JP2000097177A - Rotary compressor and refrigerating circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of a small rotary compressor using inexpensive carbon dioxide as a refrigerant and a refrigerating circuit using the rotary compressor. SOLUTION: In this rotary compressor 1 in which a rotary compression element 5 comprising cylinders 14, 15 whose both end openings are closed, rollers 16, 17 rotated in the inside of these cylinders 14, 15 and vanes 20, 21 forming a compression space in the inside of the cylinders 14, 15 by being brought into contact with the rollers 16, 17 is stored in the inside of a sealed container 2 and an absorbed refrigerant is compressed by the rotary compression element 5 and discharged, carbon dioxide is used as a refrigerant and the inner pressure of the rotary compressor 1 is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotary compressor using natural refrigerant, particularly carbon dioxide (CO ₂ ).

[0002]

2. Description of the Related Art Freon (R11, R12, R134a, etc.) has been generally used as a refrigerant in a refrigeration cycle. However, if CFCs are released into the atmosphere, they have problems such as a large warming effect and ozone layer depletion.

[0003] For this reason, in recent years, the impact on the environment has been small.
Other natural refrigerants such as oxygen (O _Two),carbon dioxide
(CO_Two), Hydrocarbon (HC), ammonia
(NH_Three), Water (H_TwoResearch using O) as refrigerant
Have been.

[0004] Of these natural refrigerants, oxygen and water cannot be used as refrigerants in a refrigeration cycle because of their low pressure even when used in rotary compressors. In addition, since ammonia and hydrocarbons are flammable, there is a problem that handling is difficult.

Therefore, development of a compressor using CO _2, ie, carbon dioxide, has been desired.

Conventionally, compressors of reciprocating type and rotary type (rotary type) are roughly classified. However, reciprocating type compressors have problems of noise and vibration.

Therefore, development of a rotary compressor using carbon dioxide has been desired.

[0008] Such a compressor using carbon dioxide,
JP-A-10-19401 (F25B 9/06)
Is disclosed. This compressor is generally called a Rotasco rotary compressor, and is used for high pressure.

[0009]

When carbon dioxide is used as a refrigerant in the Rotasco rotary compressor as described above, the refrigerant pressure is about 150 kg / cm on the high pressure side.
² G, and about 30 to 40 kg / cm ² G on the low pressure side.

As described above, in a refrigeration cycle using carbon dioxide as a refrigerant, the refrigerant pressure is higher than that of chlorofluorocarbon, and
The pressure difference is also large. In particular, when the refrigerant pressure becomes high, there is a problem that the sealed container that is the outer shell of the compressor cannot withstand and the compressor is damaged.

In order to solve this problem, the thickness of the closed container may be increased. However, there is a problem that the cost is high and the size is increased by the increased thickness.

In particular, in the case of the Rotasco rotary compressor as described above, it cannot withstand the pressure without further reinforcement.

Furthermore, in the case of the carbon dioxide refrigerant, the temperature of the discharged gas tends to be high, and the quality of the lubricating oil and the carbon dioxide refrigerant itself tends to deteriorate.

The present invention has been made in view of such problems, and has been made to improve the reliability of a small-sized and low-cost rotary compressor using carbon dioxide as a refrigerant and a refrigeration circuit using the rotary compressor. The purpose was.

[0015]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a cylinder having both ends closed, a roller rotating in the cylinder,
A rotary compressor that accommodates a rotary compression element consisting of a vane forming a compression space in the cylinder by contacting the roller in a closed container, and compresses and sucks the sucked refrigerant by the rotary compression element. The present invention provides a rotary compressor using carbon dioxide as a refrigerant and reducing the pressure inside the closed vessel.

The carbon dioxide compressed by the rotary compression element has a low critical point temperature, typically about 31 ° C. Therefore, when carbon dioxide is used as a refrigerant, the refrigerant is used in a gasified state, that is, in a supercritical region. In the supercritical region, the carbon dioxide refrigerant has a high pressure and a high vapor density.Therefore, in a high-pressure internal compressor, there is a problem that a load is applied to the closed vessel. The refrigeration capacity equivalent to that of other refrigerants can be exerted without imposing an unnecessary load on the sealed container of the rotary compressor.

According to the second aspect of the present invention, there is provided a cylinder having both ends closed, a roller rotating in the cylinder, and a vane forming a compression space in the cylinder by contacting the roller. In a rotary compressor that stores a rotary compression element in a closed container and compresses and discharges the sucked refrigerant by the rotary compression element, carbon dioxide is used as a refrigerant, and the inside of the closed container is set to an intermediate pressure. A rotary compressor is provided.

The carbon dioxide compressed by the rotary compression element has a low critical point temperature, typically about 31 ° C. Therefore, when carbon dioxide is used as a refrigerant, the refrigerant is used in a gasified state, that is, in a supercritical region. In the supercritical region, the carbon dioxide refrigerant has a high pressure and a high vapor density.Therefore, the internal high-pressure compressor has a problem that a load is applied to the sealed container.However, by using a rotary compressor with an internal intermediate pressure, The refrigeration capacity equivalent to that of other refrigerants can be exerted without imposing an unnecessary load on the sealed container of the rotary compressor.

According to a third aspect of the present invention, there is provided the rotary compressor according to the first or second aspect, wherein the rotary compression element comprises a plurality of stages.

As described above, by performing compression in a plurality of stages, the temperature of the discharge gas of the rotary compressor can be kept low. Therefore, the heat resistance of the rotary compressor can be improved, the deterioration of the carbon dioxide refrigerant itself and the lubricating oil can be prevented, and the reliability of the rotary compressor can be improved.

According to a fourth aspect of the present invention, there is provided a refrigeration circuit including the rotary compressor according to the third aspect, wherein a subcooler for lowering the temperature of refrigerant discharged from the rotary compressor is provided. A refrigeration circuit characterized by the following.

As described above, the compression is performed in a plurality of stages, and the refrigerant before entering the expansion valve is cooled by the supercooler.
The temperature of the gas discharged from the rotary compressor is reduced by the subcooler.

Accordingly, the heat resistance of the rotary compressor can be improved, and the deterioration of the carbon dioxide refrigerant itself and the lubricating oil can be prevented, whereby the reliability of the rotary compressor can be improved.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a two-cylinder rotary compressor equipped with the present invention, FIG. 2 is a refrigeration circuit diagram using a one-cylinder rotary compressor equipped with the present invention, and FIG. Mollier diagram in a refrigeration circuit diagram using a one-cylinder rotary compressor provided with: a refrigeration circuit diagram using a two-cylinder rotary compressor provided with the present invention; and FIG. FIG. 3 is a Mollier diagram in a refrigeration circuit diagram using a two-cylinder rotary compressor to be used.

1 is a two-cylinder rotary compressor (rotary compressor) equipped with the present invention.
An electric element 3 provided at an upper portion in a closed container 2 made of metal such as iron, and a rotary compression element 5 provided below the electric element 3 and driven to rotate by a rotation shaft 4 of the electric element 3. It becomes.

The hermetically sealed container 2 has an oil reservoir at its lower part, and includes a container 2A for accommodating the electric element 3 and the rotary compression element 5, and a sealing lid 2B for sealing the container 2A. A terminal terminal (wiring is omitted) 6 for supplying electric power to the electric element 3 is attached to the sealing lid 2B.

The electric element 3 is composed of a rotor 7 and a stator 8, and the rotor 7 is provided with a permanent magnet (not shown) inside a laminated body 10 composed of laminated electromagnetic steel sheets. The windings 11 are attached to a laminated body 12 in which a plurality of electromagnetic steel sheets are laminated.
In addition, 9 is a balancer. Although this structure is referred to as a DC motor, a motor referred to as an AC motor in which an aluminum core made of aluminum is inserted into a laminated electromagnetic steel plate may be used.

Further, when used for an air conditioner of a car or the like, an engine of the car or the like may be used as a drive source, or another drive source may be used.

The rotary compression element 5 includes a plate middle (intermediate partition plate) 13, upper and lower cylinders 14 and 15 mounted above and below the plate middle 13, and a rotating shaft 4 inside the upper and lower cylinders 14 and 15. Vertical eccentric part 16, 1
Upper and lower rollers 18 and 19 which are rotated by 7; upper and lower vanes 20 and 21 which contact the upper and lower rollers 18 and 19 to partition the inside of the upper and lower cylinders 14 and 15 into a high-pressure chamber and a low-pressure chamber;
The main frame 2 that closes the upper and lower openings of the upper and lower cylinders 14 and 15 and allows the rotation of the rotary shaft 4.
2, and a bearing plate 23.

Further, these are arranged in the order of a main frame 22, an upper cylinder 14, a plate middle 13, a lower cylinder 15, and a bearing plate 23, and are connected by bolts 24.

The rotary shaft 4 is provided with an oil supply hole 25 for supplying lubricating oil, that is, oil, to each sliding portion of the rotary compression element 5. Further, the outer peripheral surface of the rotating shaft 4 communicates with the oil supply hole 25 so that the oil is supplied to the upper and lower rollers 1.
An oil supply groove 26 leading to the inside of each of 8 and 19 is formed. Further, the upper and lower vanes 20 and 21 are provided with the upper and lower rollers 1.
A spring 27 for constantly biasing the springs 8 and 19 is provided.

The oil used as the lubricating oil may be an existing oil such as a mineral oil (mineral oil), an alkylbenzene oil, an ether oil or an ester oil.

The upper and lower cylinders 14 and 15 are provided with upper and lower introduction pipes (not shown) for introducing the refrigerant, and upper and lower outlet pipes 30 and 31 for discharging the refrigerant, respectively. Refrigerant pipes 32, 33, and 34 are connected to the upper and lower introduction pipes and the upper and lower outlet pipes 30, 31, respectively.

Reference numeral 35 denotes a pedestal for supporting the closed container 2, and reference numeral 36 denotes a suction muffler.

In the above description, the structure of the two-cylinder rotary compressor 1 has been described. However, a one-cylinder rotary compressor 50 may be used, and a refrigerant circuit for one cylinder will be described below.

In this case, as shown in FIGS. 2 and 3, a discharge side refrigerant pipe 51 of the rotary compressor 50 is connected to a condenser 52, and the condenser 52 and a cooler (evaporator) 53 are connected. And an expansion valve 54 connected to a refrigerant pipe 55. Further, the cooler 53 and the rotary compressor 50 are connected by a suction-side refrigerant pipe 56.

Accordingly, the gas refrigerant of carbon dioxide, which has been compressed by the one-cylinder rotary compressor 50 and has become high temperature, is cooled by the condenser 52 and expanded by the expansion valve 54.
It flows into the cooler 53. Here, the collected gas refrigerant is
It returns to the rotary compressor 50 again from the suction side refrigerant pipe 56.

In FIG. 3, point I is the suction pressure of the rotary compressor 50, which is about 30 kgf / cm ² G, and point J indicates the discharge pressure of the rotary compressor 50. It has become.

In the case of the rotary compressors 1 and 50 of the present invention, the refrigerant discharge pressure is about 100 to 130 kgf / cm ² G.
It is.

The point K is the outlet pressure of the condenser 52 and is adiabatically expanded by the expansion valve 54 to lower the refrigerant pressure to the point L below the critical pressure (about 30 kgf / cm ² G). Next, the refrigerant flows into the cooler 53, and the refrigerant in the cooler 53 evaporates by removing surrounding heat and returns to the rotary compressor 50.

Next, the refrigerant circuit of the two-cylinder rotary compressor 1 described in detail with reference to FIG. 1 will be described with reference to FIGS.

In the case of the two-cylinder rotary compressor 1,
A lower outlet pipe 31 provided in the lower cylinder 15 of the rotary compressor 1 and a condenser 37 are connected via a discharge-side refrigerant pipe 32, and the condenser 37 and the cooler 38 are expanded. The refrigerant pipe 40 is connected via a valve 39. The cooler 38 and the upper cylinder 14 of the rotary compressor 1
The upper inlet pipe is connected to the suction side refrigerant pipe 33.

The refrigerant pipe 40 connecting the condenser 37 and the expansion valve 39 is provided with a bypass pipe 43 connected to a subcooler 42 via a bypass expansion valve 41.

The supercooler refrigerant pipe 44 from the subcooler 42 is connected to an upper outlet pipe 30 provided in the upper cylinder 14 of the rotary compressor 1 and a lower inlet pipe 29 of the lower cylinder 15.
And a connection refrigerant pipe 34 for connecting the inside and the inside of the suction muffler 36.

Incidentally, the subcooler 42 is constituted by a double pipe, in which the refrigerant from the bypass pipe 43 flows inside, and the refrigerant in the refrigerant pipe 40 flows outside. Conversely, the inside may be the refrigerant pipe 40 and the outside may be the bypass pipe 43.

Further, a structure provided in contact with heat conduction may be used.

The refrigerant pipe 40 branching off from the bypass pipe 43 is introduced into the subcooler 42, where it contacts the bypass pipe 43 after the bypass expansion valve 41 in a heat conductive manner. It is provided. Thereafter, it is connected to the expansion valve 39 described above.

Therefore, the gas refrigerant of carbon dioxide, which has been compressed by the two-cylinder rotary compressor 1 and has become high temperature, is cooled by the condenser 37, and is further cooled by the subcooler 42 to the heat of the bypass pipe 43. After the replacement, that is, the heat is released, the expansion valve 39 expands. Thereafter, the gas refrigerant flowing into the cooler 38 and radiating heat here returns to the rotary compressor 1 again from the suction side refrigerant pipe 33.

A part of the refrigerant condensed in the condenser 37 is diverted to the bypass pipe 43 and is adiabatically expanded by the bypass expansion valve 41.
From the heat. The refrigerant collected in the supercooler 42 is mixed with the high-temperature, high-pressure refrigerant in the upper cylinder 14,
The high-temperature, high-pressure refrigerant is cooled and flows into the lower cylinder 15. In addition, the refrigerant after collecting heat in the supercooler 42 is:
The high temperature after the discharge of the upper cylinder 14 is lower than the high pressure refrigerant.

In FIG. 5, point A is the refrigerant discharged from the supercooler 42 and the compressor upper cylinder 14 and merged into the lower cylinder 15, and point B is the refrigerant discharged from the lower cylinder 15. is there. In this state, the refrigerant is kept at the same pressure and lower in temperature than in the case of one cylinder.

Then, the refrigerant at point C is condensed in the condenser 37 and then agitated, and is adiabatically expanded by the bypass expansion valve 41. The point D is adiabatically expanded and pressure-reduced refrigerant that has radiated heat, flows into the supercooler 42, and cools the refrigerant at the point C to the point E.

Further, the supercooled refrigerant at the point E is adiabatically expanded by the expansion valve 39 to be in the state at the point F. Thereafter, as indicated by point G, the refrigerant that has collected heat in the cooler 38 and has become high temperature flows into the upper cylinder 14.

As shown at point H, the refrigerant which has been compressed by the upper cylinder 14 and has become high temperature and high pressure is supplied to the above-described subcooler 4.
2, the pressure decreases, the refrigerant is used for supercooling, and merges with the refrigerant whose temperature has risen (however, as described above, the high temperature after discharge of the upper cylinder 14 and the lower temperature than the high-pressure refrigerant). The cooled refrigerant flows into the rotary compressor 1.

The carbon dioxide compressed by the rotary compression element 5 has a low critical point temperature, usually about 31 ° C. Therefore, when carbon dioxide is used as a refrigerant, the refrigerant is used in a gasified state, that is, in a supercritical region. In the supercritical region, the carbon dioxide refrigerant has a high pressure and a high vapor density. Therefore, in a compressor having an internal high pressure, there is a problem that a load is applied to the closed vessel 2. However, a rotary compressor having an internal low pressure or an internal intermediate pressure is used. The use of the refrigerants 1 and 50 makes it possible to exhibit the same refrigerating capacity as other refrigerants without imposing an unnecessary load on the closed casing 2 of the rotary compressors 1 and 50.

Therefore, even if the inside of the closed vessel 2 is set at a low pressure similar to the suction pressure of the refrigerant, it has the same refrigerating capacity as other refrigerants, and is a rotary type using small and inexpensive carbon dioxide as the refrigerant. Compressors 1 and 50 can be provided.

Here, in order to reduce the pressure inside the sealed container 2, the refrigerant sucked from the compressor may be introduced into the sealed container 2. For example, the two-cylinder rotary compressor 1 of the present embodiment may be used.
In this case, the introduction pipe of the upper cylinder 14 may be opened in the closed vessel 2 to introduce a part of the refrigerant. This makes it possible to make the internal pressure of the closed vessel 2 substantially the same as the suction refrigerant, that is, a low pressure.

The critical pressure of the carbon dioxide refrigerant is about 72
A ~73kgf / cm ² G, the critical pressure or higher, that is, in a supercritical range, the carbon dioxide refrigerant are those gasified.

Further, even if the inside of the closed container 2 is set at an intermediate pressure higher than the suction pressure of the refrigerant and lower than the discharge pressure (for example, the suction pressure of the second stage in the case of two-stage compression), the same as other refrigerants is used. It is possible to provide the rotary compressors 1 and 50 having a refrigerating capacity and using small and low-cost carbon dioxide as a refrigerant.

Here, in order to set the inside of the closed vessel 2 to an intermediate pressure, a part of the refrigerant being compressed may be introduced into the inside of the closed vessel 2. In the case of the machine 1, the introduction pipe of the lower cylinder 15 may be opened in the closed vessel 2 to introduce a part of the refrigerant. This makes it possible to make the internal pressure of the closed vessel 2 substantially equal to the refrigerant pressure after the primary compression by the upper cylinder 14, that is, the intermediate pressure.

Further, by performing a plurality of stages of compression, the temperature of the gas discharged from the rotary compressor 1 can be kept low. Accordingly, the heat resistance of the rotary compressor 1 can be improved, and the deterioration of the carbon dioxide refrigerant itself and the lubricating oil can be prevented, so that the reliability of the rotary compressor 1 can be improved.

In the above description, especially in the case of the rotary compressor 1 having two cylinders, the rotary compressor 1 having an internal low pressure is defined as (pressure in the sealed container 2) <(upper cylinder 14).
(The average pressure of the compression space of the lower cylinder 15) <(the average pressure of the compression space of the lower cylinder 15).
The rotary compressor 1 having the internal intermediate pressure is defined as (upper cylinder 1
4 (average pressure in compression space) <(pressure in closed container 2) <
(The average pressure of the compression space of the lower cylinder 15).

The rotary compressors 1 and 50 described in detail above
And refrigeration circuits using the rotary compressors 1 and 50 are used for home air conditioners, commercial air conditioners (package air conditioners),
It is used for automotive air conditioners, home refrigerators, commercial refrigerators, commercial freezers, commercial refrigerators, showcases, vending machines, water heaters and the like.

Further, the rotary compressors 1 and 50
It is the size of the frame, which is one horsepower output.

[0065]

As described in detail above, according to the first aspect of the present invention, since carbon dioxide is used as the refrigerant and the internal pressure is reduced, the refrigerant has the same refrigerating capacity as other refrigerants, and is small in size and low in cost. It is possible to provide a rotary compressor using carbon dioxide as a refrigerant.

According to the second aspect of the present invention, since carbon dioxide is used as the refrigerant and the internal intermediate pressure is used, the refrigerant has the same refrigerating capacity as other refrigerants, and can reduce the size of the carbon dioxide which is small and inexpensive. Can be provided.

According to the third aspect of the present invention, the temperature of the discharge gas of the rotary compressor can be kept low by performing the multiple-stage compression. Therefore, the heat resistance of the rotary compressor can be improved, the deterioration of the carbon dioxide refrigerant itself and the lubricating oil can be prevented, and the reliability of the rotary compressor can be improved.

According to the fourth aspect of the invention, compression is performed in a plurality of stages, the refrigerant before entering the expansion valve is cooled by the supercooler, and the discharge gas temperature of the rotary compressor is reduced by the subcooler. At the same time, the heat resistance of the rotary compressor can be improved, and the carbon dioxide refrigerant itself and the lubricating oil can be prevented from being deteriorated, so that the reliability of the rotary compressor can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a two-cylinder rotary compressor equipped with the present invention.

FIG. 2 is a refrigeration circuit diagram using a one-cylinder rotary compressor equipped with the present invention.

FIG. 3 is a Mollier diagram in a refrigeration circuit diagram using a one-cylinder rotary compressor equipped with the present invention.

FIG. 4 is a refrigeration circuit diagram using a two-cylinder rotary compressor equipped with the present invention.

FIG. 5 is a Mollier diagram in a refrigeration circuit diagram using a two-cylinder rotary compressor equipped with the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 2 cylinder rotary compressor 2 airtight container 3 electric element 5 rotary compression element 14 upper cylinder 15 lower cylinder 18 upper roller 19 lower roller 20 upper vane 21 lower vane 22 main frame 23 bearing plate 42 subcooler 50 1 cylinder Rotary compressor

Continued on the front page (72) Inventor Nobuo Komoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Masaya Tadano 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 F-term in Sanyo Electric Co., Ltd. (reference) 3H029 AA04 AA09 AA13 AA17 AB03 AB05 BB00 BB11 BB12 BB38 BB44 CC09 CC22 CC24 CC46

Claims (4)

[Claims] 1. A rotary compression element comprising a cylinder whose both ends are closed, a roller rotating in the cylinder, and a vane forming a compression space in the cylinder by contacting the roller. A rotary compressor that compresses the sucked refrigerant by the rotary compression element and discharges the compressed refrigerant, wherein carbon dioxide is used as the refrigerant and the pressure inside the sealed container is reduced. . 2. A rotary compression element comprising a cylinder whose both ends are closed, a roller rotating in the cylinder, and a vane forming a compression space in the cylinder by contacting the roller. A rotary compressor that compresses the sucked refrigerant by the rotary compression element and discharges the compressed refrigerant, wherein carbon dioxide is used as the refrigerant and the inside of the sealed container is set to an intermediate pressure. Machine. 3. The rotary compressor according to claim 1, wherein the rotary compression element has a plurality of stages. 4. A refrigeration circuit comprising the rotary compressor according to claim 3, further comprising a supercooler for lowering the temperature of refrigerant discharged from the rotary compressor.