JP3370027B2 - 2-stage compression type rotary compressor - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a two-stage compression rotary compressor, and more particularly to a two-stage compression rotary compressor using a carbon dioxide refrigerant.

[0002]

2. Description of the Related Art Conventionally, a two-stage compression system in which an electric element and two rotary compression elements driven by a crankshaft connected to the electric element are arranged and housed in an airtight container, and the airtight inside of the airtight container has an intermediate pressure Rotary compressors have been 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]

In the above-mentioned conventional device, the low pressure compression mechanism 1007 and the high pressure compression mechanism 10 are used.
Suction pipes 1007d, 1010 for supplying the refrigerant to the suction side of 09
09d and a discharge pipe 1007 for discharging the refrigerant from the discharge side
e and 1009e are connected to the respective cylinders.

On the other hand, recently, from the viewpoint of global environmental problems,
The refrigeration cycle using a natural refrigerant that has little influence on the environment is being researched, and among these, the development of a compressor using a carbon dioxide refrigerant that is neither flammable nor toxic is earnestly desired.

However, when carbon dioxide is used as a refrigerant, the vapor compression cycle may be operated under supercritical conditions in the conventional condensation process due to the thermodynamic characteristics of carbon dioxide itself. The refrigerant pressure reaches about 8 to 10 MPa on the high pressure side and about 3 MPa on the low pressure side.
~ 4 MPa. As described above, the refrigerant pressure is higher and the differential pressure thereof is also larger than that of the fluorocarbon refrigerant conventionally used as the refrigerant.

Further, since the carbon dioxide refrigerant has a higher gas density than the conventional CFC refrigerant, sufficient refrigerating capacity can be obtained even when the volume flow rate of the refrigerant is small, and the displacement volume of the compressor is very small. Therefore, it is necessary to reduce the thickness of the cylinder (the height of the cylinder in the rotation axis direction) as compared with the conventional device from the viewpoint of preventing deterioration of compression efficiency and reducing bearing load.

Therefore, when the conventional compressor is used in a refrigeration cycle using a carbon dioxide refrigerant, the cylinder is provided with the connection hole as described above, and the suction pipe and the discharge pipe are directly connected to the cylinder. However, since the thickness of the cylinder is thin as described above, the suction pipe and the discharge pipe have to be made small in diameter in terms of pressure resistance.

Therefore, there is a problem in that the cross-sectional area of the refrigerant passage becomes small and the pressure loss becomes large as compared with the conventional device, resulting in a decrease in compressor efficiency.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a two-stage compression type rotary compressor in which the pressure loss is suppressed as much as possible and the compression efficiency of the entire apparatus is improved.

[0014]

According to the present invention, an electric element is provided inside a closed container, and a rotary compression element composed of a low-stage compression element and a high-stage compression element driven by a drive shaft connected to the electric element. And a discharge side of the low-stage compression element and a suction side of the high-stage compression element are connected in series via a communication pipe to form a two-stage compression mechanism. Stage compression element and high stage compression element are up and down
Each has an opening in the surface, and the low-stage compression element and the high-stage pressure
Is arranged between the compression elements and one opening of each compression element is
Intermediate partition plate to be closed and the other opening of the low-stage compression element
That also serves as the bearing part of the drive shaft while closing the part
Closing one support member and the other opening of the high-stage compression element
And a second support portion that also serves as a bearing portion of the drive shaft.
And a member, the support member, the compression element, and the middle member.
It has a fastening means to fasten it to the partition plate in the axial direction, uses carbon dioxide as a refrigerant , and cools the suction side of the low-stage compression element.
Compressed refrigerant from the discharge side and the low-stage side refrigerant introduction pipe that introduces the medium
A low-stage side refrigerant discharge pipe for discharging the
Connected to introduce refrigerant to the suction side of the high-stage compression element
High-stage side refrigerant introduction pipe and high-pressure side that discharges compressed refrigerant from the discharge side
The stage side refrigerant discharge pipe is connected to the second support member .

By using this structure, the inner diameters of the refrigerant introduction pipe and the refrigerant discharge pipe can be set regardless of the thickness of the cylinder.

More specifically, the first support member and
The second support member, for discharging said a suction passage for supplying to the suction side of the refrigerant the respective compression element from the refrigerant introducing pipe, the said respective refrigerant discharge pipe refrigerant from the discharge side of the compression element discharge It may be configured such that a passage is formed.

Further, the refrigerant may be compressed to a pressure higher than the supercritical pressure.

Further, the cooling means may be provided 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 cooled.

[0019]

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 low pressure two-stage compression rotary compressor which is an embodiment of the present invention.

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

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

The electric motor 14 comprises a stator 22 which is annularly mounted along the inner circumference of the upper space of the closed container 12, and a rotor 24 which is 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, 60 are formed so as to communicate with the discharge muffling chambers 8, 40, and the openings of these discharge muffling chambers are closed by an upper plate 62 and a 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 springs 70, 72 by means of springs 70, 72. 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 centered on the shaft and a lateral oil supply hole 7 in the hole 76.
Spiral oil supply grooves 82, 84 which are continuous with each other via 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) or higher and then discharged. Specifically, in the low-stage compression element 32, the suction side refrigerant pressure is 3 MPa and the discharge side refrigerant pressure is 7.5 MPa. In 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 the supercritical condition is performed at the supercritical pressure on the high side of the refrigeration cycle, while the conventional vapor compression cycle operates the evaporation and the condensation at a subcritical pressure. 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.

The upper support member 54 and the lower support member 56 have upper and lower refrigerant suction passages for introducing refrigerant into the upper and lower cylinders 38, 40, and a silencer chamber 58 for discharging compressed refrigerant.
Upper and lower refrigerant discharge passages 86, 88 for discharging via 60 are provided. The refrigerant suction passages and the refrigerant discharge passages 86, 88 are connected to the refrigerant pipes 98, 1 via connection pipes 90, 92, 94, 96 fixed to the closed container 12.
00, 102, 104 are connected.

In this way, the refrigerant pipes 98, 1 as the refrigerant introducing pipes for introducing the refrigerant into the suction sides of the respective compression elements 32, 34.
02 and the refrigerant pipes 100 and 104 as the refrigerant discharge pipes for discharging the compressed refrigerant from the discharge sides of the respective compression elements 32 and 34 are not directly connected to the upper and lower cylinders 38 and 40 of the compressor 10, but are supported on the upper side. Since they are respectively connected to the member 54 and the lower support member 56, the inner diameters of the refrigerant pipes 98, 100, 102, 104 can be set regardless of the thickness of the cylinder. Therefore, even when used in a refrigeration cycle using a carbon dioxide refrigerant, it is possible to reduce the pressure loss and improve the compression efficiency without reducing the refrigerant passage cross-sectional area.

Further, a suction muffler 10 acting as a gas-liquid separator is provided between the refrigerant pipes 100 and 102.
6 is connected.

The suction muffler 106 is provided outside the compressor 10 and acts as a cooling device for lowering the temperature of the refrigerant discharged from the compressor 10 under supercritical conditions (acting 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.

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 refrigerant gas sucked from the suction port 114 into the suction chamber 38a of the upper cylinder 38 via the refrigerant pipe 98 and the refrigerant suction passage is moved by the operation of the upper roller 46 and the upper vane 50 as shown in FIG. The first stage compression is performed. The intermediate-pressure refrigerant gas discharged from the compression chamber 38b to the discharge muffling chamber 58 of the upper support member 54 via the discharge port 116 is delivered to the refrigerant pipe 100 through the refrigerant discharge passage 86 of the upper cylinder 38. .

Next, the refrigerant gas from the refrigerant pipe 100 passes through the suction muffler 106, the refrigerant pipe 102, and the refrigerant suction passage (not shown), and from the suction port 118 shown in FIG. 2 to the low pressure chamber 40a of the lower cylinder 40. The sucked intermediate-pressure refrigerant gas is transferred to the lower roller 48 and the lower vane 52.
The second stage compression is performed by the operation of. 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. Is sent to an external refrigerant circuit (not shown) constituting the. 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 46,
Oil is satisfactorily supplied to the respective sliding portions of the 48 and the vertical eccentric portions 42 and 44, and as a result, the crankshaft 16 and the vertical eccentric portions 42 and 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.

Although the internal low-pressure two-stage compression rotary compressor has been described in the above embodiment, the present invention is not limited to this. For example, the pressure inside the closed container 12 is the pressure of the compressed refrigerant discharged from the low-stage compression element 32. It is also applicable to an internal intermediate pressure type two-stage compression rotary compressor. However, in this case, a separate discharge pipe for directly discharging a part of the compressed refrigerant gas of the low-stage compression element 32 into the closed container 12 is provided, and the refrigerant in the closed container 12 is joined to the refrigerant pipe 100 to make a high-stage discharge. It is necessary to supply the compression element 34 to the suction side. In this case, the cooling effect of the electric motor 14 can be expected, 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 compression element 3 is discharged.
Since it is supplied to the suction side of No. 4, the internal space of the closed container 12 serves to reduce the discharge pulsation of the refrigerant gas.

[0045]

As described above, according to the present invention, it is possible to set the inner diameters of the refrigerant pipes, which are the refrigerant introduction pipe and the refrigerant discharge pipe, regardless of the thickness of the cylinder. Even when used, it is possible to reduce the pressure loss and improve the compression efficiency without reducing the refrigerant passage cross-sectional area.

[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

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Yamakawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (56) Reference JP-A-11-241682 (JP, A) JP HEI 3-81592 (JP, A) JP-A-8-247061 (JP, A) JP-A-6-17756 (JP, A) Actual development Sho-47-26412 (JP, U) (58) Fields investigated (Int .Cl. ⁷ , DB name) F04C 23/00 F04C 18/356 F04C 29/00

Claims (4)

(57) [Claims] 1. An electric element inside a closed container, and an upper and lower surface driven by a drive shaft connected to the electric element.
A rotary compression element including a low-stage compression element and a high-stage compression element each having an opening, and the discharge side of the low-stage compression element and the suction side of the high-stage compression element are connected in series via a communication pipe. Form a connected two-stage compression mechanism
And a two-stage compression rotary compressor that uses carbon dioxide as a refrigerant , which is arranged between the low-stage compression element and the high-stage compression element.
An intermediate partition plate for closing one opening of the compression element, and another opening for closing the other opening of the low-stage compression element, and
The first support member that also serves as the bearing portion of the drive shaft and the other opening of the high-stage compression element are closed, and
The second support member that also serves as the bearing portion of the drive shaft, the support members, the compression elements, and the intermediate partition plate
A fastening means for fastening in the axial direction and a suction of the low-stage compression element, which is connected to the first support member.
The low-stage side refrigerant introduction pipe for introducing the refrigerant to the side, and the discharge of the low-stage compression element connected to the first support member
And a low-stage side refrigerant discharge pipe for discharging compressed refrigerant from the side , and suction of the high- stage compression element connected to the second support member.
High-stage side refrigerant introduction pipe for introducing refrigerant to the side, and discharge of the high-stage compression element connected to the second support member
A high-stage side refrigerant discharge pipe that discharges the compressed refrigerant from the side
2-stage compression type rotary compressor, characterized in that. 2. The first support member and the second support member,
A suction passage that supplies the refrigerant from each refrigerant introduction pipe to the suction side of each compression element and a discharge passage that discharges the refrigerant from the discharge side of each compression element to each refrigerant discharge pipe are formed. The two-stage compression type rotary compressor according to claim 1. 3. The two-stage compression rotary compressor according to claim 1, wherein the refrigerant is compressed to a supercritical pressure. 4. 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.