JP3370026B2 - 2-stage compression type rotary compressor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stage compression type rotary compressor, and more particularly to a two-stage compression type rotary compressor having an internal space of a hermetic container as an intermediate pressure.

[0002]

2. Description of the Related Art Conventionally, in a two-stage compression type rotary compressor in which an electric element and two rotary compression elements driven by the electric element are arranged and housed in a closed container, the closed container has an internal intermediate pressure. Proposed.

Specifically, as shown in FIGS. 3 and 4,
A drive motor 1005 is connected to an upper part of the closed container 1003, and a rotating shaft 1005c of the drive motor 1005 is connected to a lower part of the closed container 1003.
In addition, a rotary compression mechanism (a low pressure compression mechanism 1007 in the upper part and a high pressure compression mechanism 1009 in the lower part) formed in upper and lower two stages and an oil sump at the bottom are arranged to suck the cylinders of the low pressure compression mechanism 1007 and the high pressure compression mechanism 1009. The back of the vane 1007c (1009c) that divides the chamber and the compression chamber is the closed container 10.
03 open to the interior space of vane 1007c (10
09c) back pressure biasing force to the reaction force of the spring device and the closed container 1
It is formed by the internal pressure of 003.

The refrigerant gas discharged from the low-pressure compression mechanism 1007 is discharged to the external gas-liquid separator 1 via the discharge pipe 1007e.
017 is connected to the driving electric motor 100 through the communication pipe 1009d ′ into the internal space of the closed container 1003 again.
Cool 5

After that, the refrigerant gas flowing into the closed container 1003 is introduced into the high pressure compression mechanism 100 through the suction pipe 1009d.
Introduced in 9.

The discharged refrigerant gas recompressed by the high-pressure compression mechanism 1009 is discharged through the discharge pipe 1009e to the external condenser 1
013, expansion valve 1015, gas-liquid separator 101
7 and an evaporator 1021, and then a suction pipe 1007d.
Returning to the low-pressure compression mechanism again, the vapor compression refrigeration cycle is realized.

[0007]

However, in the above-mentioned conventional apparatus, the refrigerant gas discharged from the low-pressure compression mechanism 1007 flows into the internal space of the closed container 1003 and passes through the upper space in which the drive motor 1005 is arranged. And is sucked into the high pressure compression mechanism 1009. Therefore, pressure loss occurs when the refrigerant gas flowing into the closed container 1003 passes through the space where the drive motor 1005 is arranged,
The compression efficiency of the entire device is lowered.

Further, when the refrigerant gas passes through the space where the drive motor 1005 is arranged, heat transfer from the drive motor 1005 causes the temperature of the refrigerant gas to rise, and the high pressure compression mechanism 1009.
There is a problem in that the temperature of the refrigerant gas discharged from the inside becomes high. In particular, when carbon dioxide is used as the refrigerant, there is a problem that the carbon dioxide refrigerant tends to reach a high temperature because it has better heat conductivity than other refrigerants.

The present invention has been made in view of the above problems, and suppresses the pressure loss generated when sucking the refrigerant gas discharged from the low pressure compression mechanism into the high pressure compression mechanism as much as possible to improve the compression efficiency of the entire apparatus. An object of the present invention is to provide a two-stage compression type rotary compressor that suppresses the temperature rise of the refrigerant gas discharged from the high pressure compression mechanism.

[0010]

According to the present invention, an electric element and a rotary compression element composed of a low-stage compression element and a high-stage compression element driven by the electric element are arranged inside a closed container, A two-stage compression mechanism is formed in which the discharge side of the high-stage compression element and the suction side of the high-stage compression element are connected in series via a communication path, and the refrigerant compressed by the low-stage compression element is discharged into the closed container. And a two-stage compression rotary compressor in which the internal pressure of the closed container is set to an intermediate pressure, and the refrigerant inside the closed container is joined to the communication passage and supplied to the suction side of the high-stage compression element. It is characterized by having a merging means.

By using this configuration, it is possible to suppress the pressure loss generated when the refrigerant gas discharged from the low-stage compression element is sucked into the high-stage compression element as much as possible, and improve the compression efficiency of the entire apparatus.

[0012] Specifically, the electric element is arranged in the upper space of the closed container, the rotary compression element is arranged in the lower space of the electric element, and the merging means is
A refrigerant discharge part formed in the closed casing body between the electric element arrangement space and the rotary compression element arrangement space, and a confluence passage connecting the refrigerant discharge portion and the communication passage. It may be configured.

It is also possible to use a carbon dioxide refrigerant to compress to a pressure above the supercritical pressure. By using this configuration, it is possible to prevent the temperature of the refrigerant supplied to the suction side of the high-stage compression element from becoming high even when a carbon dioxide refrigerant having a particularly high heat transfer property is used.

Further, a cooling means for cooling the refrigerant supplied to the suction side of the high-stage compression element may be provided. By using this configuration, the refrigerant gas supplied to the suction side of the high-stage compression element can be further cooled.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a heat exchanger according to the present invention will be described below with reference to the drawings shown below.
FIG. 1 is a longitudinal sectional view of a main part of an internal intermediate pressure type two-stage compression rotary compressor which is an embodiment of the present invention.

In FIG. 1, a two-stage compression rotary compressor 10 of the present embodiment is a cylindrical hermetic container 12 made of a steel plate, and a drive motor 14 as an electric element arranged in an upper space in the hermetic container 12. , And the electric motor 14
And a rotary compression mechanism 18 as a compression element driven by a crankshaft 16 connected to the electric motor 14.

Further, the closed container 12 has an oil reservoir at the bottom and houses the electric motor 14 and the rotary compression mechanism 12.
A and a lid 1 for sealing the upper opening of the container body 12A
2B and two members. The lid 12B has an electric motor 14
A terminal terminal (power supply wiring is omitted) 20 for supplying external power is attached to.

The electric motor 14 comprises a stator 22 mounted annularly along the inner circumference of the upper space of the hermetically sealed container 12, and a rotor 24 arranged inside the stator 22 with a slight gap. The rotor 24 is integrally provided with a crankshaft 16 that extends vertically through the center of the rotor 24.

The stator 22 has a laminated body 26 in which ring-shaped electromagnetic steel sheets are laminated, and a plurality of coils 28 wound around the laminated body 26. Further, the rotor 24 is also composed of a laminated body 30 of electromagnetic steel plates, like the stator 22. Although an AC motor is used as the electric motor 14 in the present embodiment, a permanent magnet may be embedded to form a DC motor.

The rotary compression mechanism 18 includes a low stage compression element 32 and a high stage compression element 34. That is, the intermediate partition plate 36
And upper and lower cylinders 38, 40 provided above and below the intermediate partition plate 36, and upper and lower rollers 46, 46 connected to the upper and lower eccentric portions 42, 44 provided on the crankshaft 16 to rotate. 48 and the upper and lower rollers 4
The upper and lower vanes 50 and 52 that contact the upper and lower cylinders 38 and 40 by partitioning the upper and lower cylinders 38 and 40 into a suction chamber (suction side) and a compression chamber (discharge side), and the opening surfaces of the upper and lower cylinders 38 and 40 are closed. The crankshaft 16 is composed of an upper support member 54 and a lower support member 56 that also serve as the bearings of the crankshaft 16.

The upper and lower support members 54 and 56 are connected to the upper and lower cylinders 3 through a valve device (not shown).
The discharge muffling chambers 58 and 60 are formed so as to be in proper communication with the chambers 8 and 40, and the openings of these chambers are formed by the upper plate 62
And is closed by the lower plate 64.

The upper and lower vanes 50, 52 are slidably arranged in radial guide grooves 66, 68 formed in the cylinder walls of the upper and lower cylinders 38, 40, and springs 70, 72 are used for the upper and lower rollers 46, 46. It is biased so as to always come into contact with 48.

In the upper cylinder 38, the first stage (lower stage side) compression action is performed, and in the lower cylinder 40, the second stage (high stage side) that further compresses the refrigerant gas compressed by the upper cylinder 38. A compression action is performed.

Then, the upper support member 54, the upper cylinder 38, and the intermediate partition plate 3 which constitute the rotary compression mechanism 18 described above.
6, the lower cylinder 40 and the lower support member 56 are arranged in this order, and are connected and fixed together with the upper plate 62 and the lower plate 64 using a plurality of mounting bolts 74.

Further, the crankshaft 16 has a straight oil hole 76 in the center of the shaft and a lateral oil supply hole 7 in the hole 76.
Spiral oil supply grooves 82, 84 which are continuous through 8, 80 are formed on the outer peripheral surface to supply oil to the bearing and each sliding portion.

In this embodiment, carbon dioxide (CO ₂ ) which is a natural refrigerant is used as the refrigerant in consideration of the global environment, flammability, toxicity and the like, and the oil as the lubricating oil is, for example, mineral oil ( Existing oils such as mineral oil), alkylbenzene oil, PAG oil (polyalkylene glycol oil), ether oil, ester oil are used.

In the rotary compression mechanism 18, the carbon dioxide refrigerant is compressed to a supercritical pressure (7.39 MPa) and discharged. Specifically, the low-stage compression element 3
In 2, the suction side refrigerant pressure is 3 MPa and the discharge side refrigerant pressure is 7.5 MPa. And the high-stage compression element 34
In, the suction side refrigerant pressure is 7.5 MPa and the discharge side refrigerant pressure is 8 MPa. Here, the operation of the vapor compression cycle under supercritical conditions is performed at supercritical pressure on the high side of the refrigeration cycle, whereas the conventional vapor compression cycle is operated at subcritical pressure for evaporation and condensation. In the heat exchanger corresponding to the condenser in the conventional system, the refrigerant gas is not condensed but the refrigerant temperature is lowered. For this reason, in such a supercritical cycle, a cooling device is distinguished from a conventional condenser of a subcritical pressure cycle.

Further, in the upper and lower cylinders 38, 40, an upper and lower refrigerant suction passage (not shown) for introducing the refrigerant and an upper and lower refrigerant discharge passage 86 for discharging the compressed refrigerant through the discharge muffling chambers 58, 60. , 88 are provided. And
In each of the refrigerant suction passages and the refrigerant discharge passages 86, 88, connection pipes 90, 92, 94, 96 fixed to the closed container 12 are provided.
The refrigerant pipes 98, 100, 102, 104 are connected via the. Further, between the refrigerant pipes 100 and 102,
A suction muffler 106 acting as a gas-liquid separator is connected.

The suction muffler 106 is provided outside the compressor 10 and acts as a cooling device that lowers the temperature of the refrigerant discharged from the compressor 10 under supercritical conditions (acts as a condenser under normal conditions). In a heat exchanger (not shown), a part of the refrigerant after heat exchange is decompressed by decompression means (not shown) such as an expansion valve, and the refrigerant is joined via a refrigerant pipe 201. .

Here, in the pressure reducing means, the low-stage compression element 3 is used.
The pressure is reduced to a pressure equal to the discharge side refrigerant pressure of 2 (= 7.5 MPa).

As a result, this suction muffler 10
6, the high-temperature discharge refrigerant of the low-stage compression element 32 that flows in via the refrigerant pipe 100 is cooled by the low-temperature refrigerant from the pressure reducing means that flows in via the refrigerant pipe 201,
The refrigerant supplied to the suction side of the high-stage compression element 34 via the refrigerant pipe 102 has a lower temperature than the refrigerant discharged from the low-stage compression element 32. The suction muffler 106 functions as a cooling unit that cools the refrigerant supplied to the suction side of the high-stage compression element 34.

Further, the upper plate 62 is provided with a discharge pipe 108 which establishes communication between the discharge muffling chamber 58 of the upper support member 54 and the internal space of the closed container 12, and the first stage (low stage compression element). 32) A part of the compressed refrigerant gas is directly discharged into the closed container 12, and then merged with the compressed refrigerant gas discharged through the refrigerant discharge passage 86 and the connection pipe 92 by the merging pipe 110 connected to the refrigerant pipe 100. It is configured to do.

The merging pipe 110 serves as the refrigerant discharge portion fixed to the closed container body 12A between the upper space in which the electric motor 14 is arranged in the closed container 12 and the lower space in which the rotary compression mechanism 18 is arranged. Connection pipe 112 and refrigerant pipe 1
00 is the above-mentioned merging passage.

In this way, the compressed refrigerant gas of the low-stage compression element 32 discharged into the closed container 12 through the discharge pipe 108 joins the refrigerant pipe 100 through the connecting pipe 112 and the joining pipe 110. Has become. That is, the compressed refrigerant gas of the low-stage compression element 32 is directly discharged to the refrigerant pipe 100 via the refrigerant discharge passage 88 and the connection pipe 92, and after being discharged into the closed container 12, the connection pipe 112 and the confluent pipe 110. Is joined to the refrigerant pipe 100 via.

As described above, the connection pipe 112 as a refrigerant discharge part for discharging the refrigerant gas in the closed container 12 is provided in the lid 12B above the upper space in which the electric motor 14 in the closed container 12 is arranged. As in the case where the refrigerant gas is electric motor 1
It is possible to suppress pressure loss from passing through the arrangement space of No. 4.

Further, unlike the conventional apparatus described above, the refrigerant gas in the closed container 12 is not directly supplied to the suction side of the high-stage compression element 34, but the compressed refrigerant gas of the low-stage compression element 32 is supplied to the refrigerant pipe. Since it is once taken out of the closed container 12 via 100, 110, 102 and is supplied to the suction side of the high-stage compression element 34 again, it is cooled by the outside air and a cooling means such as the suction muffler 106 is provided. By providing the refrigerant gas, the refrigerant gas supplied to the suction side of the high-stage compression element 34 can be further cooled. In particular, since a carbon dioxide refrigerant having a good heat transfer property is used, this effect becomes more remarkable.

Further, the connecting pipe 112 and the refrigerant pipe 100
Without providing the discharge side of the low-stage compression element 32 and the high-stage compression element 3
When the suction side of No. 4 is simply connected in series via the communication passages 100 and 102, the cooling effect of the electric motor 14 cannot be expected, and the discharge pulsation of the refrigerant gas discharged from the low-stage compression element 32 is not effective. While the electric motor 14 can be cooled by the above-described configuration, a part of the refrigerant gas discharged from the low-stage compression element 32 is once discharged into the closed container 12, and then the high-stage compressor is easily received. Since it is supplied to the suction side of the compression element 34, the internal space of the closed container 12 plays a role of reducing the discharge pulsation of the refrigerant gas.

With respect to this point, as a result of conducting an experiment on the suction pressure and the discharge pressure of the low-stage compression element 32 and the high-stage compression element 34 under the same conditions as the above-mentioned constitution of the present invention, the compression efficiency is 50 in the case of only the direct discharge. While it was 0.0%, the compression efficiency was 53.6% in the above-mentioned constitution of the present invention, and it was confirmed that the compression efficiency was high by the constitution of the present invention.

Next, an outline of the operation of the above-described two-stage compression rotary compressor 10 shown in FIG. 1 will be described.

First, when power is supplied to the coil 28 of the electric motor 14 through the terminal terminal 20 and the power supply wiring (not shown), the rotor 24 rotates and the crankshaft 16 fixed thereto rotates. By this rotation, the upper and lower rollers 46, 48 connected to the upper and lower eccentric parts 42, 44 integrally provided with the crankshaft 16 eccentrically rotate in the upper and lower cylinders 38, 40. As a result, the suction port 11 as shown in FIG. 2 is passed through the refrigerant pipe 98 and the refrigerant suction passage (not shown).
The refrigerant gas sucked into the suction chamber 38a of the upper cylinder 38 from No. 4 is compressed in the first stage by the operation of the upper roller 46 and the upper vane 50. Then, the discharge muffling chamber 5 of the upper support member 54 is discharged from the compression chamber 38b via the discharge port 116.
Part of the intermediate pressure refrigerant gas discharged to 8 is discharged from the discharge pipe 108 into the closed container 12, and the rest is discharged to the refrigerant pipe 100 through the refrigerant discharge passage 86 of the upper cylinder 38, and is branched in the middle. It joins with the refrigerant gas discharged into the closed container 12 flowing in from the pipe 110.

Next, the combined refrigerant gas passes through the suction muffler 106, the refrigerant pipe 102 and the refrigerant suction passage (not shown), and the suction port 118 shown in FIG.
The intermediate-pressure refrigerant gas sucked into the low-pressure chamber 40a of the lower cylinder 40 is compressed in the second stage by the operation of the lower roller 48 and the lower vane 52. The high-pressure refrigerant gas discharged from the compression chamber 40b of the lower cylinder 40 to the discharge muffling chamber 60 of the lower support member 56 via the discharge port 120 passes from the refrigerant discharge passage 88 through the refrigerant pipe 104 to the vapor compression refrigeration cycle. External refrigerant circuit (not shown)
Sent to. After that, the suction, compression, and discharge of the refrigerant gas are performed by the same route.

Further, due to the rotation of the crankshaft 16, the lubricating oil stored in the bottom portion of the hermetically sealed container 12 can be removed from the crankshaft 1.
A vertical oil hole 76 formed in the center of the shaft 6 is lifted and flows out from horizontal oil supply holes 78, 80 provided in the middle thereof into spiral oil supply grooves 82, 84 formed on the outer peripheral surface. As a result, the bearing of the crankshaft 16 and the upper and lower rollers 4
6,48 and the vertical eccentric portions 42,44 are satisfactorily lubricated, and as a result, the crankshaft 16 and the vertical eccentric portions 42,44 can smoothly rotate.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. Further, the configuration of each part of the present invention is not limited to the above embodiment,
It goes without saying that various modifications can be made within the technical scope described in the claims.

[0044]

As described above, according to the present invention, the pressure loss generated when sucking the refrigerant gas discharged from the low-stage compression element into the high-stage compression element is suppressed as much as possible, and the compression efficiency of the entire apparatus is improved. In addition, the temperature rise of the refrigerant gas discharged from the rotary compression element can be suppressed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of an internal intermediate pressure type two-stage compression rotary compressor which is an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a main configuration of each compression element in FIG.

FIG. 3 is a piping system diagram of a refrigeration cycle using a conventional two-stage compression rotary compressor.

FIG. 4 is a schematic plan view of a compression mechanism of the compressor in FIG.

[Explanation of symbols]

10 Internal intermediate pressure type two-stage compression rotary compressor 12 Cylindrical closed container 14 Drive motor (electric element) 16 crankshaft 18 Rotary compression mechanism (rotary compression element) 32 Low-stage compression element 34 High-stage compression element 36 Intermediate partition plate 38, 40 upper and lower cylinders 42,44 Vertical eccentric part 46, 48 upper and lower rollers 50,52 upper and lower vanes 54 Upper support member 56 Lower support member 82,84 oil groove 110 Confluence pipe (merging passage) 112 Connection pipe (refrigerant discharge part)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Yamakawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (56) Reference JP-A-5-256285 (JP, A) JP Hei 2-23291 (JP, A) JP 11-241682 (JP, A) JP 6-17756 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F04C 23 / 00 F04C 29/00

Claims (5)

(57) [Claims] 1. An electric element and a rotary compression element composed of a low-stage compression element and a high-stage compression element driven by the electric element are arranged inside a closed container, and a discharge side of the low-stage compression element and the rotary side compression element. A two-stage compression mechanism is formed in which the suction side of the high-stage compression element is connected in series via a communication passage, and the refrigerant compressed by the low-stage compression element is discharged into the inside of the closed container, and the inside of the closed container. A two-stage compression rotary compressor having an intermediate pressure, wherein the refrigerant inside the closed container and the refrigerant passing through the communication passage are combined and supplied to the suction side of the high-stage compression element. A two-stage compression type rotary compressor, which is provided with a merging means. 2. The electric element is arranged in an upper space of the closed container, the rotary compression element is arranged in a lower space of the electric element, and the merging means is arranged in the arrangement space of the electric element and the rotary member. The refrigerant discharge part formed in the closed container casing part between the arrangement space of a compression element, and the confluence passage which connects the refrigerant discharge part and the communication passage are provided. The described two-stage compression rotary compressor. 3. The two-stage compression rotary compressor according to claim 1 or 2, wherein the refrigerant is carbon dioxide. 4. The method according to claim 1, wherein the refrigerant is compressed to a supercritical pressure or higher.
Stage compression rotary compressor. 5. The two-stage compression rotary compressor according to claim 1, further comprising cooling means for cooling the refrigerant supplied to the suction side of the high-stage compression element.