JP2000205164A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary compressor capable of adopting the conventional fundamental design unchanged substantially even when carbon dioxide is used as a refrigerant. SOLUTION: A compressing means is of a two-stage compression system consisting of a front stage compression element 20 and a rear stage compression element 30. The internal space of a sealed case 13 is coupled with the suction port 31 of the rear stage compressor 30 through a coupling pipe 40, which is fitted with a heat radiator 41. A refrigerant supplied externally to the front stage compression element 20 is compressed thereby and discharged into the sealed case 13 so that the temp. and pressure of the refrigerant are decreased. This refrigerant is fed to the rear stage compression element 30 via the heat radiator 41. At this time, the refrigerant releases the heat at the radiator 41, which decreases the temp. and pressure of the refrigerant still further. Even if a refrigerant of carbon dioxide is used, therefore, the specified pressure and temp. will never be exceeded, which allows adopting the conventional fundamental design unchanged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor having a plurality of compression elements.

[0002]

2. Description of the Related Art Conventionally, rotary compressors have been used in various technical fields, and have a compression means for compressing a refrigerant and a motor as a driving means for driving the compression means. It is configured to be stored in.

In such a rotary compressor, a refrigerant containing chlorine such as R-22 (hereinafter, referred to as a refrigerant) has been used.
(Specified Freon gas) was used, however, it was found that this particular Freon gas causes destruction of the ozone layer, and it was regulated.

[0004] Therefore, research and development of a refrigerant replacing the specific Freon gas have been actively conducted. Such refrigerants include carbon dioxide refrigerants.

[0005]

However, when a carbon dioxide refrigerant is used in a rotary compressor having a conventional structure on the assumption that a specific Freon gas is used, the minimum pressure of the refrigerant is about six times (about 30 to 30 times) as compared with the conventional one. 40 kg / cm ² G),
There is a problem that the maximum pressure becomes about four times (about 150 kg / cm ² G), the differential pressure becomes large, and the maximum pressure and the maximum temperature become extremely high.

For this reason, it is necessary to redo the basic design including the pressure resistance characteristics, the heat resistance characteristics, and the thermal characteristics of the lubricating oil of members such as a cylinder and a closed case which constitute the rotary compressor, which causes an increase in cost.

Further, even if the problems of pressure resistance and heat resistance in a cylinder, a closed case, etc. are solved, in the case of a structure in which the pressure of the refrigerant is high, the load of the driving means for driving the compression means increases (power consumption) Becomes large), and there is a problem that the compression efficiency is reduced as compared with the related art.

Accordingly, an object of the present invention is to provide a rotary compressor which can apply the conventional basic design as it is even when a carbon dioxide refrigerant is used and suppresses a decrease in compression efficiency.

[0009]

According to a first aspect of the present invention, there is provided a compressor for reducing the size of a compression chamber and compressing a refrigerant in the compression chamber, and a drive for driving the compression means. Means, a rotary compressor having a sealed case for housing these compression means and drive means, wherein the compression means sucks refrigerant from outside the machine, compresses it and discharges it into the sealed case, A heat dissipating means for exchanging heat in the sealed case with the outside air, and a latter-stage compression element which inhales the refrigerant dissipated by the heat dissipating means, compresses the compressed air and discharges it to the outside of the machine, for example, a carbon dioxide refrigerant In this case, the conventional basic design can be applied almost as it is, and a decrease in compression efficiency is suppressed.

According to a second aspect of the present invention, a heat radiating means is provided in a connecting pipe connecting the internal space of the sealed case and the suction port of the subsequent compression element, and a refrigerant flowing in the pipe is provided in the middle of the connecting pipe. And a radiator for exchanging heat with the outside air, with a simple configuration, for example, even when a carbon dioxide refrigerant is used, the conventional basic design can be applied almost as it is, and a decrease in compression efficiency is suppressed. It is characterized by the following.

A third aspect of the present invention is characterized in that a carbon dioxide refrigerant is used as the refrigerant.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of the rotary compressor 10,
The rotary compressor 10 according to the present invention has a motor 11 as a driving unit, a compression unit 12 provided below the motor 11, and the like. These are housed in a closed case 13, and a carbon dioxide refrigerant is used as a refrigerant. Used.

The lubricating oil 1 is provided at the bottom of the closed case 13.
4 for lubricating a sliding portion or the like in the compression means 12.

The compression means 12 comprises a first-stage compression element 20 and a second-stage compression element 30, and each of the compression elements 20, 30 is provided with suction ports 21, 31 and discharge ports 22, 32.

A connection pipe 40 is provided in the sealed case 13. One end of the connection pipe 40 is connected to the closed case 1
The other end is in communication with the suction port 31 of the rear compression element 30. A radiator 41 is provided in the connection pipe 40.

The compression mechanism of the first-stage compression element 20 and the second-stage compression element 30 have substantially the same configuration. Each of the compression elements 20 and 30 is provided with rollers 24 and 34 in cylindrical cylinders 23 and 33, respectively. The rollers 24 and 34 are formed in a cylindrical shape, and the cranks 25 and 35 are disposed inside the rollers 24 and 34, and a vane (not shown) is in contact with the outer surfaces of the rollers 24 and 34.

Since the cranks 25 and 35 are fixed to (or integrally formed with) the rotating shaft 15 of the motor 11, the rotation of the cranks 25 and 35 causes the rollers 24 and 3 to rotate.
4 makes eccentric rotational movement.

The rollers 24 of the first-stage compression element 20 and the rollers 34 of the second-stage compression element 30
The rotation phases are shifted by 180 degrees so that the vibrations generated by the eccentric rotational movement are offset.
That is, the crank 25 and the crank 35 are provided symmetrically about the rotation shaft 15.

One end of the outer surface of each of the rollers 24 and 34 is always in contact with the cylinders 23 and 33.
The space formed between the roller 33 and the rollers 24 and 34 has a crescent shape.

Since the vane is in contact with the outer surfaces of the rollers 24 and 34, the vane divides the crescent-shaped space into an intake chamber and a compression chamber (not shown).

Inner diameter of cylinders 23 and 33 and roller 2
Since the outer diameters of the rollers 4 and 34 do not change, the volume of the crescent-shaped space is always constant even when the rollers 24 and 34 rotate. However, as the rollers 24, 34 rotate, the rollers 24, 3
Since the contact position between 4 and the cylinders 23 and 33 changes, the direction of the crescent-shaped space changes.

On the other hand, the vanes move in and out of the cylinders 23 and 33 in the radial direction so as to always contact the outer surfaces of the rollers 24 and 34.

Accordingly, the volume ratio between the suction chamber and the compression chamber formed by dividing the crescent-shaped space by the vane changes according to the rotation of the rollers 24 and 34, and when the volume of the suction chamber is expanded, the volume of the compression chamber is reduced. The volume shrinks.

The suction chamber communicates with the suction ports 21 and 31, and the compression chamber communicates with the discharge ports 22 and 32 via a discharge valve (not shown). Then, as the rollers 24 and 34 cross the intake ports 21 and 31, the intake chamber becomes the discharge ports 22 and 3 respectively.
As a result, the suction chamber changes to a compression chamber.

The refrigerant is compressed as the compression chamber shrinks, and reaches the discharge pressure specified by the discharge valve.
Discharged from 2, 32.

The discharge port 32 of the latter compression element 30 is
Although not communicating with the space inside the closed case 13, the discharge port 22 of the pre-stage compression element 20 is connected with the space inside the closed case 13.

Since the space volume of the closed case 13 is large, when the refrigerant is discharged from the pre-compression element 20 into this space, it expands substantially adiabatically, so that the pressure of the refrigerant and the temperature of the refrigerant decrease.

The refrigerant whose temperature and pressure have been lowered in this way passes through the radiator 41 and exchanges heat with the outside air to radiate heat. As a result, the temperature and pressure are further reduced and supplied to the latter compression element 30. .

Needless to say, the outside air may be forcibly blown to the radiator 41, and another cooling medium such as cooling water may be used instead of the outside air.

As described above, the maximum pressure and the maximum temperature of the refrigerant in the second-stage compression element 30 can be suppressed, and there is no need to redo the basic design including the pressure resistance and the heat resistance evaluation of each member constituting the rotary compressor 10, and the refrigerant is not required. Does not become higher than a preset pressure, it is possible to suppress a decrease in compression efficiency.

Further, since the pressure at the suction port 31 of the latter-stage compression element is reduced, the refrigerant can be efficiently sucked, and in this respect, it is possible to suppress a decrease in compression efficiency.

[0032]

As described above, according to the first aspect of the present invention, the compression means has a two-stage structure of the first-stage compression element and the second-stage compression element, and the refrigerant compressed by the first-stage compression element is discharged into the closed case. However, since the refrigerant is radiated through the radiating means and supplied to the subsequent compression element, for example, even when a carbon dioxide refrigerant is used, the conventional basic design can be applied as it is and the compression efficiency can be reduced. It is possible to suppress the decrease.

According to the second aspect of the present invention, the heat radiating means is provided in the connecting pipe for connecting the internal space of the closed case to the suction port of the subsequent compression element, and is provided in the middle of the connecting pipe to flow in the pipe. Since it is constituted by a radiator for exchanging heat between the refrigerant and the outside air, even in the case of using a carbon dioxide refrigerant with a simple configuration, for example, the conventional basic design can be applied as it is, and a reduction in compression efficiency is suppressed. It becomes possible.

According to the third aspect of the present invention, a carbon dioxide refrigerant is used as the refrigerant, and the compression means has a two-stage structure of a first-stage compression element and a second-stage compression element. Since the refrigerant is discharged to the inside and the heat is radiated through the heat radiating means and supplied to the subsequent compression element, the conventional basic design can be applied almost as it is, and a decrease in the compression efficiency can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotary compressor applied to a description of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotary compressor 11 Motor 12 Compression means 13 Hermetic case 20 Pre-stage compression element 20, 30 Compression element 21, 31 Suction port 22, 32 Discharge port 30 Post-stage compression element 40 Connecting pipe 41 Heat radiator

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eiichi Shimizu 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Kazuya Sato 2-chome, Keihanhondori, Moriguchi-shi, Osaka No.5 Sanyo Electric Co., Ltd. (72) Inventor Makoto Ma 2-5-2-5 Keihan Hondori, Moriguchi City, Osaka Prefecture (72) Inventor Yasuo Sakamoto 2 Keihanhondori, Moriguchi City, Osaka Prefecture 5-5-5 Sanyo Electric Co., Ltd. F-term (reference) 3H029 AA04 AA09 AA13 AA21 AB03 BB12 BB42 CC02 CC23 CC47

Claims (3)

[Claims] 1. A rotary having a compression means for reducing a compression chamber to compress a refrigerant in the compression chamber, a driving means for driving the compression means, and a sealed case for accommodating the compression means and the driving means. In the compressor, the compression means takes in refrigerant from outside the compressor, compresses the refrigerant, discharges the refrigerant into the closed case, and cools the refrigerant from the closed case by exchanging heat with the outside air. A rotary compressor comprising: a heat dissipating means; and a latter-stage compression element that draws in the refrigerant cooled by the heat dissipating means, compresses the refrigerant, and discharges the compressed air to the outside of the machine. 2. A connecting pipe for connecting the internal space of the closed case and a suction port of the second-stage compression element, wherein the heat radiating means is provided in the middle of the connecting pipe, and a refrigerant flowing in the pipe and outside air are provided. The rotary compressor according to claim 1, further comprising a radiator for exchanging heat with the heat. 3. The rotary compressor according to claim 1, wherein a carbon dioxide refrigerant is used as said refrigerant.