rate α increases. In contrast, by setting the height ratio to 0.2 ≤ H2 / Hc, the function of separating the refrigerating machine oil in the secondary space (S2) can be ensured, and the oil carryover rate α can be reduced.(6) Advantages of Embodiment(6-1)

[0102] The refrigerant according to this embodiment is a hydrocarbon refrigerant. The rotary compressor satisfies relational expressions: N ≥ 100 [rps]; and where α is 1.0.

[0103] This configuration can reduce the oil carryover rate α to 1.0 or less, when the compressor (20) operates at the number N of revolutions of 100 [rps] or more. This can reduce the shortage of the refrigerating machine oil supplied to the bearing (44, 45) and the eccentric portion (32A, 32B), thereby increasing the reliability of the compressor (20).(6-2)

[0104] The compressor (20) according to this embodiment satisfies the relational expression H2 / Hc ≤ 0.25. This can reduce the amount of the refrigerant held in the secondary space (S2). Accordingly, the shortage of the refrigerant to be used in the refrigeration cycle can be reduced, while limiting the amount of the refrigerant filling the refrigerant circuit (10).(6-3)

[0105] The compressor (20) according to this embodiment satisfies the relational expression 0.2 ≤ H2 / Hc. This can ensure the function of separating oil in the secondary space (S2), thereby reducing the oil carryover rate.(6-4)

[0106] The refrigerating machine oil includes polyalkylene glycol, polyvinyl ether, or polyol ester.

[0107] With the use of these refrigerating machine oils, the hydrocarbon refrigerant is less likely to dissolve in the refrigerating machine oil. This can reduce a decrease in the viscous resistance of the refrigerating machine oil, and can thus reduce the oil carryover rate. In addition, the solution viscosity of the first refrigerating machine oil does not become excessively low, and the wear at the sliding portions can thus be reduced. In particular, by setting the molecular weight of the refrigerating machine oil to 1000 or more and 1800 or less, the dissolution of the hydrocarbon refrigerant in the refrigerating machine oil can be effectively reduced.

[0108] In addition, by reducing the dissolution of the hydrocarbon refrigerant in the refrigerating machine oil in this manner, the amount of the refrigerant held in the casing (21) is reduced. Accordingly, the shortage of the refrigerant to be used in the refrigeration cycle can be reduced, while limiting the amount of the refrigerant filling the refrigerant circuit (10).(6-5)

[0109] The refrigerating machine oil contains at least one of an extreme pressure additive of a phosphoric acid ester, an antioxidant, or an acid scavenger.

[0110] When the refrigerating machine oil contains an antioxidant, the amount of the antioxidant in the refrigerating machine oil is 0.1 wt% or more and 0.5 wt% or less. The hydrocarbon refrigerant has a chemically stable structure and is less likely to decompose during the refrigeration cycle compared to HFC refrigerant and HFO refrigerant. Even when the amount of the antioxidant in the refrigerant is 0.5 wt% or less, the refrigerant can be stably used for a long period of time. By limiting the amount of the antioxidant to 0.5 wt% or less, a decrease in the viscosity of the refrigerating machine oil can be reduced. As a result, the viscous resistance of the refrigerating machine oil increases, and the oil carryover rate α can thus be reduced. In addition, the wear at the sliding portions can be reduced.

[0111] When the refrigerating machine oil contains an acid scavenger, the amount of the acid scavenger is 0.1 wt% or more and 0.5 wt% or less. As described above, the hydrocarbon refrigerant has a chemically stable structure and is less likely to decompose during the refrigeration cycle compared to HFC refrigerant and HFO refrigerant. Even when the amount of the acid scavenger in the refrigerant is 0.5 wt% or less, the refrigerant can be stably used for a long period of time. By limiting the amount of the antioxidant to 0.5 wt% or less, a decrease in the viscosity of the refrigerating machine oil can be reduced. As a result, the viscous resistance of the refrigerating machine oil increases, and the oil carryover rate α can thus be reduced. In addition, the wear at the sliding portions can be reduced.

[0112] When the refrigerating machine oil contains an extreme pressure additive, the amount of the extreme pressure additive is 1.0 wt% or more and 5.0 wt%. By limiting the amount of the extreme pressure additive to 5.0 wt% or less, a decrease in the viscosity of the refrigerating machine oil can be reduced. As a result, the viscous resistance of the refrigerating machine oil increases, and the oil carryover rate α can thus be reduced. In addition, the wear at the sliding portions can be reduced.(7) Other Embodiments

[0113] The rotary compressor may be of a so-called rolling piston type in which the roller eccentrically rotates with a vane separate from the roller abutting on the roller. The rotary compressor may be of a so-called hinge vane type in which the roller eccentrically rotates with the tip of the vane rotatably fitted into the recess of the outer circumferential surface of the roller.

[0114] The compression mechanism (40) may include only one cylinder, or may include three or more cylinders. In other words, the compression mechanism (40) may include only one compression unit, or may include three or more compression units.

[0115] The air conditioner (1) may be of a multi-indoor type having a plurality of indoor units. The air conditioner (1) may be of a movable type that adjusts the temperature of air in a target space of a vehicle, for example. The refrigeration cycle apparatus may be a hot water supply apparatus for generating hot water or a cooling apparatus for generating cold water. The refrigeration cycle apparatus may be an internal cooling apparatus that cools inside air. The internal cooling apparatus may be a stationary type for a warehouse, or a movable type for the inside of a transport container or a trailer.

[0116] The rotary compressor (20) may satisfy only the Expressions (1) and (2) described above, but further satisfies the Expression (3) or (4) in one preferred embodiment.

[0117] The first refrigerating machine oil is located at the level of the suction port (71a) or lower in the oil reservoir (35). However, it is preferable that the first refrigerating machine oil is present below the suction port (71a), near the suction port (71a), or inside the suction port (71a).

[0118] While the embodiments and the variation 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.

[0119] The expressions of "first," "second," "third," ... described above are used to distinguish the words to which these expressions are given, and the number and order of the words are not limited.INDUSTRIAL APPLICABILITY

[0120] As described above, the present disclosure is useful for a rotary compressor and a refrigeration cycle apparatus.DESCRIPTION OF REFERENCE CHARACTERS

[0121] 1Air Conditioner (Refrigeration Cycle Apparatus) 10Refrigerant Circuit 20Compressor 21Casing 24Discharge Pipe 25Electric Motor 30Rotary Shaft 40Compression Mechanism 51A, 51BCylinder 52A, 52BRoller 53A, 53BVane 70Oil Supply Mechanism 71aSuction Port SInternal Space S1Primary Space S2Secondary Space

Claims

1. A compressor comprising: an electric motor (25); a rotary shaft (30) connected to the electric motor (25); a compression mechanism (40) disposed below the electric motor (25) and configured to be driven by the rotary shaft (30) and compress a refrigerant; a casing (21) configured to house the electric motor (25), the rotary shaft (30), and the compression mechanism (40) and filled with a high-pressure refrigerant discharged from the compression mechanism (40); and an oil supply mechanism (70) having a suction port (71a) for sucking the refrigerating machine oil accumulated at a bottom of the casing (21) and configured to supply the refrigerating machine oil to a sliding portion, wherein the compression mechanism (40) includes an annular cylinder (51A, 51B), an annular roller (52A, 52B) configured to eccentrically rotate in the cylinder (51A, 51B), and a vane (53A, 53B) for defining a compression chamber in the cylinder (51A, 51B), the internal space (S) of the casing (21) includes a primary space (S1) between the compression mechanism (40) and the electric motor (25), and a secondary space (S2) above the electric motor (25), a discharge pipe (24) communicating with the secondary space (S2) is connected to the casing (21), the refrigerant is a single component refrigerant composed of a hydrocarbon refrigerant or a refrigerant mixture containing the hydrocarbon refrigerant, when a displacement volume of the compression mechanism (40) is defined as Vc [cc], a density of the refrigerant at 1.9 Mpa and 75°C as Dg [g / cm3], a number of revolutions of the rotary shaft (30) as N [rps], a volume of the primary space (S1) as V1 [cc], a volume of the secondary space (S2) as V2 [cc], a height of the primary space (S1) as H1 [cm], a height of the secondary space (S2) as H2 [cm], a density of the refrigerating machine oil at 15°C as Do [g / cm3], and a solution viscosity of the refrigerating machine oil present at a level of the suction port (71a) or lower as η [mPa·S], relational expressions N ≥ 100 [rps], and are satisfied.

2. The compressor of claim 1, wherein when an overall height of the casing (21) is defined as Hc [cm], H 2 / Hc ≤ 0.25 .

3. The compressor of claim 1 or 2, wherein when an overall height of the casing (21) is defined as Hc [cm], 0.2 ≤ H 2 / Hc .

4. The compressor of any one of claims 1 to 3, wherein the refrigerating machine oil includes polyalkylene glycol, polyvinyl ether, or polyol ester.

5. The compressor of any one of claims 1 to 4, wherein a density Do [g / cm3] of the refrigerant is 37 [g / cm3] or more and 44 [g / cm3] or less.

6. The compressor of any one of claims 1 to 5, wherein the refrigerating machine oil contains at least one of an extreme pressure additive of a phosphoric acid ester, an antioxidant, or an acid scavenger.

7. The compressor of any one of claims 1 to 6, wherein the refrigerating machine oil contains the antioxidant or the acid scavenger in an amount of 0.1 wt% or more and 0.5 wt% or less.

8. The compressor of any one of claims 1 to 7, wherein the refrigerating machine oil contains the extreme pressure additive in an amount of 1.0 wt% or more and 5.0 wt% or less.

9. The compressor of any one of claims 1 to 8, wherein the refrigerating machine oil has a molecular weight of 1000 or more and 1800 or less.

10. A refrigeration cycle apparatus comprising: a refrigerant circuit (10) including the rotary compressor (20) of any one of claims 1 to 9, and configured to perform a refrigeration cycle using the hydrocarbon refrigerant.

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