JP2001082368A - Two-stage compression type rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the compression efficiency of the whole of a device to suppress a pressure loss, incurring when discharge refrigerant gas of a low stage compression element is sucked in a high-stage compression element, as much as possible. SOLUTION: A motor-driven element 14 and a rotary compression element 18 consisting of a low stage compression element 32 driven by the motor-driven element 14, and a high stage compression element 34 are situated at the internal part of a closed container 12. The discharge side of the low stage element 32 and the suction side of the high-stage compression element 34 are directly interconnected through communication passages 100 and 102 to form a two-state compression mechanism. A refrigerant compressed by the low stage compression element 32 is discharged to the internal part of the closed container 12. In a so formed two-stage compression type rotary compressor 10 wherein the internal pressure of the closed container 12 forms an intermediate pressure, confluent means 110 and 112 are provided to cause a refrigerant in the closed container 12 to be confluent with the communication passages 100 and 102 and feed it to the suction side of the high-stage compression element 34.

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 in which the internal space of a closed vessel is set at an intermediate pressure.

[0002]

2. Description of the Related Art Conventionally, in a two-stage compression type rotary compressor in which a motor-driven element and two rotary compression elements driven by the motor-driven element are arranged and housed in a closed vessel, a structure in which the closed vessel is set to an internal intermediate pressure is used. Proposed.

Specifically, as shown in FIGS. 3 and 4,
A drive motor 1005 is connected to an upper portion in the closed container 1003, and a rotation shaft 1005c of the drive motor 1005 is connected to a lower portion,
In addition, a rotary compression mechanism (a low-pressure compression mechanism 1007 at the top, a high-pressure compression mechanism 1009 at the bottom) and an oil sump at the bottom are arranged in two stages, and the cylinders of the low-pressure compression mechanism 1007 and the high-pressure compression mechanism 1009 are sucked. The back of a vane 1007c (1009c) partitioned into a compression chamber and a compression chamber
03 and the vane 1007c (10
09c) and the reaction force of the spring device and the closed container 1
003 and the internal pressure.

[0004] The refrigerant gas discharged from the low-pressure compression mechanism 1007 is supplied to an external gas-liquid separator 1 via a discharge pipe 1007e.
017, and flows again into the internal space of the sealed container 1003 through the communication pipe 1009d ', and
5 is cooled.

[0005] After that, the refrigerant gas flowing into the sealed container 1003 is passed through the suction pipe 1009d to the high-pressure compression mechanism 1003.
9 is introduced.

[0006] The discharged refrigerant gas recompressed by the high-pressure compression mechanism 1009 is supplied to an external condenser 1 via a discharge pipe 1009e.
013, the expansion valve 1015, the gas-liquid separator 101
7. The suction pipe 1007d is sequentially passed through the evaporator 1021.
To return to the low pressure compression mechanism to realize the vapor compression refrigeration cycle.

[0007]

However, in the above-described conventional apparatus, the refrigerant gas discharged from the low-pressure compression mechanism 1007 flows into the internal space of the closed casing 1003 and passes through the upper space in which the drive motor 1005 is arranged. Thus, it is sucked into the high-pressure compression mechanism 1009. For this reason, when the refrigerant gas flowing into the closed container 1003 passes through the space in which the drive motor 1005 is disposed, a pressure loss occurs, and
This has led to a reduction in the compression efficiency of the entire apparatus.

When the refrigerant gas passes through the space in which the drive motor 1005 is disposed, the temperature of the refrigerant gas rises due to the heat transfer from the drive motor 1005, and the high-pressure compression mechanism 1009
There is a problem that the temperature of the refrigerant gas discharged from the nozzle becomes high. In particular, when carbon dioxide is used as the refrigerant, there is a problem that the carbon dioxide refrigerant is likely to be heated to a high temperature because it has better heat conductivity than other refrigerants.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and minimizes the pressure loss generated when a refrigerant gas discharged from a low-pressure compression mechanism is sucked into a high-pressure compression mechanism, thereby improving the compression efficiency of the entire apparatus. It is another object of the present invention to provide a two-stage compression type rotary compressor in which the temperature rise of the refrigerant gas discharged from the high-pressure compression mechanism is reduced.

[0010]

According to the present invention, an electric element and a rotary compression element comprising 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. A two-stage compression type rotary compressor having an internal pressure of the hermetic container as an intermediate pressure, wherein a refrigerant inside the hermetic container is joined to the communication passage and supplied to a suction side of the high-stage compression element It is characterized by having a merging means.

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

More specifically, the electric element is disposed in an upper space of the closed container, the rotary compression element is disposed in a lower space of the electric element, and the joining means includes
A refrigerant discharge portion formed in the closed container housing portion between the space for disposing the electric element and the space for disposing the rotary compression element; and a merging passage connecting the refrigerant discharge portion and the communication passage. It is good also as composition.

Further, a configuration may be employed in which a carbon dioxide refrigerant is used to compress the gas to a supercritical pressure or higher. By using this configuration, it is possible to suppress 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 particularly good heat conductivity is used.

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

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the heat exchanger of 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 type rotary compressor according to an embodiment of the present invention.

In FIG. 1, a two-stage compression type rotary compressor 10 according to the present embodiment includes a cylindrical hermetic container 12 made of a steel plate, and a drive motor 14 as an electric element disposed in an upper space inside 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.

The closed container 12 has an oil reservoir at the bottom, and accommodates the motor 14 and the rotary compression mechanism 18.
A and a lid 1 for sealing the upper opening of the container body 12A.
2B, and an electric motor 14 on the lid 12B.
A terminal terminal (supply wiring is omitted) 20 for supplying external electric power is attached to the terminal.

The electric motor 14 comprises a stator 22 mounted annularly along the inner periphery of the upper space of the closed casing 12, and a rotor 24 arranged inside the stator 22 with a slight gap therebetween. The rotor 24 is integrally provided with a crankshaft 16 extending vertically through the center thereof.

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. The rotor 24 is also formed of a laminated body 30 of electromagnetic steel sheets, like the stator 22. In the present embodiment, an AC motor is used as the electric motor 14, but a DC motor may be used by embedding a permanent magnet.

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, which rotate inside the upper and lower cylinders 38, 40 by being connected to upper and lower eccentric portions 42, 44 provided on the crankshaft 16. 48 and the upper and lower rollers 4
The upper and lower vanes 50, 52 which contact the upper and lower cylinders 38, 40 to partition the interior of the upper and lower cylinders 38, 40 into a suction chamber (suction side) and a compression chamber (discharge side), and close the respective opening surfaces of the upper and lower cylinders 38, 40. The crankshaft 16 includes an upper support member 54 and a lower support member 56 which also serve as bearings.

The upper and lower support members 54 and 56 are connected to the upper and lower cylinders 3 through valve devices (not shown).
Discharge muffling chambers 58 and 60 are formed, which are appropriately connected to the upper and lower plates 62 and 40.
And the lower plate 64.

The upper and lower vanes 50, 52 are slidably disposed in radial guide grooves 66, 68 formed in the cylinder walls of the upper and lower cylinders 38, 40, and are vertically slid by springs 70, 72. 48 is constantly biased.

The upper cylinder 38 performs a first-stage (low-stage) compression operation, and the lower cylinder 40 performs a second-stage (high-stage) compression of the refrigerant gas compressed by the upper cylinder 38. A compression action is performed.

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 connected and fixed together with the upper plate 62 and the lower plate 64 using a plurality of mounting bolts 74.

The crankshaft 16 has a straight oil hole 76 in the center of the shaft and a horizontal oil supply hole 7 in the hole 76.
Spiral oil supply grooves 82 and 84 are formed on the outer peripheral surface of the oil supply grooves 82 and 84 so as to supply oil to the bearings and the sliding parts.

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

In the rotary compression mechanism 18, the carbon dioxide refrigerant is compressed and discharged to a supercritical pressure (7.39 MPa). Specifically, the low-stage compression element 3
In No. 2, the suction-side refrigerant pressure is 3 MPa, and the discharge-side refrigerant pressure is 7.5 MPa. Then, the high-stage compression element 34
, 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 a supercritical pressure on the high side of the refrigeration cycle, whereas the conventional vapor compression cycle operates at a 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 temperature of the refrigerant decreases. For this reason, in such a supercritical cycle, a cooling device is distinguished from a conventional subcritical pressure cycle condenser.

The upper and lower cylinders 38 and 40 have upper and lower refrigerant suction passages (not shown) for introducing the refrigerant, and upper and lower refrigerant discharge passages 86 for discharging the compressed refrigerant through the discharge muffling chambers 58 and 60. , 88 are provided. And
Connecting pipes 90, 92, 94, 96 fixed to the sealed container 12 are provided in the respective refrigerant suction passages and the refrigerant discharge passages 86, 88.
Are connected to the refrigerant pipes 98, 100, 102, 104. 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 for reducing 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 the heat exchange is decompressed by a 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
The pressure is reduced to a pressure (= 7.5 MPa) equal to the discharge side refrigerant pressure of No. 2.

Thus, the suction muffler 10
In 6, the high-temperature discharge refrigerant of the low-stage compression element 32 flowing through the refrigerant pipe 100 is cooled by the low-temperature refrigerant from the pressure reducing means flowing through 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 for communicating the discharge muffling chamber 58 of the upper support member 54 and the internal space of the closed container 12 with each other. 32), a part of the compressed refrigerant gas is directly discharged into the closed vessel 12, and then merges with the compressed refrigerant gas discharged through the refrigerant discharge passage 86 and the connection pipe 92 by the merge pipe 110 connected to the refrigerant pipe 100. Configuration.

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

As described above, the compressed refrigerant gas of the low-stage compression element 32 discharged into the closed casing 12 through the discharge pipe 108 joins the refrigerant pipe 100 through the connection pipe 112 and the junction 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 is also discharged into the closed vessel 12, and then the connection pipe 112 and the junction pipe 110 are discharged. And joins the refrigerant pipe 100.

As described above, the connection pipe 112 serving as a refrigerant discharge portion 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 is disposed in the closed container 12. As in the case, the refrigerant gas is
The generation of pressure loss by passing through the arrangement space 4 is suppressed.

Further, instead of supplying the refrigerant gas in the closed vessel 12 directly to the suction side of the high-stage compression element 34 as in the conventional apparatus described above, 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 vessel 12 via 100, 110, and 102 and is again supplied to the suction side of the high-stage compression element 34, it is cooled by the outside air and a cooling means such as the suction muffler 106 is used. With this arrangement, 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 good heat conductivity is used, this effect is more remarkable.

Further, the connection pipe 112, the refrigerant pipe 100
, The discharge side of the low-stage compression element 32 and the high-stage compression element 3
If the suction side of the compressor 4 is connected only in series via the communication passages 100 and 102, the cooling effect of the electric motor 14 cannot be expected, and the influence of the discharge pulsation of the refrigerant gas discharged from the low-stage compression element 32. However, the configuration described above allows the electric motor 14 to be cooled, and 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 Since the air is supplied to the suction side of the compression element 34, the internal space of the sealed container 12 plays a role of reducing the discharge pulsation of the refrigerant gas.

Regarding this point, as a result of experiments 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 those of the present invention, the compression efficiency was 50% in the case of the direct discharge only configuration. In contrast, the compression efficiency was 53.6% in the configuration of the present invention, whereas the compression efficiency was high with the configuration of the present invention.

Next, an outline of the operation of the two-stage compression type 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. This rotation causes the upper and lower rollers 46 and 48 connected to the upper and lower eccentric portions 42 and 44 provided integrally with the crankshaft 16 to eccentrically rotate inside the upper and lower cylinders 38 and 40. As a result, as shown in FIG. 2, the suction port 11 passes through the refrigerant pipe 98 and the refrigerant suction passage (not shown).
The first stage compression of the refrigerant gas sucked from 4 into the suction chamber 38a of the upper cylinder 38 is performed 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.
A part of the intermediate-pressure refrigerant gas discharged to 8 is discharged from the discharge pipe 108 into the closed casing 12, and the remaining part is sent out to the refrigerant pipe 100 through the refrigerant discharge passage 86 of the upper cylinder 38, and flows therethrough. It merges with the refrigerant gas discharged into the closed container 12 flowing from the pipe 110.

Next, the refrigerant gas after merging passes through the suction muffler 106, passes through the refrigerant pipe 102 and a refrigerant suction passage (not shown), and a suction port 118 shown in the drawing.
The intermediate-pressure refrigerant gas sucked into the low-pressure chamber 40a of the lower cylinder 40 is compressed by the lower roller 48 and the lower vane 52 in the second stage. The high-pressure refrigerant gas discharged from the compression chamber 40b of the lower cylinder 40 to the discharge muffle 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) constituting
Sent to Thereafter, the suction, compression, and discharge of the refrigerant gas are performed in the same route.

The rotation of the crankshaft 16 causes the lubricating oil stored at the bottom of the closed container 12 to be removed from the crankshaft 1.
6 rises in a vertical oil hole 76 formed in the center of the shaft, and flows out into helical oil supply grooves 82 and 84 formed in the outer peripheral surface from horizontal oil supply holes 78 and 80 provided in the middle. Thereby, the bearing of the crankshaft 16 and the upper and lower rollers 4
6, 48 and the sliding portions of the vertical eccentric portions 42, 44 are favorably lubricated, and as a result, the crankshaft 16 and the vertical eccentric portions 42, 44 can rotate smoothly.

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

[0044]

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

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a main part of an internal intermediate pressure type two-stage compression type rotary compressor according to 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 diagram of a refrigeration cycle using a conventional two-stage compression type rotary compressor.

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

[Explanation of symbols]

 Reference Signs List 10 Internal intermediate pressure type two-stage compression type rotary compressor 12 Cylindrical hermetic 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, Reference Signs List 40 Upper and lower cylinders 42, 44 Upper and lower eccentric portions 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 Merging pipe (merging passage) 112 Connecting pipe (refrigerant discharge part)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiyuki Ehara 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Takashi Yamakawa 2-chome Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. F-term (reference) 3H029 AA04 AA09 AA13 AB03 AB05 BB11 BB12 BB43 BB51 CC07 CC23 CC24 CC25 CC46 CC47

Claims (5)

[Claims] An electric element and a rotary compression element including 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 Forming a two-stage compression mechanism in which the suction side of the high-stage compression element is connected in series via a communication path, discharging the refrigerant compressed by the low-stage compression element into the closed container, A two-stage compression type rotary compressor having an intermediate pressure, comprising a joining unit that joins the refrigerant inside the closed container to the communication path and supplies the refrigerant to the suction side of the high-stage compression element. Features Two-stage compression type rotary compressor. 2. The electric motor according to claim 1, wherein the electric element is disposed in an upper space of the closed container, and the rotary compression element is disposed in a lower space of the electric element. 2. The air conditioner according to claim 1, further comprising: a refrigerant discharge portion formed in the closed container housing portion between the space where the compression element is arranged, and a merging passage connecting the refrigerant discharge portion and the communication passage. 3. A two-stage compression type rotary compressor according to claim 1. 3. The two-stage compression type rotary compressor according to claim 1, 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 type rotary compressor. 5. The two-stage compression type rotary compressor according to claim 1, further comprising cooling means for cooling a refrigerant supplied to a suction side of the high-stage compression element.