Accumulator, compressor, and refrigeration cycle apparatus

Abstract

An accumulator 7 includes: a container 61; a partition plate 62 dividing an internal space S of the container 61 into a refrigerant introduction chamber IR and a refrigerant discharge chamber OR; an inlet pipe 63 including an inlet flow channel IP connected to the refrigerant introduction chamber IR; at least one communication pipe 65 including a communication flow channel CP passing through the partition plate 62 to connect the refrigerant introduction chamber IR with the refrigerant discharge chamber OR; and at least one outlet pipe 66 including an outlet flow channel OP connected to the refrigerant discharge chamber OR. The communication pipe 65 includes at least one introduction-side refrigerating machine oil return hole 65d disposed in the refrigerant introduction chamber IR. The outlet pipe 66 includes at least one discharge-side refrigerating machine oil return hole 66d disposed in the refrigerant discharge chamber OR. Oil returning capability of the discharge-side refrigerating machine oil return hole 66d is higher than that of the introduction-side refrigerating machine oil return hole 65d.

Description

BACKGROUND OF THE INVENTION Field of the Invention

[0001] Embodiments according to the present invention relate to an accumulator, a compressor, and a refrigeration cycle apparatus.Description of the Related Art

[0002] To prevent a liquid refrigerant from being supplied into and compressed in a cylinder of a compressor, what is called liquid compression, there is known an accumulator (gas-liquid separator, liquid separator) disposed on a suction side of the compressor (for example, Japanese Patent Laid-Open No. H04-350479).

[0003] To secure gas-liquid separation capacity, a conventional accumulator includes a container, a partition plate that divides an internal space of the container into upper and lower spaces, a straight pipe that vertically extends to passe through the partition plate to open in a bottom space, and an outlet pipe that opens in the bottom space to be led out from a lower surface of the container.

[0004] A lower end of the straight pipe, that is, an outlet end of the straight pipe, is disposed in a vicinity of the partition plate. An upper end of the outlet pipe, that is, an inlet end of the outlet pipe, is disposed in a vicinity of a bottom plate of the container. That is, the outlet end of the straight pipe is disposed above the inlet end of the outlet pipe.SUMMARY OF THE INVENTION

[0005] In the conventional accumulator, when a liquid refrigerant flows into the bottom space of the container through the straight pipe, this liquid refrigerant easily flows into the outlet pipe having the inlet end in the vicinity of the bottom plate of the container. This may cause liquid compression in the compressor.

[0006] On the other hand, the accumulator temporarily catches refrigerating machine oil that is discharged from the compressor together with the refrigerant and circulates in a refrigerating cycle to return to the compressor, and returns the caught refrigerating machine oil to the compressor. At this point, similarly to the liquid compression of the refrigerant, it is not preferable that the refrigerating machine oil at an excessive flow rate returns to the compressor from the accumulator.

[0007] Thus, an object of the present invention is to provide an accumulator, a compressor including this accumulator, and a refrigeration cycle apparatus, wherein the accumulator can achieve both of gas-liquid separation capacity that can securely prevent a liquid refrigerant from flowing out, in other words, gas-liquid separation capacity that can securely prevent liquid compression in the compressor, and adjustment of an oil return flow rate to return caught refrigerating machine oil to the compressor at an appropriate flow rate.

[0008] To resolve the above problems, an accumulator according to an embodiment of the present invention includes: a container; a partition plate that is disposed inside the container, and divides an internal space of the container into a refrigerant introduction chamber and a refrigerant discharge chamber; an inlet pipe that is fixed to the container and includes an inlet flow channel connected to the refrigerant introduction chamber; at least one communication pipe including a communication flow channel that passes through the partition plate to connect the refrigerant introduction chamber with the refrigerant discharge chamber; and at least one outlet pipe that is fixed to the container and includes an outlet flow channel connected to the refrigerant discharge chamber. The at least one communication pipe includes an outlet opening disposed in the refrigerant discharge chamber and at least one introduction-side refrigerating machine oil return hole disposed in the refrigerant introduction chamber. The at least one outlet pipe includes an inlet opening disposed in the refrigerant discharge chamber and at least one discharge-side refrigerating machine oil return hole disposed in the refrigerant discharge chamber. Oil returning capability of the at least one discharge-side refrigerating machine oil return hole is higher than oil returning capability of the at least one introduction-side refrigerating machine oil return hole.

[0009] To resolve the above problems, a compressor according to another embodiment of the present invention includes: a sealed container; a compression mechanism housed in the sealed container; an electric motor that is housed in the sealed container and generates driving force of the compression mechanism; and the accumulator that is placed outside the sealed container and connected to a suction side of the compression mechanism.

[0010] To resolve the above problems, a refrigeration cycle apparatus according to another embodiment of the present invention includes: the compressor; a radiator; an expansion device; a heat absorber; and a refrigerant piping that connects the compressor, the radiator, the expansion device, and the heat absorber to circulate a refrigerant.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Fig. 1 is a schematic diagram of a refrigeration cycle apparatus, a compressor, and an accumulator according to embodiments of the present invention; Fig. 2 is a first vertical cross-sectional view of the accumulator according to the embodiment of the present invention; Fig. 3 is a second vertical cross-sectional view of the accumulator according to the embodiment of the present invention; Fig. 4 is a horizontal cross-sectional view of the accumulator according to the embodiment of the present invention; Fig. 5 is a diagram for comparing the accumulator according to the present embodiment with a conventional accumulator in a supercharging effect; Fig. 6 is a diagram illustrating a relation between a cross-sectional area of a communication flow channel and a cross-sectional area of an outlet flow channel of the accumulator according to the present embodiment; and Fig. 7 is a vertical cross-sectional view of another aspect of the accumulator according to the embodiment of the present invention. DETAILED DESCRIPTION

[0012] The following describes embodiments of an accumulator, a compressor, and a refrigeration cycle apparatus according to the present invention with reference to Fig. 1 to Fig. 6. Throughout a plurality of drawings, same or corresponding configurations are denoted by the same reference numeral.

[0013] Fig. 1 is a schematic diagram of the refrigeration cycle apparatus, the compressor, and the accumulator according to the embodiment of the present invention.

[0014] As illustrated in Fig. 1, a refrigeration cycle apparatus 1 according to the present embodiment includes a rotary compressor 2, a radiator 3, an expansion device 5, a heat absorber 6, an accumulator 7, and a refrigerant piping 8. The rotary compressor 2 is simply referred to as a "compressor 2" hereinafter. The refrigerant piping 8 successively connects the compressor 2, the radiator 3, the expansion device 5, the heat absorber 6, and the accumulator 7 to circulate a refrigerant. The refrigerant that circulates in the refrigeration cycle apparatus 1 is any of various refrigerants such as a carbon dioxide refrigerant, a R32 refrigerant, and a mixed refrigerant including R32 refrigerant. The radiator 3 may also be called a condenser, and the heat absorber 6 may also be called an evaporator.

[0015] The compressor 2 includes a cylindrical-shaped sealed container 11 that is vertically disposed, an electric motor 12 housed in an upper half portion of the sealed container 11, a compression mechanism 13 housed in a lower half portion of the sealed container 11, a crank shaft 15 that transmits rotational driving force of the electric motor 12 to the compression mechanism 13, and a main bearing 16 and an auxiliary bearing 17 cooperating with each other to support the crank shaft 15 in a rotatable manner.

[0016] The sealed container 11 has a cylindrical shape. The sealed container 11 includes a cylindrical-shaped drum 11a extending in an upper and lower direction, a hemispherical-shaped or elliptical-shaped upper end plate 11b that blocks an upper end portion of the drum 11a, and a hemispherical-shaped or elliptical-shaped lower end plate 11c that blocks a lower end portion of the drum 11a.

[0017] The drum 11a supports a plurality of suction pipes 8b guiding the refrigerant to the compressor 2. The suction pipes 8b are connected to the accumulator 7. The suction pipes 8b are part of the refrigerant piping 8.

[0018] The upper end plate 11b supports a discharge pipe 8a that discharges the refrigerant compressed by the compressor 2. The discharge pipe 8a is connected to the refrigerant piping 8. The upper end plate 11b includes a sealed terminal portion 18 that supplies electric power to the electric motor 12.

[0019] The electric motor 12 generates driving force to rotate the compression mechanism 13. The electric motor 12 is, for example, a Permanent Magnet Synchronous Motor (PMSM). The electric motor 12 includes a tubular-shaped stator 21 fixed to an inner wall of the sealed container 11, a rotor 22 that is disposed on an inner side of the stator 21 and fixed to the crank shaft 15, and a plurality of lead wires 23 led out from the stator 21 and connected to the sealed terminal portion 18.

[0020] The rotor 22 includes a rotor core having a magnet housing hole, and a permanent magnet housed in the magnet housing hole. The rotor 22 can rotate with respect to the stator 21, and fixed to the crank shaft 15 to be integrally rotatable therewith. Rotation center lines of the rotor 22 and the crank shaft 15 substantially agree with a center line of the stator 21.

[0021] The lead wires 23 are wiring for supplying electric power to the stator 21 through the sealed terminal portion 18, what is called leads. The lead wires 23 are wired in accordance with a type of the electric motor 12. In a case in which the lead wires 23 are used as an open-winding type, two lead wires 23 are wired for each of a U-phase, a V-phase, and a W-phase, that is, the six lead wires 23 in total are wired. In a case in which the electric motor 12 is used with a star connection, one lead wire 23 is wired for each of the U-phase, the V-phase, and the W-phase, that is, the three lead wires 23 in total are wired.

[0022] The crank shaft 15 couples the electric motor 12 with the compression mechanism 13. The crank shaft 15 transmits driving force generated by the electric motor 12 to the compression mechanism 13.

[0023] An intermediate portion 15a of the crank shaft 15 connects the electric motor 12 with the compression mechanism 13, and is supported by the main bearing 16 in a rotatable manner. A lower end portion 15b of the crank shaft 15 is supported by the auxiliary bearing 17 in a rotatable manner. The main bearing 16 and the auxiliary bearing 17 are part of the compression mechanism 13. In other words, the crank shaft 15 passes through the compression mechanism 13.

[0024] The crank shaft 15 includes a plurality of eccentric portions 25a and 25b between the intermediate portion 15a supported by the main bearing 16 and the lower end portion 15b supported by the auxiliary bearing 17. Of the eccentric portions 25, a portion closer to the main bearing 16 is referred to as a first eccentric portion 25a, and a portion closer to the auxiliary bearing 17 is referred to as a second eccentric portion 25b. Each of the eccentric portions 25a and 25b is a disk or a cylinder having a center not agreeing with the center of the crank shaft 15. The center of each of the eccentric portions 25a and 25b is decentered with a phase difference of about 180 degrees around the crank shaft 15. The first eccentric portion 25a is placed on an upper side closer to the electric motor 12, and the second eccentric portion 25b is placed on a lower side distant from the electric motor 12.

[0025] The main bearing 16 on the upper side is fixed to a frame 14 via a first cylinder 32 by a plurality of fastening members, for example, bolts 51 and 52. The frame 14 is fixed to the sealed container 11 at a plurality of points by welding, for example, spot welding. That is, the frame 14 supports the compression mechanism 13, the crank shaft 15, and the rotor 22 of the electric motor 12 on the sealed container 11.

[0026] When the electric motor 12 coupled to the compression mechanism 13 via the crank shaft 15 is rotated and driven, the compression mechanism 13 sucks a gaseous refrigerant through the suction pipes 8b, compresses the sucked refrigerant, and discharges the compressed refrigerant into the sealed container 11. A lower portion of the sealed container 11 is filled with refrigerating machine oil, and a major portion of the compression mechanism 13 is immersed in the refrigerating machine oil.

[0027] The compression mechanism 13 includes more than one, for example, two rotor-cylinder assemblies 26 and 27. In other words, the compressor 2 is a multi-cylinder rotary compressor. The compression mechanism 13 includes the first rotor-cylinder assembly 26 disposed inside the sealed container 11, the second rotor-cylinder assembly 27 disposed inside the sealed container 11, and a partition plate 29 disposed between the first rotor-cylinder assembly 26 and the second rotor-cylinder assembly 27.

[0028] The compressor 2 may be a multi-cylinder rotary compressor having three or more cylinders, or may be a rotary compressor having a single cylinder. The compressor 2 and the accumulator 7 are connected via the suction pipes 8b the number of which is the same as the number of the cylinders.

[0029] The first rotor-cylinder assembly 26 includes the first cylinder 32 including a circular-shaped first cylinder chamber 31, and an annular-shaped first rolling piston 33 disposed inside the first cylinder chamber 31. The first rolling piston 33 is simply referred to as a "first piston 33" hereinafter.

[0030] The second rotor-cylinder assembly 27 includes a second cylinder 42 including a circular-shaped second cylinder chamber 41, and an annular-shaped second rolling piston 43 disposed inside the second cylinder chamber 41. The second rolling piston 43 is simply referred to as a "second piston 43" hereinafter.

[0031] Each of the rotor-cylinder assemblies 26 and 27 includes a vane 45 that partitions corresponding one of the cylinder chambers 31 and 41 into a suction chamber and a compression chamber by performing reciprocating motion for approaching or moving away from a rotation center line of the crank shaft 15 while being in contact with an outer peripheral surfaces of corresponding one of the pistons 33 and 43. Each of the rotor-cylinder assemblies 26 and 27 changes capacity of the compression chamber sectioned by corresponding one of the pistons 33 and 43 and the corresponding vane 45 by rotation of the pistons 33 and 43 to compress the refrigerant. Only the vane 45 of the second rotor-cylinder assembly 27 is illustrated in Fig. 1.

[0032] The first cylinder 32 and the second cylinder 42 are disposed to be stacked in an axis direction of the crank shaft 15. The first cylinder 32 on the upper side is disposed on a side closer to the electric motor 12. The second cylinder 42 on the lower side is disposed on a side distant from the electric motor 12.

[0033] Each of the cylinders 32 and 42 includes an inner peripheral surface that defines corresponding one of the cylinder chambers 31 and 41. Each of the cylinders 32 and 42 has an annular shape and a plate shape including corresponding one of the cylinder chambers 31 and 41 inside. Each of the cylinders 32 and 42 has an end face close to the electric motor 12 and an end face distant from the electric motor 12.

[0034] Centers of the first cylinder chamber 31 and the second cylinder chamber 41 substantially overlap the rotation center line of the crank shaft 15. These cylinder chambers 31 and 41 have substantially the same diameter dimension and height dimension, that is, a dimension in a length direction of the crank shaft 15. The first cylinder chamber 31 is a space inside the first cylinder 32, and closed by the main bearing 16 and the partition plate 29. The first cylinder chamber 31 houses the first eccentric portion 25a of the crank shaft 15. The second cylinder chamber 41 is a space inside the second cylinder 42, and closed by the partition plate 29 and the auxiliary bearing 17. The second cylinder chamber 41 houses the second eccentric portion 25b of the crank shaft 15.

[0035] The compression mechanism 13 includes a first discharge valve mechanism including a discharge port that is disposed on the main bearing 16 to discharge the refrigerant compressed inside the first cylinder chamber 31 to the outside of the first cylinder chamber 31 and a discharge valve that is disposed on the main bearing 16 to open and close the discharge port, and a first discharge muffler 55 that is disposed on the main bearing 16 to cover the first discharge valve mechanism.

[0036] The discharge port of the first discharge valve mechanism is connected to the first cylinder chamber 31.

[0037] The discharge valve of the first discharge valve mechanism opens the discharge port when a differential pressure between an inside and an outside of the first cylinder chamber 31 reaches a predetermined differential pressure value in association with compression action of the compression mechanism 13, and discharges the compressed refrigerant into the first discharge muffler 55.

[0038] The first discharge muffler 55 covers the first discharge valve mechanism. The first discharge muffler 55 has a discharge hole passing through the first discharge muffler 55. The compressed refrigerant discharged into the first discharge muffler 55 is discharged into the sealed container 11 through the discharge hole.

[0039] The first discharge muffler 55 and the first cylinder 32 are fixed to the main bearing 16 by a plurality of fastening members, for example, the bolts 52. The bolt 52 passes through the first discharge muffler 55 and the main bearing 16 to reach the first cylinder 32.

[0040] The compression mechanism 13 also includes a second discharge valve mechanism including a discharge port that is disposed on the auxiliary bearing 17 to discharge the refrigerant compressed inside the second cylinder chamber 41 and a discharge valve that is disposed on the auxiliary bearing 17 to open and close the discharge port, and a second discharge muffler 57 that is disposed on the auxiliary bearing 17 to cover the second discharge valve mechanism.

[0041] The discharge port of the second discharge valve mechanism is connected to the second cylinder chamber 41.

[0042] The discharge valve of the second discharge valve mechanism opens the discharge port when a differential pressure between an inside and an outside of the second cylinder chamber 41 reaches a predetermined differential pressure value in association with compression action of the compression mechanism 13, and discharges the compressed refrigerant into the second discharge muffler 57.

[0043] The second discharge muffler 57 covers the second discharge valve mechanism. The compressed refrigerant discharged into the second discharge muffler 57 is guided to the first discharge muffler 55 through a hole passing through the auxiliary bearing 17, the second cylinder 42, the partition plate 29, and the first cylinder 32, and discharged into the sealed container 11.

[0044] The second discharge muffler 57, the auxiliary bearing 17, the second cylinder 42, and the partition plate 29 are fixed to the first cylinder 32 by a plurality of fastening members, for example, bolts 58. The bolt 58 passes through the second discharge muffler 57, the auxiliary bearing 17, the second cylinder 42, and the partition plate 29 to reach the first cylinder 32.

[0045] The first piston 33 is engaged with a peripheral surface of the first eccentric portion 25a and housed in the first cylinder chamber 31. The first piston 33 eccentrically moves while causing part of the outer peripheral surface to be in line contact with an inner peripheral surface of the first cylinder chamber 31 in association with rotation of the crank shaft 15.

[0046] The second piston 43 is engaged with a peripheral surface of the second eccentric portion 25b and housed in the second cylinder chamber 41. The second piston 43 eccentrically moves while causing part of the outer peripheral surface to be in line contact with an inner peripheral surface of the second cylinder chamber 41 in association with rotation of the crank shaft 15.

[0047] Contact between the first piston 33 and the first cylinder 32, and contact between the second piston 43 and the second cylinder 42 are not direct contact but indirect contact with an oil film (not illustrated) interposed therebetween. For convenience of explanation, the contact via the oil film is simply referred to as "contact". The same applies to contact between the first piston 33 and the first eccentric portion 25a, contact between the second piston 43 and the second eccentric portion 25b, contact between the first piston 33 and the main bearing 16, contact between the second piston 43 and the auxiliary bearing 17, contact between the first piston 33 and the partition plate 29, and contact between the second piston 43 and the partition plate 29.

[0048] The accumulator 7 is fixed to the sealed container 11 of the compressor 2 with a clamp band 59.

[0049] Fig. 2 and Fig. 3 are vertical cross-sectional views of the accumulator according to the embodiment of the present invention.

[0050] As illustrated in Fig. 2 and Fig. 3 in addition to Fig. 1, the accumulator 7 according to the present embodiment includes a cylindrical-shaped container 61 supported in an upright state, a partition plate 62 that is disposed inside the container 61 to divide an internal space S of the container 61 into a refrigerant introduction chamber IR and a refrigerant discharge chamber OR, an inlet pipe 63 that is fixed to the container 61 and has an inlet flow channel IP connected to the refrigerant introduction chamber IR, at least one communication pipe 65 that passes through the partition plate 62 and has a communication flow channel CP connecting the refrigerant introduction chamber IR with the refrigerant discharge chamber OR, and a plurality of outlet pipes 66 fixed to the container 61 and each having an outlet flow channel OP connected to the refrigerant discharge chamber OR.

[0051] The accumulator 7 also includes a strainer 71 that is disposed between the inlet pipe 63 and the communication pipe 65 to filter out foreign substances from the refrigerant introduced into the accumulator 7, a separation plate 72 that is disposed between the strainer 71 and the communication pipe 65 to separate the refrigerant passed through the strainer 71 into a gas refrigerant and a liquid refrigerant, and a supporting plate 73 that is disposed between the separation plate 72 and the partition plate 62 to support the communication pipe 65 together with the partition plate 62.

[0052] The container 61 is fixed to the sealed container 11 of the compressor 2 with the clamp band 59. The container 61 has a cylindrical shape. The container 61 includes a cylindrical-shaped drum 61a extending in the upper and lower direction, a hemispherical-shaped or elliptical-shaped upper end plate 61b that blocks an upper end portion as one end portion of the drum 61a, and a hemispherical-shaped or elliptical-shaped lower end plate 61c that blocks a lower end portion as another end portion of the drum 61a.

[0053] The drum 61a supports the strainer 71, the separation plate 72, the supporting plate 73, and the partition plate 62 in order corresponding to flow of the refrigerant.

[0054] The upper end plate 61b supports the inlet pipe 63 that causes the refrigerant compressed by the compressor 2 and circulated through the refrigeration cycle apparatus 1 to flow into the accumulator 7. The inlet pipe 63 is connected to the refrigerant piping 8.

[0055] The inlet pipe 63 is fixed to the upper end plate 61b and connected to the refrigerant piping 8. The inlet pipe 63 is a straight pipe extending along a center line of the drum 61a, and is a straight pipe extending to agree with the center line of the drum 61a.

[0056] The refrigerant flowing into the accumulator 7 from the inlet pipe 63 first reaches the strainer 71. The strainer 71 has a required mesh size to prevent foreign substances from flowing into the compression mechanism 13 of the compressor 2.

[0057] The separation plate 72 prevents the refrigerant passed through the strainer 71 from directly flowing into the communication pipe 65. The separation plate 72 is a plate having a shape projecting upward that works as an umbrella for the communication pipe 65. The separation plate 72 includes a plurality of openings 72a through which the refrigerant can pass. The separation plate 72 blocks a view right below the inlet pipe 63, and blocks a view right above the communication pipe 65. The openings 72a of the separation plate 72 are placed on an outer side than a virtual minimum circle encompassing a plurality of communication pipes 65 when viewed from the inlet pipe 63. The refrigerant that has reached the separation plate 72 flows down in the refrigerant introduction chamber IR of the container 61 through the openings 72a of the separation plate 72.

[0058] Each of the openings 72a opens toward an outer peripheral side of the separation plate 72. In other words, each of the openings 72a opens toward a direction facing an inner surface of the container 61. Each of the openings 72a is formed on a plate-shaped material by lancing processing, for example. The separation plate 72 includes a plurality of deflecting plate portions 72b each having a quarter-spherical shape. The deflecting plate portions 72b are disposed on a back surface side of each of the openings 72a, that is, on a side closer to the center of the separation plate 72 than each of the openings 72a, to guide the refrigerant flowing out from each of the openings 72a toward the inner surface of the container 61 to be kept at a distance from the communication pipe 65.

[0059] The supporting plate 73 and the partition plate 62 cooperate with each other to support at least one communication pipe 65 inside the container 61. In a case in which there is a plurality of communication pipes 65, the supporting plate 73 and the partition plate 62 cooperate with each other to collectively support all of the communication pipes 65 inside the container 61.

[0060] The supporting plate 73 includes a hole that supports the communication pipe 65 and an appropriate opening that does not hinder circulation of the liquid refrigerant and the gas refrigerant so that the refrigerant introduction chamber IR becomes a continuous space. The supporting plate 73 preferably has appropriate supporting strength and supporting rigidity to prevent the communication pipe 65 extending from the partition plate 62 toward the separation plate 72 from falling down.

[0061] The partition plate 62 does not have an opening other than the hole for supporting the communication pipe 65 so that the internal space S of the container 61 is divided into the refrigerant introduction chamber IR and the refrigerant discharge chamber OR. The partition plate 62 is liquid-tightly and air-tightly joined to the inner surface of the container 61 to hinder the refrigerant from flowing out from the refrigerant introduction chamber IR to the refrigerant discharge chamber OR through a route other than the communication pipe 65. It is sufficient that the partition plate 62 includes a plane orthogonal to the center line of the container 61, and the partition plate 62 defines a plane extending in a horizontal direction in the upright state of the accumulator 7.

[0062] At least one communication pipe 65 is required. For convenience of explanation, it is assumed that the accumulator 7 according to the present embodiment includes a plurality of, for example, two communication pipes 65. The number of the communication pipes 65 is determined while considering a pressure loss, a piping diameter, and interference of an internal structure of the communication flow channel CP connecting the refrigerant introduction chamber IR with the refrigerant discharge chamber OR.

[0063] Each of the communication pipes 65 includes an inlet opening 65i disposed in the refrigerant introduction chamber IR, and an outlet opening 65o disposed in the refrigerant discharge chamber OR. The inlet opening 65i corresponds to an upstream end of the communication flow channel CP, and the outlet opening 65o corresponds to a downstream end of the communication flow channel CP.

[0064] Each of the communication pipes 65 is placed inside the container 61, and fixed to the supporting plate 73 and the partition plate 62 to connect the refrigerant introduction chamber IR with the refrigerant discharge chamber OR. Each of the communication pipes 65 is a straight pipe extending along the center line of the drum 61a, and is a straight pipe extending in parallel with the center line of the drum 61a.

[0065] A length of each of the communication pipes 65 depends on a refrigerant enclosed amount of the refrigeration cycle apparatus 1, and is preferably about a half or more of a total length of the accumulator 7.

[0066] At least one communication pipe 65 includes at least one introduction-side refrigerating machine oil return hole 65d disposed in the refrigerant introduction chamber IR. At least one introduction-side refrigerating machine oil return hole 65d is required. The introduction-side refrigerating machine oil return hole 65d may be provided on all of the communication pipes 65, or may be provided on some of the communication pipes 65. If at least one communication pipe 65 includes at least one introduction-side refrigerating machine oil return hole 65d, there may be the communication pipe 65 without the introduction-side refrigerating machine oil return hole 65d. Each of the communication pipes 65 may include a plurality of introduction-side refrigerating machine oil return holes 65d. The numbers of the introduction-side refrigerating machine oil return holes 65d included in the respective communication pipes 65 may be different from each other.

[0067] Each of the outlet pipes 66 is the suction pipe 8b of the compressor 2, and connected to corresponding one of the cylinder chambers 31 and 41 of the rotor-cylinder assemblies 26 and 27 of the compression mechanism 13. The number of the outlet pipes 66 is the same as the number of cylinders of the compressor 2. In a case of the multi-cylinder compressor 2 as illustrated in Fig. 1, the accumulator 7 is connected to the compressor 2 with the same number of outlet pipes 66 as the number of cylinders. In a case of a single-cylinder compressor 2, the accumulator 7 may be connected to the compressor 2 with one outlet pipe 66. In other words, the accumulator 7 may include at least one outlet pipe 66, and preferably includes the same number of the outlet pipes 66 as the number of cylinders of the compressor 2.

[0068] Each of the outlet pipes 66 causes the gas refrigerant separated from the refrigerant that has flowed into the accumulator 7 to flow out from the accumulator 7. Each of the outlet pipes 66 is fixed to the lower end plate 61c and connected to the compressor 2. A portion of the outlet pipe 66 inside the container 61 is a straight pipe extending along the center line of the drum 61a, and is a straight pipe extending in parallel with the center line of the drum 61a.

[0069] Each of the outlet pipes 66 includes an inlet opening 66i disposed in the refrigerant discharge chamber OR, and an outlet opening 66o connected to corresponding one of the cylinder chambers 31 and 41. The inlet opening 66i corresponds to an upstream end of the outlet flow channel OP, and the outlet opening 66o corresponds to a downstream end of the outlet flow channel OP.

[0070] At least one outlet pipe 66 includes at least one discharge-side refrigerating machine oil return hole 66d placed in the refrigerant discharge chamber OR. At least one discharge-side refrigerating machine oil return hole 66d is required. The discharge-side refrigerating machine oil return hole 66d may be provided on all of the outlet pipes 66, or may be provided on some of the outlet pipes 66. If at least one outlet pipe 66 includes at least one discharge-side refrigerating machine oil return hole 66d, there may be the outlet pipe 66 without the discharge-side refrigerating machine oil return hole 66d. Each of the outlet pipes 66 may have a plurality of discharge-side refrigerating machine oil return holes 66d. The numbers of the discharge-side refrigerating machine oil return holes 66d included in the respective outlet pipes 66 may be different from each other.

[0071] The outlet pipes 66 overlap the communication pipes 65 when viewed from a radial direction of the container 61. That is, the inlet openings 66i of the outlet pipes 66 are placed above the outlet openings 65o of the communication pipes 65. The inlet openings 66i of the outlet pipes 66 are closer to the partition plate 62 than the outlet openings 65o of the communication pipes 65. The outlet openings 65o of the communication pipes 65 are closer to the lower end plate 61c than the inlet openings 66i of the outlet pipes 66. In other words, the accumulator 7 is configured to be able to be installed on the compressor 2 while placing the inlet openings 66i of the outlet pipes 66 above the outlet openings 65o of the communication pipes 65.

[0072] The inlet openings 66i of the outlet pipes 66 face the partition plate 62 positioned above, and the outlet openings 65o of the communication pipes 65 face the lower end plate 61c positioned below.

[0073] The inlet openings 65i of the communication pipes 65 are closer to the upper end plate 61b than the partition plate 62, and the inlet openings 66i of the outlet pipes 66 are closer to the partition plate 62 than the lower end plate 61c.

[0074] The inlet openings 65i of the respective communication pipes 65 are placed at substantially the same height. In other words, the accumulator 7 is configured so that the inlet openings 65i of the communication pipes 65 can be placed at substantially the same height. The inlet openings 66i of the respective outlet pipes 66 are placed at substantially the same height. In other words, the accumulator 7 is configured so that the inlet openings 66i of the outlet pipes 66 can be placed at substantially the same height. When the inlet openings 65i of the communication pipes 65 are placed at substantially the same height, the inlet openings 66i of the outlet pipes 66 are placed at substantially the same height.

[0075] The container 61 is an assembly of three members that are divided in a middle of the drum 61a on the side of the upper end plate 61b and a middle of the drum 61a on the side of the lower end plate 61c to be air-tightly joined to each other. It is preferable that the inlet pipe 63, the strainer 71, and the separation plate 72 are incorporated in a member on the upper side before assembling the container 61, the outlet pipe 66 is incorporated in a member on the lower side before assembling the container 61, and the partition plate 62, the supporting plate 73, and the communication pipe 65 are incorporated in a center member before assembling the container 61. The supporting plate 73 may be disposed on a division surface between the member on the upper side and the center member, or may be fixed to an inner side of the center member.

[0076] The container 61 may also be an assembly of two members that are divided in the middle of the drum 61a to be air-tightly joined to each other. It is preferable that the inlet pipe 63, the strainer 71, and the separation plate 72 are incorporated in a member on the upper side before assembling the container 61, and the outlet pipe 66, the partition plate 62, the supporting plate 73, and the communication pipe 65 are incorporated in a member on the lower side before assembling the container 61. The supporting plate 73 may be disposed on a division surface between the two members, or may be fixed to an inner side of the member on the lower side.

[0077] Fig. 4 is a horizontal cross-sectional view of the accumulator according to the embodiment of the present invention.

[0078] Fig. 4 illustrates a cross section with which an arrangement relation among the container 61 of the accumulator 7, the communication pipes 65, and the outlet pipes 66 can be grasped, for example, a cross-sectional view along a line IV-IV in Fig. 2 and Fig. 3.

[0079] As illustrated in Fig. 4, the inlet openings 66i of the outlet pipes 66 of the accumulator 7 according to the present embodiment are arranged not to overlap the outlet openings 65o of the communication pipes 65 in a vertical direction. In other words, the accumulator 7 is configured to be able to be installed so that the inlet openings 66i of the outlet pipes 66 do not overlap the outlet openings 65o of the communication pipes 65 in the vertical direction.

[0080] The accumulator 7 according to the present embodiment includes the two outlet pipes 66 corresponding to the two-cylinder compressor 2, and the two communication pipes 65 connecting the refrigerant introduction chamber IR with the refrigerant discharge chamber OR. The two outlet pipes 66 and the two communication pipes 65 are alternately arranged in a circumferential direction of the container 61. Due to such arrangement, the communication pipes 65 and the outlet pipes 66 are arranged to overlap each other when viewed from the radial direction of the container 61. Such an arrangement relation among the communication pipes 65 and the outlet pipes 66 prevents, even if a liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet opening 65i of any of the communication pipes 65 and the liquid refrigerant falls down in the communication flow channel CP of any of the communication pipes 65, the liquid refrigerant flowing out from the communication flow channel CP to the refrigerant discharge chamber OR from directly flowing out from the inlet opening 66i of the outlet pipe 66 to the outlet flow channel OP.

[0081] In the accumulator 7 configured as described above, the refrigerant falling down from the inlet pipe 63 to the refrigerant introduction chamber IR in the container 61 hits the separation plate 72, and is separated into a gas refrigerant and a liquid refrigerant. The separated liquid refrigerant further flows down from the opening 72a of the separation plate 72 in the refrigerant introduction chamber IR, and is accumulated on a bottom of the refrigerant introduction chamber IR, that is, on the side of the partition plate 62. On the other hand, the separated gas refrigerant flows into the refrigerant discharge chamber OR through the communication pipes 65 from the opening 72a of the separation plate 72. The gas refrigerant that has flowed into the refrigerant discharge chamber OR is sucked into the outlet pipe 66, and sent to the compressor 2.

[0082] Unless the liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet openings 65i of the communication pipes 65, the accumulator 7 does not cause the liquid refrigerant to flow into the refrigerant discharge chamber OR. If the liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet openings 65i of the communication pipes 65, the liquid refrigerant falls down in the communication pipe 65, and is accumulated on a bottom of the container 61, that is, on the side of the lower end plate 61c. Also in this case, unless the liquid level of the liquid refrigerant accumulated in the refrigerant discharge chamber OR reaches the inlet openings 66i of the outlet pipes 66, the accumulator 7 does not cause the liquid refrigerant to flow into the outlet pipe 66. In this way, the accumulator 7 can prevent liquid compression in the compressor 2 in multiple ways.

[0083] The refrigerating machine oil in the sealed container 11 of the compressor 2 circulates in the refrigeration cycle apparatus 1 together with the refrigerant. In the accumulator 7, the refrigerating machine oil flowing from the inlet pipe 63 into the refrigerant introduction chamber IR in the container 61 together with the refrigerant hits the separation plate 72, further falls down from the opening 72a of the separation plate 72 in the refrigerant introduction chamber IR, and is accumulated on the bottom of the refrigerant introduction chamber IR, that is, on the side of the partition plate 62. A specific gravity of the refrigerating machine oil is larger than a specific gravity of the refrigerant, and the refrigerating machine oil is accumulated to be closer to the bottom side of the refrigerant introduction chamber IR than the refrigerant. When the liquid level of the refrigerating machine oil accumulated in the refrigerant introduction chamber IR reaches the introduction-side refrigerating machine oil return hole 65d closest to the partition plate 62, the accumulator 7 causes the refrigerating machine oil to flow out from the refrigerant introduction chamber IR to the refrigerant discharge chamber OR through the communication pipe 65. The refrigerating machine oil flowed out to the refrigerant discharge chamber OR is accumulated on the bottom of the container 61, that is, on a bottom of the lower end plate 61c. When the liquid level of the refrigerating machine oil accumulated in the refrigerant discharge chamber OR reaches the discharge-side refrigerating machine oil return hole 66d closest to the lower end plate 61c, the accumulator 7 causes the refrigerating machine oil to flow out from the refrigerant discharge chamber OR to the compressor 2 through the outlet pipe 66.

[0084] However, similarly to the fact that it is not preferable that the liquid refrigerant flows out from the accumulator 7 to the compressor 2, it is not preferable that the liquid level of the refrigerating machine oil accumulated in the refrigerant discharge chamber OR reaches the inlet opening 66i of the outlet pipe 66, and the refrigerating machine oil excessively overflows to the compressor 2.

[0085] Thus, oil returning capability of the discharge-side refrigerating machine oil return hole 66d of the accumulator 7 according to the present embodiment is set to be higher than oil returning capability of the introduction-side refrigerating machine oil return hole 65d. Specifically, a pressure loss of the discharge-side refrigerating machine oil return hole 66d is set to be smaller and lower than a pressure loss of the introduction-side refrigerating machine oil return hole 65d. That is, the refrigerating machine oil can be rapidly discharged through a downstream-side route for causing the refrigerating machine oil accumulated in the refrigerant discharge chamber OR to flow out to the compressor 2 through the discharge-side refrigerating machine oil return hole 66d rather than an upstream-side route for causing the refrigerating machine oil accumulated in the refrigerant introduction chamber IR to flow out to the refrigerant discharge chamber OR through the introduction-side refrigerating machine oil return hole 65d. Thus, in the accumulator 7, the refrigerating machine oil tends to be accumulated in the refrigerant introduction chamber IR rather than the refrigerant discharge chamber OR. Due to such a relation among discharge routes for the refrigerating machine oil, even if the liquid level of the refrigerating machine oil accumulated in the refrigerant introduction chamber IR reaches the inlet opening 65i of any of the communication pipes 65 and the refrigerating machine oil falls down in the communication flow channel CP of any of the communication pipes 65, the refrigerating machine oil flowing out from the communication flow channel CP to the refrigerant discharge chamber OR is prevented from directly flowing out from the inlet opening 66i of the outlet pipe 66 to the outlet flow channel OP.

[0086] The following describes a sum total ΣAcd of opening areas of the introduction-side refrigerating machine oil return holes 65d, and a sum total ΣAod of opening areas of the discharge-side refrigerating machine oil return holes 66d.

[0087] The sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d is obtained by adding up opening areas Acd of the respective introduction-side refrigerating machine oil return holes 65d. The opening areas Acd of the introduction-side refrigerating machine oil return holes 65d may be the same, or may be different from each other. In other words, the introduction-side refrigerating machine oil return holes 65d may have the same opening diameter, or may have different opening diameters. In a case in which a desired sum total ΣAcd of the opening areas can be obtained by combining the introduction-side refrigerating machine oil return holes 65d having the same opening diameter, the introduction-side refrigerating machine oil return holes 65d may have the same opening diameter. In a case in which a desired sum total ΣAcd of the opening areas can be obtained by combining the introduction-side refrigerating machine oil return holes 65d having different opening diameters, the introduction-side refrigerating machine oil return holes 65d may have different opening diameters. In a case in which the accumulator 7 includes only one introduction-side refrigerating machine oil return hole 65d, the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d is the opening area Acd of the one introduction-side refrigerating machine oil return hole 65d.

[0088] The sum total ΣAod of the opening area of the discharge-side refrigerating machine oil return holes 66d is obtained by adding up opening areas Aod of the respective discharge-side refrigerating machine oil return holes 66d. The opening areas Aod of the discharge-side refrigerating machine oil return holes 66d may be the same, or may be different from each other. In other words, the discharge-side refrigerating machine oil return holes 66d may have the same opening diameter, or may have different opening diameters. In a case in which a desired sum total ΣAod of the opening areas can be obtained by combining the discharge-side refrigerating machine oil return holes 66d having the same opening diameter, the discharge-side refrigerating machine oil return holes 66d may have the same opening diameter. In a case in which a desired sum total ΣAod of the opening areas can be obtained by combining the discharge-side refrigerating machine oil return holes 66d having different opening diameters, the discharge-side refrigerating machine oil return holes 66d may have different opening diameters. In a case in which the accumulator 7 includes only one discharge-side refrigerating machine oil return hole 66d, the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d is the opening area Aod of the one discharge-side refrigerating machine oil return hole 66d.

[0089] The following also describes a sum total ΣAip of a cross-sectional area of the inlet flow channel IP, a sum total ΣAcp of cross-sectional areas of communication flow channels CP, and a sum total ΣAop of cross-sectional areas of outlet flow channels OP.

[0090] The sum total ΣAip of the cross-sectional area of the inlet flow channel IP is substantially equal to the cross-sectional area Aip of the one inlet pipe 63.

[0091] The sum total ΣAcp of the cross-sectional areas of the communication flow channels CP is obtained by adding up cross-sectional areas Acp of the respective communication pipes 65. The cross-sectional areas Acp of the communication pipes 65 may be the same, or may be different from each other. In other words, the communication pipes 65 may be a plurality of pipes having the same inner diameter, or may be a plurality of pipes having different inner diameters. In a case in which a desired sum total ΣAcp of the cross-sectional areas can be obtained by combining pipes having the same inner diameter, the communication pipes 65 may have the same inner diameter. In a case in which a desired sum total ΣAcp of the cross-sectional areas can be obtained by combining pipes having different inner diameters, the communication pipes 65 may have different inner diameters. In a case in which the accumulator 7 includes only one communication pipe 65, the sum total ΣAcp of the cross-sectional area of the communication pipes 65 is the cross-sectional area Acp of the one communication pipe 65.

[0092] The sum total ΣAop of the cross-sectional areas of the outlet flow channels OP is obtained by adding up cross-sectional areas Aop of the respective outlet pipes 66. The cross-sectional areas Aop of the outlet pipes 66 may be the same, or may be different from each other. In other words, the outlet pipes 66 may be a plurality of pipes having the same inner diameter, or may be a plurality of pipes having different inner diameters. The cross-sectional area Aop of each of the outlet pipes 66 depends on effective capacity of corresponding one of the rotor-cylinder assemblies 26 and 27. In a case in which the accumulator 7 includes only one outlet pipe 66, the sum total ΣAop of the cross-sectional areas of the outlet pipes 66 is the cross-sectional area Aop of the one outlet pipe 66.

[0093] To cause the pressure loss of the discharge-side refrigerating machine oil return hole 66d to be smaller and lower than the pressure loss of the introduction-side refrigerating machine oil return hole 65d, for example, the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP is larger than the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP, a distance Lc from the inlet opening 65i of the communication pipe 65 to the introduction-side refrigerating machine oil return hole 65d is longer than a distance Lo from the inlet opening 66i of the outlet pipe 66 to the discharge-side refrigerating machine oil return hole 66d, and the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d is equal to or larger than the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d.

[0094] That is, when (the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d) ≤ (the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d), and (the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP) < (the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP), and (the distance Lo) < (the distance Lc) are satisfied, a relative difference in the pressure loss is caused between the oil return holes 65d and 66d, and the oil returning capability of the discharge-side refrigerating machine oil return hole 66d becomes higher than the oil returning capability of the introduction-side refrigerating machine oil return hole 65d.

[0095] Alternatively, the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d may be the same as the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d. In this case, by setting (the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d) = (the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d), and (the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP) < (the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP), a flow speed in the outlet pipe 66 becomes higher than that in the communication pipe 65, and a relative difference in the pressure loss is caused between the discharge-side refrigerating machine oil return hole 66d and the introduction-side refrigerating machine oil return hole 65d, so that the oil returning capability of the discharge-side refrigerating machine oil return hole 66d becomes higher than the oil returning capability of the introduction-side refrigerating machine oil return hole 65d.

[0096] By setting (the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d) < (the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d), and (the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP) ≤ (the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP) or (the distance Lo) ≤ (the distance Lc), a difference in the pressure loss is caused due to a difference between the opening areas of the respective oil return holes 65d and 66d, and the oil returning capability of the discharge-side refrigerating machine oil return hole 66d becomes higher than that of the introduction-side refrigerating machine oil return hole 65d.

[0097] In a case of providing a plurality of the discharge-side refrigerating machine oil return holes 66d and the introduction-side refrigerating machine oil return holes 65d, a larger number of the discharge-side refrigerating machine oil return holes 66d than the introduction-side refrigerating machine oil return holes 65d may be provided so that the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d is equal to or larger than the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d. For example, in a case of providing the discharge-side refrigerating machine oil return holes 66d and the introduction-side refrigerating machine oil return holes 65d by drills having the same drill diameter, a large number of the discharge-side refrigerating machine oil return holes 66d may be drilled on the outlet pipe 66, and a small number of the introduction-side refrigerating machine oil return holes 65d may be drilled on the communication pipe 65. In other words, the number of the discharge-side refrigerating machine oil return holes 66d may be larger than the number of the introduction-side refrigerating machine oil return holes 65d.

[0098] On the other hand, in a case in which the number of the discharge-side refrigerating machine oil return holes 66d is the same as the number of the introduction-side refrigerating machine oil return holes 65d, for example, when the number thereof is one, the opening diameter of the discharge-side refrigerating machine oil return hole 66d may be larger than the opening diameter of the introduction-side refrigerating machine oil return hole 65d.

[0099] The discharge-side refrigerating machine oil return holes 66d are preferably placed at the same distance Lo from the inlet opening 66i of the outlet pipe 66. Additionally, the introduction-side refrigerating machine oil return holes 65d are preferably placed at the same distance Lc from the inlet opening 65i of the communication pipe 65. That is, the discharge-side refrigerating machine oil return holes 66d are preferably arranged in a ring shape in a circumferential direction of the outlet pipe 66. The introduction-side refrigerating machine oil return holes 65d are preferably arranged in a ring shape in a circumferential direction of the communication pipe 65. For example, in a case of drilling two introduction-side refrigerating machine oil return holes 65d on the communication pipe 65, the drill may be moved orthogonally to a center line of the communication pipe 65 to pass through the communication pipe 65. In a case of drilling four discharge-side refrigerating machine oil return holes 66d on the outlet pipe 66, the drill may be moved orthogonally to the center line of the outlet pipe 66 to pass through the outlet pipe 66 twice. The oil return holes 65d and 66d may be arranged in a ring shape at regular intervals or at irregular intervals.

[0100] In design of the rotary compressor, a high load condition with a large circulation amount of the refrigerant in a refrigerating cycle is extremely important in designing a theoretical suction volume, a maximum rotation speed, and a motor capacity. A practical use of the supercharging effect is effective for designing the rotary compressor. The supercharging effect increases the circulation amount of the refrigerant at a specific rotation speed due to columnar resonance of a suction piping system of the compressor.

[0101] Fig. 5 is a diagram for comparing the accumulator according to the present embodiment with a conventional accumulator in the supercharging effect.

[0102] In Fig. 5, a horizontal axis indicates an operation frequency (hertz, Hz, 1 / second) of the crank shaft 15 of the compressor 2, and a vertical axis indicates a normalized value obtained by dividing volumetric efficiency at each operation frequency by a maximum value of the volumetric efficiency in a case of changing the operation frequency of the compressor 2 from 30 hertz to 120 hertz.

[0103] A conventional accumulator as a comparative example in Fig. 5 does not include the communication pipe 65 and the partition plate 62 of the accumulator 7 according to the present embodiment, but includes the outlet pipe 66 and the supporting plate 73 supporting the outlet pipe 66, the outlet pipe 66 projecting from the lower end plate 61c to the internal space S of the container 61 to extend to a vicinity of the separation plate 72, and having the inlet opening 66i facing the separation plate 72. In this conventional accumulator 7, a length of a straight pipe portion of the outlet pipe 66 inside the container 61 is assumed to be 0.35 times the length of the straight pipe portion of the outlet pipe 66 inside the container 61 according to the present embodiment.

[0104] When the accumulators are connected to completely the same compressor 2, the volumetric efficiency of the conventional accumulator indicated by a dashed line α takes a maximum value at an operation frequency of 85 hertz, and the volumetric efficiency of the accumulator 7 according to the present embodiment indicated by a solid line β takes a maximum value at an operation frequency of 110 hertz. That is, the accumulator 7 according to the present embodiment exhibits the supercharging effect at a higher frequency than the conventional accumulator 7. The accumulator 7 has an extremely high degree of freedom in design corresponding to a characteristic of the compressor 2 such that a piping length of the suction piping system of the compressor 2 including the outlet pipe 66 and the communication pipe 65 can be easily adjusted to be a piping length required for the supercharging effect.

[0105] The sum total ΣAip of the cross-sectional area of the inlet flow channel IP is preferably larger than the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP. This large / small relation between the cross-sectional areas of the flow channels promotes accumulation and retention of the liquid refrigerant in the accumulator 7, and accelerates separation of the liquid refrigerant and the gas refrigerant.

[0106] The sum total ΣAcp of the cross-sectional areas of the communication flow channels CP is preferably equal to or larger than the sum total ΣAip of the cross-sectional area of the inlet flow channel IP. This large / small relation between the cross-sectional areas of the flow channels contributes to causing the gas refrigerant separated in the refrigerant introduction chamber IR to quickly flow out to the refrigerant discharge chamber OR.

[0107] Fig. 6 is a diagram illustrating a relation between the cross-sectional area of the communication flow channel and the cross-sectional area of the outlet flow channel of the accumulator according to the present embodiment.

[0108] In Fig. 6, a horizontal axis indicates an area ratio AR obtained by dividing the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP by the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP, and a vertical axis indicates volumetric efficiency of the compressor 2 at the same operation frequency.

[0109] Herein, (the area ratio AR) = (the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP) ÷ (the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP) is satisfied. That is, the area ratio AR is magnification or ratio of the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP with respect to the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP.

[0110] As illustrated in Fig. 6, the volumetric efficiency of the compressor 2 is abruptly increased when the area ratio AR is smaller than 1.2, and the volumetric efficiency of the compressor 2 converges in a state of being sufficiently increased when the area ratio AR is equal to or larger than 1.2. Thus, the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP is preferably 1.2 times or more the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP. To set the oil returning capability of the discharge-side refrigerating machine oil return hole 66d to be higher than the oil returning capability of the introduction-side refrigerating machine oil return hole 65d, the area ratio AR may be larger than 1.0.

[0111] Thus, from a viewpoint of the volumetric efficiency of the compressor 2, the sum total ΣAcp of the cross-sectional areas Acp of the communication flow channels CP is preferably equal to or larger than the sum total ΣAip of the cross-sectional area Aip of the inlet flow channel IP and 1.2 times or more the sum total ΣAop of the cross-sectional areas Aop of the outlet flow channels OP. The large / small relation among the cross-sectional areas is preferably established even in a case in which the numbers of the inlet pipe 63, the communication pipe 65, and the outlet pipe 66 are all one.

[0112] As illustrated in Fig. 6, the volumetric efficiency of the compressor 2 is lowered when the area ratio AR exceeds a predetermined value. Specifically, the volumetric efficiency of the compressor 2 tends to be lowered when the area ratio AR exceeds 1.30, and the volumetric efficiency of the compressor 2 becomes lower than the volumetric efficiency of the compressor 2 at the area ratio of 1.2 when the area ratio AR exceeds 1.6.

[0113] Furthermore, when the area ratio AR is excessively increased, that is, when the communication flow channel CP is excessively enlarged, a ratio of the communication flow channel CP occupying the internal space S of the accumulator 7 is increased, and a storage amount of the liquid refrigerant in the refrigerant introduction chamber IR and the refrigerant discharge chamber OR is consumed. Due to this, the area ratio AR is preferably equal to or smaller than 1.6.

[0114] Typically, capacity and an inner diameter dimension of the accumulator 7 attached to the compressor 2 are appropriately changed in accordance with operation capacity of the compressor 2. For example, the inner diameter dimension of the accumulator 7 is about three times to six times an outer diameter dimension of the outlet pipe 66. The inner diameter dimension of the accumulator 7 according to the present embodiment is about five times the outer dimension of the outlet pipe 66. The inlet opening 65i of the communication pipe 65 is placed not to be opposed to a plurality of the openings 72a provided on the separation plate 72. This prevents the refrigerant circulating through the openings 72a of the separation plate 72 from being directly supplied to the inlet opening 65i of the communication pipe 65.

[0115] Lower end portions of the communication pipes 65 and upper end portions of the outlet pipes 66 overlap each other in the refrigerant discharge chamber OR in the vertical direction. The sum total ΣAcp of the cross-sectional areas of the communication flow channels CP may take a maximum value in a range in which the opening 72a of the separation plate 72 is placed outside a virtual minimum circle encompassing the communication pipes 65 when viewed from the inlet pipe 63. In a case of such an arrangement relation between the communication pipe 65 and the outlet pipe 66, by setting the area ratio AR to be equal to or smaller than 1.6 times, the accumulator 7 can be prevented from being upsized without reducing the storage amount of the liquid refrigerant in the refrigerant introduction chamber IR while maintaining high volumetric efficiency of the compressor 2.

[0116] Next, the following describes another aspect of the accumulator 7 according to the present embodiment. Regarding an accumulator 7A of the another aspect described below, the same configuration as that of the accumulator 7 described above with reference to Fig. 1 to Fig. 6 is denoted by the same reference numeral, and redundant description will not be repeated.

[0117] Fig. 7 is a vertical cross-sectional view of another aspect of the accumulator according to the embodiment of the present invention.

[0118] As illustrated in Fig. 7, the accumulator 7A according to a second aspect according to the present embodiment includes at least one second discharge-side refrigerating machine oil return hole 66d2. The second discharge-side refrigerating machine oil return hole 66d2 is placed to be closer to the inlet opening 66i of the outlet pipe 66 than the discharge-side refrigerating machine oil return hole 66d. The second discharge-side refrigerating machine oil return hole 66d2 may be placed in a region in which the communication pipe 65 overlaps the outlet pipe 66 when viewed from the radial direction of the container 61, or may be placed in a region in which the communication pipe 65 does not overlap the outlet pipe 66 when viewed from the radial direction of the container 61. That is, the accumulator 7A can be installed so that the second discharge-side refrigerating machine oil return hole 66d2 is placed below the outlet opening 65o of the communication pipe 65, or can be installed so that the second discharge-side refrigerating machine oil return hole 66d2 is placed above the outlet opening 65o of the communication pipe 65.

[0119] In a case in which there is a plurality of second discharge-side refrigerating machine oil return holes 66d2, the second discharge-side refrigerating machine oil return holes 66d2 may be arranged in the circumferential direction of the outlet pipe 66, or may be arranged in an extending direction of the outlet pipe 66. The second discharge-side refrigerating machine oil return holes 66d2 may be disposed on a certain outlet pipe 66 in a concentrated manner, or may be disposed on a plurality of outlet pipes 66 in a dispersed manner.

[0120] The second discharge-side refrigerating machine oil return holes 66d2 preferably have opening areas equal to or larger than that of the discharge-side refrigerating machine oil return hole 66d. The second discharge-side refrigerating machine oil return holes 66d2 arranged in the extending direction of the outlet pipe 66 may all have the same opening area, or may include a hole having a different opening area. In a case of providing the second discharge-side refrigerating machine oil return holes 66d2 having different opening areas, it is preferable that the second discharge-side refrigerating machine oil return hole 66d2 closer to the inlet opening 66i of the outlet pipe 66 has a larger opening area. In other words, among the second discharge-side refrigerating machine oil return holes 66d2 arranged in the extending direction of the outlet pipe 66, the hole more distant from the discharge-side refrigerating machine oil return hole 66d preferably has a larger opening area. The opening areas of the second discharge-side refrigerating machine oil return holes 66d2 may be set based on an opening diameter of each of the second discharge-side refrigerating machine oil return holes 66d2 or the number of the second discharge-side refrigerating machine oil return holes 66d2.

[0121] In a case in which the liquid level of the refrigerating machine oil accumulated in the refrigerant discharge chamber OR falls within an appropriate range, the accumulator 7A returns an appropriate amount of refrigerating machine oil to the compressor 2 through the discharge-side refrigerating machine oil return hole 66d. On the other hand, in a case in which an amount of the flowing-in refrigerating machine oil exceeds discharge capacity of the discharge-side refrigerating machine oil return hole 66d, and the refrigerating machine oil is excessively accumulated in the refrigerant discharge chamber OR, the accumulator 7A returns the refrigerating machine oil to the compressor 2 through the second discharge-side refrigerating machine oil return hole 66d2 in addition to the discharge-side refrigerating machine oil return hole 66d. In this way, the accumulator 7A can prevent the refrigerating machine oil from overflowing from the inlet opening 66i of the outlet pipe 66.

[0122] In a case in which the second discharge-side refrigerating machine oil return hole 66d2 closer to the inlet opening 66i of the outlet pipe 66 has a larger opening area, as the liquid level of the refrigerating machine oil in the refrigerant discharge chamber OR becomes higher, a total of the discharge capacity of the discharge-side refrigerating machine oil return hole 66d and the second discharge-side refrigerating machine oil return hole 66d2 rapidly and nonlinearly increases. Thus, the accumulator 7A can more securely prevent the refrigerating machine oil from overflowing from the inlet opening 66i of the outlet pipe 66.

[0123] The second discharge-side refrigerating machine oil return hole 66d2 may be a continuous slit-like hole extending in the extending direction of the outlet pipe 66. The slit-like second discharge-side refrigerating machine oil return hole 66d2 enhances oil returning capability following rise of the liquid level of the refrigerating machine oil similarly to the circular-shaped second discharge-side refrigerating machine oil return holes 66d2.

[0124] As described above, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments include the discharge-side refrigerating machine oil return hole 66d having oil returning capability higher than that of the introduction-side refrigerating machine oil return hole 65d. At least one introduction-side refrigerating machine oil return hole 65d and at least one discharge-side refrigerating machine oil return hole 66d are required. That is, the accumulators 7 and 7A according to the present embodiment include at least one discharge-side refrigerating machine oil return hole 66d having higher oil returning capability than that of at least one introduction-side refrigerating machine oil return hole 65d. Thus, even if the liquid level of the refrigerating machine oil accumulated in the refrigerant introduction chamber IR reaches the inlet opening 65i of any of the communication pipes 65, and the refrigerating machine oil flows down in the communication flow channel CP of any of the communication pipe 65, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 prevent the refrigerating machine oil flowing out from the communication flow channel CP to the refrigerant discharge chamber OR from directly flowing out from the inlet opening 66i of the outlet pipe 66 to the outlet flow channel OP.

[0125] In the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments, the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP is larger than the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP, the distance Lc from the inlet opening 65i of the communication pipe 65 to the introduction-side refrigerating machine oil return hole 65d is longer than the distance Lo from the inlet opening 66i of the outlet pipe 66 to the discharge-side refrigerating machine oil return hole 66d, and the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d is equal to or larger than the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d. At least one communication pipe 65, at least one outlet pipe 66, at least one introduction-side refrigerating machine oil return hole 65d, and at least one discharge-side refrigerating machine oil return hole 66d are required. That is, the sum total ΣAcp of the cross-sectional areas of the communication flow channels CP is larger than the sum total ΣAop of the cross-sectional areas of the outlet flow channels OP, the distance Lc from the inlet opening 65i of at least one communication pipe 65 to at least one introduction-side refrigerating machine oil return hole 65d is longer than the distance Lo from the inlet opening 66i of at least one outlet pipe 66 to at least one discharge-side refrigerating machine oil return hole 66d, and the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d is equal to or larger than the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d. Thus, with the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1, a pressure loss of the downstream-side route for causing the refrigerating machine oil to flow out from the refrigerant discharge chamber OR to the compressor 2 can be easily set to be smaller than a pressure loss of the upstream-side route for causing the refrigerating machine oil to flow out from the refrigerant introduction chamber IR to the refrigerant discharge chamber OR.

[0126] Furthermore, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments include a plurality of the introduction-side refrigerating machine oil return holes 65d and a plurality of the discharge-side refrigerating machine oil return holes 66d, and the number of the discharge-side refrigerating machine oil return holes 66d is larger than the number of the introduction-side refrigerating machine oil return holes 65d. Thus, in the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1, the discharge-side refrigerating machine oil return holes 66d and the introduction-side refrigerating machine oil return holes 65d can be provided in common by drills having the same drill diameter, for example, and the sum total ΣAod of the opening areas of the discharge-side refrigerating machine oil return holes 66d can be easily set to be equal to or larger than the sum total ΣAcd of the opening areas of the introduction-side refrigerating machine oil return holes 65d.

[0127] The accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments also include a plurality of the discharge-side refrigerating machine oil return holes 66d arranged in the extending direction of at least one outlet pipe 66. Thus, when the liquid level of the refrigerating machine oil accumulated in the refrigerant discharge chamber OR rises, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 enhance oil returning capability of the downstream-side route for causing the refrigerating machine oil to flow out from the refrigerant discharge chamber OR to the compressor 2 accordingly, and can more securely prevent the refrigerating machine oil from overflowing from the inlet opening 66i of the outlet pipe 66.

[0128] Furthermore, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments include a plurality of the discharge-side refrigerating machine oil return holes 66d each having an opening area that is increased as being closer to the inlet opening 66i of at least one outlet pipe 66. Thus, when the liquid level of the refrigerating machine oil accumulated in the refrigerant discharge chamber OR rises, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 abruptly increase oil returning capability of the downstream-side route for causing the refrigerating machine oil to flow out from the refrigerant discharge chamber OR to the compressor 2 accordingly, and can further securely prevent the refrigerating machine oil from overflowing from the inlet opening 66i of the outlet pipe 66.

[0129] The accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments can be installed so that the inlet opening 66i of at least one outlet pipe 66 is placed above the outlet opening 65o of at least one communication pipe 65, and the inlet opening 66i of at least one outlet pipe 66 does not overlap the outlet opening 65o of at least one communication pipe 65 in the vertical direction. The compressor 2 and the refrigeration cycle apparatus 1 according to the present embodiments include the accumulators 7 and 7A that are installed so that the inlet opening 66i of at least one outlet pipe 66 is placed above the outlet opening 65o of at least one communication pipe 65, and the inlet opening 66i of at least one outlet pipe 66 does not overlap the outlet opening 65o of at least one communication pipe 65 in the vertical direction. Thus, even if the liquid refrigerant is returned to the accumulator 7, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 can accumulate the liquid refrigerant in the refrigerant introduction chamber IR and the refrigerant discharge chamber OR inside the accumulators 7 and 7A in a multistage manner. In this way, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 can prevent the liquid refrigerant from easily flowing out from at least one outlet pipe 66, and can further prevent liquid compression in the compressor 2. The accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 can easily achieve both of prevention of liquid compression in the compressor 2, and a practical use of the supercharging effect by adjusting the piping length of the suction piping system of the compressor 2 including the outlet pipe 66 and the communication pipe 65 as illustrated in Fig. 5.

[0130] The accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments also include the inlet opening 66i of the outlet pipe 66 facing the partition plate 62 positioned above and the outlet opening 65o of the communication pipe 65 facing the lower end plate 61c positioned below. The portion of the outlet pipe 66 inside the container 61, the inlet pipe 63, and the communication pipe 65 are straight pipes extending in parallel with the center line of the drum 61a of the container 61. Thus, the vertical-type accumulators 7 and 7A, the vertical-type compressor 2, and the refrigeration cycle apparatus 1 including them can easily achieve both of prevention of liquid compression in the compressor 2 and a practical use of the supercharging effect.

[0131] Furthermore, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments include the inlet opening 66i of the outlet pipe 66 closer to the partition plate 62 than the lower end plate 61c. Thus, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 secure a storage amount of the liquid refrigerant in the refrigerant discharge chamber OR. Maximization of the storage amount of the liquid refrigerant in the refrigerant discharge chamber OR prevents, even if the liquid refrigerant overflows from the refrigerant introduction chamber IR to the communication pipe 65, the liquid refrigerant flowing out from the communication pipe 65 to the refrigerant discharge chamber OR from immediately flowing out to the compressor 2.

[0132] The accumulators 7 and 7A according to the present embodiment also include a plurality of the communication pipes 65 whose inlet openings 65i can be placed at substantially the same height. The compressor 2 and the refrigeration cycle apparatus 1 according to the present embodiments include a plurality of the communication pipes 65 whose inlet openings 65i are placed at substantially the same height. Thus, while securing the flow channel cross-sectional area of the communication flow channel CP, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 can easily set an arrangement relation between the communication pipe 65 and the outlet pipe 66 so that the outlet opening 65o of the communication pipe 65 does not overlap the inlet opening 66i of the outlet pipe 66 in the upper and lower direction in which the liquid refrigerant flows down. That is, even if the liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet opening 65i of any of the communication pipes 65 and the liquid refrigerant flows down in the communication flow channel CP of any of the communication pipes 65, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 prevent the liquid refrigerant flowing out from the communication flow channel CP to the refrigerant discharge chamber OR from directly flowing out from the inlet opening 66i of the outlet pipe 66 to the outlet flow channel OP. The communication pipes 65 can easily adjust a total pressure loss of a plurality of the communication flow channels CP by causing the communication flow channels CP to be individually different from each other or to be the same.

[0133] Furthermore, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments include a plurality of the outlet pipes 66. Thus, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 can easily cope with the multi-cylinder compressor 2.

[0134] The accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments preferably include at least one communication pipe 65 in which the sum total ΣAcp of the cross-sectional areas Acp is equal to or larger than the sum total ΣAip of the cross-sectional area Aip of the inlet flow channel IP and 1.2 times or more the sum total ΣAop of the cross-sectional areas Aop of the outlet flow channels OP. In this case, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 improve gas-liquid separation capacity of the accumulators 7 and 7A and accelerate a practical use of the supercharging effect without hindering flow of the refrigerant in the accumulators 7 and 7A due to a pressure loss of at least one communication pipe 65 connecting the refrigerant introduction chamber IR with the refrigerant discharge chamber OR.

[0135] Furthermore, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments include the inlet pipe 63 in which the sum total ΣAip of the cross-sectional area Aip is larger than the sum total ΣAop of the cross-sectional areas Aop of the outlet flow channels OP. Thus, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 promote accumulation and retention of the liquid refrigerant in the accumulators 7 and 7A, and accelerate separation of the liquid refrigerant and the gas refrigerant.

[0136] Thus, the accumulators 7 and 7A, the compressor 2, and the refrigeration cycle apparatus 1 according to the present embodiments can achieve both of gas-liquid separation capacity that can securely prevent the liquid refrigerant from flowing out, in other words, gas-liquid separation capacity that can securely prevent liquid compression in the compressor 2, and adjustment of the oil return flow rate for returning the caught refrigerating machine oil to the compressor 2 at an appropriate flow rate.

[0137] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions, and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.REFERENCE SIGNS LIST

[0138] 1... refrigeration cycle apparatus, 2... rotary compressor (compressor), 3... radiator, 5... expansion device, 6... heat absorber, 7, 7A... accumulator, 8... refrigerant piping, 8a... discharge pipe, 8b... suction pipe, 11... sealed container, 11a... drum, 11b... upper end plate, 11c... lower end plate, 12... electric motor, 13... compression mechanism, 14... frame, 15... crank shaft, 15a... intermediate portion, 15b... lower end portion, 16... main bearing, 17... auxiliary bearing, 18... sealed terminal portion, 21... stator, 22... rotor, 23... lead wire, 25... eccentric portion, 25a... first eccentric portion, 25b... second eccentric portion, 26... first rotor-cylinder assembly, 27... second rotor-cylinder assembly, 29... partition plate, 31... first cylinder chamber, 32... first cylinder, 33... first rolling piston (first piston), 41... second cylinder chamber, 42... second cylinder, 43... second rolling piston (second piston), 45... vane, 51, 52, 58... bolt, 55... first discharge muffler, 57... second discharge muffler, 59... clamp band, 61... container, 61a... drum, 61b... upper end plate, 61c... lower end plate, 62... partition plate, 63... inlet pipe, 65... communication pipe, 65i... inlet opening, 65o... outlet opening, 65d... introduction-side refrigerating machine oil return hole, 66... outlet pipe, 66i... inlet opening, 66o... outlet opening, 66d... discharge-side refrigerating machine oil return hole, 66d2... second discharge-side refrigerating machine oil return hole, 71... strainer, 72... separation plate, 72a... opening, 72b... deflecting plate portion, 73... supporting plate.

Claims

1. An accumulator (7) comprising: a container (61); a partition plate (62) that is disposed inside the container (61), and divides an internal space (S) of the container (61) into a refrigerant introduction chamber (IR) and a refrigerant discharge chamber (OR); an inlet pipe (63) that is fixed to the container (61) and includes an inlet flow channel (IP) connected to the refrigerant introduction chamber (IR); at least one communication pipe (65) including a communication flow channel (CP) that passes through the partition plate (62) to connect the refrigerant introduction chamber (IR) with the refrigerant discharge chamber (OR); and at least one outlet pipe (66) that is fixed to the container (61) and includes an outlet flow channel (OP) connected to the refrigerant discharge chamber (OR), wherein the at least one communication pipe (65) includes an outlet opening (65o) disposed in the refrigerant discharge chamber (OR) and at least one introduction-side refrigerating machine oil return hole (65d) disposed in the refrigerant introduction chamber, the at least one outlet pipe (66) includes an inlet opening (66i) disposed in the refrigerant discharge chamber (OR) and at least one discharge-side refrigerating machine oil return hole (66d) disposed in the refrigerant discharge chamber (OR), and oil returning capability of the at least one discharge-side refrigerating machine oil return hole (66d) is higher than oil returning capability of the at least one introduction-side refrigerating machine oil return hole (65d).

2. The accumulator (7) according to claim 1, wherein a sum total (ΣAcp) of a cross-sectional area of the communication flow channel (CP) is larger than a sum total (ΣAop) of a cross-sectional area of the outlet flow channel, a distance (Lc) from an inlet opening (65i) of the at least one communication pipe (65) to the at least one introduction-side refrigerating machine oil return hole (65d) is longer than a distance (Lo) from the inlet opening (66i) of the at least one outlet pipe (66) to the at least one discharge-side refrigerating machine oil return hole (66d), and a sum total (ΣAod) of an opening area of the discharge-side refrigerating machine oil return hole (66d) is equal to or larger than a sum total (ΣAcd) of an opening area of the introduction-side refrigerating machine oil return hole (65d).

3. The accumulator (7) according to claim 1 or b wherein the at least one introduction-side refrigerating machine oil return hole (65d) includes a plurality of the introduction-side refrigerating machine oil return holes (65d), the at least one discharge-side refrigerating machine oil return hole (66d) includes a plurality of the discharge-side refrigerating machine oil return holes (66d), and the number of the discharge-side refrigerating machine oil return holes (66d) is larger than the number of the introduction-side refrigerating machine oil return holes (65d).

4. The accumulator (7) according to any one of claims 1 to 3, wherein the at least one outlet pipe (66) includes at least one second discharge-side refrigerating machine oil return hole (66d2) that is placed to be closer to the inlet opening (66i) of the at least one outlet pipe (66) than the at least one discharge-side refrigerating machine oil return hole (66d).

5. The accumulator (7) according to claim 4, wherein a plurality of the second discharge-side refrigerating machine oil return holes (66d2) is arranged in an extending direction of the at least one outlet pipe (66), and the second discharge-side refrigerating machine oil return hole (66d2) closer to the inlet opening (66i) of the at least one outlet pipe (66) has a larger opening area.

6. The accumulator (7) according to claim 4 or 5 that can be installed so as to place the inlet opening (66i) of the at least one outlet pipe (66) above the outlet opening (65o) of the at least one communication pipe (65), and prevent the inlet opening (66i) of the at least one outlet pipe (66) from overlapping the outlet opening (65o) of the at least one communication pipe (65) in a vertical direction, and place the second discharge-side refrigerating machine oil return hole (66d2) below the outlet opening (65o) of the communication pipe (65).

7. The accumulator (7) according to claim 4 or 5 that can be installed so as to place the inlet opening (66i) of the at least one outlet pipe (66) above the outlet opening (65o) of the at least one communication pipe (65), and prevent the inlet opening (66i) of the at least one outlet pipe (66) from overlapping the outlet opening (65o) of the at least one communication pipe (65) in a vertical direction, and place the second discharge-side refrigerating machine oil return hole (66d2) above the outlet opening (65o) of the communication pipe (65).

8. A compressor (2) comprising: a sealed container (11); a compression mechanism (13) housed in the sealed container; an electric motor (12) that is housed in the sealed container and generates driving force of the compression mechanism (13); and the accumulator (2) according to any one of claims 1 to 7 that is placed outside the sealed container (11) and connected to a suction side of the compression mechanism (13).

9. A refrigeration cycle apparatus (1) comprising: the compressor (2) according to claim 8; a radiator (3); an expansion device (5); a heat absorber (6); and refrigerant piping (8) that connects the compressor (2), the radiator (3), the expansion device (5), and the heat absorber (6) to circulate a refrigerant.

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