KR100620043B1 - Capacity variable type rotary compressor and airconditioner with this - Google Patents

Abstract

A variable displacement double rotary compressor according to the present invention and an air conditioner including the same include: a plurality of cylinders; An upper bearing plate covering the upper cylinder; An intermediate bearing plate interposed between the upper cylinder and the lower cylinder; The lower cylinder is covered to form the inner space of the lower cylinder together, and a plurality of bypass holes are formed to communicate the compression chamber and the suction chamber with the vanes as the center, and one valve hole is formed so that the plurality of bypass holes communicate with each other. A lower bearing plate forming a communication hole so that the valve hole communicates with the inner space of the casing; A valve unit which slides into the valve hole of the lower bearing plate to block the bypass hole during normal operation while opening the bypass hole during idling to bypass the refrigerant in the compression chamber to the suction chamber; And a back pressure switching unit for differentially supplying pressure to one side of the valve unit to open and close the bypass hole according to the operation mode, thereby increasing the refrigeration capacity reduction rate during the saving operation of the compressor as well as operating the air conditioner. Can be adjusted in various ways, reducing unnecessary power consumption of the compressor and the air conditioner employing the same. In addition, it can be widely applied to a compressor or air conditioner having a frequent refrigeration capacity control function, it is possible to prevent a decrease in efficiency of the compressor or air conditioner employing the same.

Description

CAPACITY VARIABLE TYPE ROTARY COMPRESSOR AND AIRCONDITIONER WITH THIS}

1 is a system diagram showing an example of a conventional variable displacement rotary compressor,

2a and 2b is a plan view showing a compression chamber during normal operation and saving operation in the conventional variable displacement rotary compressor,

3 is a schematic diagram of an air conditioner having a variable displacement double rotary compressor according to the present invention;

4 is a longitudinal sectional view showing an example of the present invention of a variable displacement double type rotary compressor;

5 is a cross-sectional view of the valve unit of the variable displacement double rotary compressor of the present invention in a transverse direction showing it;

6a and 6b is an operation showing the normal operation and saving operation in the variable displacement double rotary compressor of the present invention,

7 is a schematic view showing a variable operation of the present invention variable displacement double type rotary compressor.

** Description of symbols for the main parts of the drawing **

1: Casing 10: First Compressor Part

20: 2nd compression mechanism part 11, 21: 1st, 2nd cylinder

11a, 21a: 1st, 2nd vane slot 12: main bearing

12a: first discharge port 13: middle bearing

13a: 2nd discharge port 14,23: 1st, 2nd rolling piston

15,24: 1st, 2nd vane 16, 25: 1st, 2nd discharge valve

17: muffler 22b, 22c: bypass hole

22d: bearing hole 22e: communication hole

30: valve unit 31: sliding valve

32: valve spring 40: back pressure switching unit

41: switching valve assembly 42: high pressure connector

43: low pressure connector 44: common connector

SP1, SP2: 1st and 2nd gas suction pipe DP: Gasoline discharge pipe

The present invention relates to a variable displacement double rotary compressor and an air conditioner using the same, and more particularly, to a variable displacement double rotary compressor capable of varying a capacity using a leakage passage and an air conditioner using the same.

In general, a rotary compressor is mainly applied to an air conditioner such as an air conditioner. Recently, as the function of the air conditioner is diversified, the rotary compressor also requires a product that can vary in capacity. As a technique for varying the capacity of a rotary compressor, a so-called inverter method for controlling the number of revolutions of the compressor by using an inverter motor is mainly known, but this technique is expensive because the inverter motor itself is expensive, and most of the statistics are statistically significant. Considering that air conditioners are used as air conditioners, it is difficult to increase the refrigerating capacity under cooling conditions, which is more important in air condition compressors, rather than to increase the refrigerating capacity under heating conditions.

Accordingly, in recent years, the so-called "refrigeration capacity change technology" by changing the volume of the compression chamber by bypassing part of the refrigerant gas compressed in the cylinder to the outside of the cylinder (hereinafter referred to as "exchange volume switching"). Abbreviated as technology) is widely known.

1 is a system diagram showing an example of a conventional variable displacement rotary compressor, Figures 2a and 2b is a schematic diagram showing the compression chamber area for the normal operation and the saving operation of the conventional variable displacement rotary compressor.

As shown in the drawing, the conventional variable displacement rotary compressor forms a bypass hole 1a of the cylinder so that a part of the refrigerant compressed in the middle of the compression space of the cylinder 1 can be bypassed according to the operation state of the compressor. The bypass pipe P1 is connected to the bypass hole 1a to the outside of the casing 2, and is piped from the end of the bypass pipe P1, and one end thereof is discharged from the casing 2 and the condenser ( 3) is connected to the discharge side connecting pipe (P3) in the middle of the gas discharge pipe (P2) for connecting while the other end is the suction side connecting pipe in the middle of the gas suction pipe (P4) connecting the evaporator (5) and the accumulator (6) It is connected to (P5). In addition, a discharge side valve V1 and a suction side valve V2 are respectively provided in the middle of the discharge side connecting pipe P3 and the suction side connecting pipe P5, and at the inlet side end of the bypass pipe P1. The bypass valve V3 is provided to open and close the bypass hole 1a of the cylinder 1 in accordance with the opening and closing of the discharge side valve V1 and the suction side valve V2.

In the drawings, reference numeral 4 denotes an expansion mechanism, 6 a rotation shaft, 7 a rolling piston, and 8 a vane.

When the compressor operates normally in the conventional variable displacement rotary compressor as described above, a part of the refrigerant discharged to the gas discharge pipe P2 is discharged as the discharge valve V1 of FIG. 1 is opened and the suction valve V2 is closed. Flowing into the bypass pipe P1 along the solid arrow, the refrigerant at the discharge pressure Pd pushes the bypass valve V3 as shown in FIG. 2A to block the bypass hole 1a of the cylinder 1. As a result, a series of processes of discharging all the refrigerant sucked into the compression space of the cylinder 1 into the gas discharge pipe P2 discharged while being compressed are repeated.

On the other hand, when the compressor performs the saving operation, as the discharge valve V1 of FIG. 1 is closed and the suction valve V2 is opened, the pressure back surface of the bypass valve V3 becomes the suction pressure Ps environment, and FIG. 2B. As shown in FIG. 1, the bypass valve V3 is pushed to open the bypass hole 1a, and a part of the refrigerant compressed in the compression space through the open bypass hole 1a is connected to the suction side connection pipe along the dotted arrow of FIG. 1. Bypassing to the accumulator 6 through P5, a suction delay occurs, and only a part of the refrigerant sucked into the compression space of the cylinder 1 is compressed and discharged.

However, the variable capacity device of the conventional rotary compressor as described above is provided with a bypass circuit separately on the side of the cylinder (1), the resistance is increased when the refrigerant is bypassed during the saving operation, the refrigeration capacity reduction rate is small and the efficiency is lowered There was a problem.

In addition, as the bypass pipe P2, the discharge side connecting pipe P3, and the suction side connecting pipe P5 are installed outside the compressor casing 2 and connected to the air conditioning pipe, it is difficult to assemble the air conditioning pipe. In addition, since the discharge side valve (V1) and the suction side valve (V2) must be separately installed in the pipe, there is a problem in that the number of parts increases and the cost increases.

The present invention has been made in view of the problems of the conventional variable capacity of the rotary compressor as described above, to provide a variable capacity rotary compressor and an air conditioner applied to the variable capacity to increase the efficiency of the refrigeration capacity reduction rate during the saving operation. There is a purpose.

Another object of the present invention is to provide a variable displacement rotary compressor capable of easily and simply configuring a variable capacity device of a compressor and reducing production costs by reducing the number of parts.

In order to achieve the object of the present invention, the rolling piston is formed in the inner space in the center to suck and compress the refrigerant while the pivoting movement, respectively, the inlet is formed to communicate with the gas suction pipe in the inner space, the radius in the rolling piston A plurality of cylinders each formed in a vane slot to support vanes for partitioning the internal space into a compression chamber and a suction chamber in contact with each other in a direction to be fixed up and down along the axial direction; An upper bearing plate covering the upper cylinder to form an inner space of the upper cylinder, and forming a discharge port to communicate with the compression chamber of the upper cylinder and discharge the compressed refrigerant; An intermediate bearing plate interposed between the upper cylinder and the lower cylinder to form an inner space of the upper cylinder and the lower cylinder; The lower cylinder is covered to form the inner space of the lower cylinder together, and a plurality of bypass holes are formed to communicate the compression chamber and the suction chamber with the vanes as the center, and one valve hole is formed so that the plurality of bypass holes communicate with each other. A lower bearing plate forming a communication hole so that the valve hole communicates with the inner space of the casing; A valve unit which slides into the valve hole of the lower bearing plate to block the bypass hole during normal operation while opening the bypass hole during idling to bypass the refrigerant in the compression chamber to the suction chamber; It provides a variable displacement double rotary compressor comprising a; back pressure switching unit for differentially supplying pressure to one side of the valve unit to open and close the bypass hole according to the operation mode.

In addition, in the air conditioner including a compressor including a plurality of cylinders, a condenser, an expansion mechanism, and an evaporator, an inner space is respectively formed at the center thereof so that the rolling piston sucks and compresses the refrigerant during the pivoting movement. Inlet ports are formed to communicate with the gas suction pipes in the space, and vane slots are formed in the casing to support the vanes partitioning the inner space into the compression chamber and the suction chamber by radially contacting the rolling piston. A plurality of cylinders fixed to each other; An upper bearing plate which covers the upper cylinder to form an inner space of the upper cylinder and forms a discharge port to discharge the refrigerant compressed through the compression chamber of the upper cylinder; An intermediate bearing plate interposed between the upper cylinder and the lower cylinder to form an inner space of the upper cylinder and the lower cylinder; The lower cylinder is covered to form the inner space of the lower cylinder together, and a plurality of bypass holes are formed to communicate the compression chamber and the suction chamber with the vanes as the center, and one valve hole is formed so that the plurality of bypass holes communicate with each other. A lower bearing plate forming a communication hole so that the valve hole communicates with the inner space of the casing; If the room temperature is out of the set temperature range by inserting it slippery into the valve hole of the lower bearing plate, the bypass hole is shut off for normal operation. If the room temperature is within the set temperature range, the bypass hole is A valve unit which opens to bypass the refrigerant in the compression chamber to the suction chamber to idle; Provides an air conditioner comprising a; back pressure switching unit for differentially supplying pressure to one side of the valve unit to open and close the bypass hole in accordance with the difference between the room temperature and the set temperature.

Hereinafter, a variable displacement double rotary compressor according to the present invention and an air conditioner using the same will be described in detail with reference to an embodiment shown in the accompanying drawings.

Figure 3 is a schematic diagram of an air conditioner having a variable displacement double rotary compressor of the present invention, Figure 4 is a longitudinal sectional view showing an example of the variable displacement double rotary compressor of the present invention, Figure 5 is a valve unit of the variable displacement double rotary compressor of the present invention. 6A and 6B are sectional views showing normal operation and saving operation in the variable displacement double type rotary compressor of the present invention, and FIG. 7 shows the variable operation of the variable displacement double rotary compressor of the present invention. Schematic diagram.

As shown in the drawing, the double rotary compressor according to the present invention is provided with a casing (1) for communicating gas suction pipe (SP) and gas discharge pipe (DP), and an electric motor that is installed above the casing (1) to generate rotational force. On the side of the first compression mechanism portion 10 and the second compression mechanism portion 20 and the second compression unit 20, which is installed under the mechanism portion, the casing 1 and compresses the refrigerant by the rotational force generated in the electric mechanism portion. And a back pressure switching unit 40 connected to the valve unit 30 to vary the capacity of the compression chamber and the valve unit 30 to operate the valve unit 30 by the pressure difference according to the operation mode of the compressor. Include.

The electric drive unit rotates while interacting with the stator Ms by fixing the inside of the casing 1 to stator Ms for applying power from the outside, and having a predetermined gap inside the stator Ms. It consists of an electron (Mr) and a rotating shaft (C) which is coupled to the rotor (Mr) and transmits a rotational force to the compression mechanism.

As shown in FIG. 4, the first compression mechanism part 10 covers the first cylinder 11 installed in the casing 1 and the upper and lower sides of the first cylinder 11 to cover the first interior. The first bearing of the first cylinder 11 is rotatably coupled to the main bearing 12 and the middle bearing 13 which radially support the rotating shaft while forming the space V1, and the upper eccentric portion of the rotating shaft 3. The first rolling piston 14 which compresses the refrigerant while turning in the first internal space V1 and the first cylinder 11 are movably coupled radially so as to be pressed against the outer circumferential surface of the first rolling piston 14. A first vane 15 for dividing the first inner space V1 of the first cylinder 11 into a first suction chamber and a first compression chamber, and a first discharge port provided near the center of the main bearing 12 ( 12a) a first discharge valve 16 coupled to the front end so as to be openable and closed to control the discharge of the refrigerant gas discharged from the first compression chamber, It is composed of a muffler (17) for receiving the first discharge valve 16 is coupled to the main bearing (12).

The second compression mechanism 20 is formed in an annular shape as shown in Fig. 4, the second cylinder 21 to be installed below the first cylinder 11 inside the casing 1, and both the upper and lower sides of the second cylinder 21 The middle bearing 13 and the sub-bearing 22 and the lower eccentric part of the rotating shaft 3 which support the said rotating shaft 3 in the radial direction and the axial direction while forming the 2nd inner space V1 together, The second cylinder to be in contact with the outer peripheral surface of the second rolling piston 23 and the second rolling piston 23 to compress the refrigerant while turning in the second inner space (V2) of the second cylinder 21 rotatably coupled A second vane 24 and a middle bearing, which are movably coupled to the 21 to partition the second inner space V2 of the second cylinder 21 into a second suction chamber and a second compression chamber, respectively, 13 is coupled to the front end of the second discharge port 13a provided to control the discharge of the refrigerant gas discharged from the second compression chamber. It consists of the 2nd discharge valve 25.

The second cylinder 21 is formed in an annular shape so that the second rolling piston 23 can perform a relative movement, and at one side thereof, the second vane 24 can perform a linear movement in the radial direction. The second vane slot 21a is linearly formed, and a second suction port 21b communicating with the second gas suction pipe SP2 is radially penetrated at one side of the second vane slot 21a, and the middle bearing 13 is formed. At the other upper edge of the second vane slot 21a in contact with the second vane slot 21a, the refrigerant compressed in communication with the second discharge port 13a of the middle bearing 13 is discharged regardless of the trajectory of the second rolling piston 23. A second discharge guide groove (unsigned) is formed to be smoothly discharged to 13a, and idling is communicated with the bypass holes 22b and 22c which will be described later at lower left and right sides of the second vane slot 21a. Coolant is leaked from the second compression chamber to the second suction chamber irrespective of the trajectory of the second rolling piston 23. It made to form the lock by-pass the guide groove (21c).

Here, the second discharge port 13a is formed in the middle bearing 13 so as not to overlap with the bypass holes 22b and 22c of the sub bearing 22, which will be described later. It is preferable to form in an empty hollow shape. In this case, the first discharge port may be formed in the middle bearing instead of the main bearing.

The sub-bearing 22 has a bearing hole 22a for radially supporting the rotation shaft C at the center thereof, and is formed in a disc shape, and the sub bearing 22 is formed on the basis of the vane slot 21a of the second cylinder 21. On the left and right sides of the two vane slots 21a, a plurality of bypass holes 22b and 22c are formed so as to correspond to the bypass guide grooves 21c of the second cylinder 21, and a plurality of bypass holes ( Two bypass holes 22b and 22c are accommodated so that 22b and 22c communicate with each other to form a valve hole 22d so as to be negatively shaped to a predetermined depth in the radial direction, and one side of the valve hole 22d is provided with a casing ( The communication hole 22e is formed so as to communicate with the internal space of 1) to pressurize one side pressure portion of the sliding valve 31 to be described later.

The bypass holes 22b and 22c are formed to be inclined in a direction substantially coincident with or in contact with each other, but the diameter thereof is preferably formed to be wider than an interval of the communication portion 31c of the sliding valve 31 which will be described later. In addition, the diameter of the communication hole 22e is preferably formed so that the oil of the casing 1 can flow into the valve hole 22d.

As shown in FIGS. 4 and 5, the valve unit 30 slides into the valve hole 22d and moves in the valve hole 22d according to the pressure difference by the back pressure switching unit 40. The sliding valve 31 which opens and closes the bypass holes 22b and 22c together and elastically supports the moving direction of the sliding valve 31 to the position where the sliding valve 31 closes when the pressure difference between both ends is the same. It consists of a valve spring 32 of compression spring to move.

The sliding valve 31 is formed to be in sliding contact with the inner circumferential surface of the valve hole 22d, and receives the pressure from the inner space of the casing 1 to close the two bypass holes 22b and 22c. Between the second pressure part 31b and the two pressure parts 31a and 31b which are formed to be in sliding contact with the inner circumferential surface of the valve hole 22d and receive pressure from the back pressure switching unit 40 described above. And a communication portion 31c in which a gas passage is formed so that the two bypass holes 22b and 22c communicate between the outer peripheral surface and the valve hole 22d.

The first pressure portion 31a is formed to be longer than the diameters of both bypass holes 22b and 22c, and the rear end thereof has a communication valve 22e while the sliding valve 31 is always spaced from the inner side of the valve hole 22d. It is preferable to form the support protrusions 31d so that always open).

The communication part 31c is formed smaller than the diameter of both pressure parts 31a and 31b, and the length is formed shorter than the diameter of the bypass hole 22b and 22c.

The back pressure switching unit 40 casings the switching valve assembly 41 and the switching valve assembly 41 which determine the pressure of the second pressure side of the sliding valve 31 as shown in FIGS. 3 and 6A and 6B. 1) a high pressure connecting pipe 42 for supplying a high pressure atmosphere by connecting to 1), a low pressure connecting pipe 43 for supplying a low pressure atmosphere by connecting the switching valve assembly 41 to the outlet side of the accumulator 6, and a switching valve. The assembly 41 is connected to the second pressure portion side of the valve hole 22d to form a common connecting pipe 44 for selectively supplying a high pressure atmosphere or a low pressure atmosphere to the second pressure portion 31b of the sliding valve 31. .

The inlet end of the high-pressure connecting pipe 42 may be connected to the middle of the gas discharge pipe DP. However, in some cases, the inlet end of the high pressure connecting pipe 42 is connected to the lower half of the casing 1 so as to be immersed in the oil filled in the casing 1. Oil may flow between the valve hole 22d and the sliding valve 31 to block friction loss or gas leakage.

In the drawings, reference numeral 3 denotes a condenser, 4 an expansion mechanism, and 5 an evaporator.

The present invention of the variable displacement double rotary compressor of the present invention operates as follows.

That is, when the electric power is applied to the electric drive unit, the rotating shaft C rotates, and each of the rolling pistons 14 and 23 rotates the respective inner spaces V1 of the first cylinder 11 and the second cylinder 21 ( While making a pivoting movement in V2), a volume is formed between the first vane 15 and the second vane 24 to suck and compress the refrigerant, and then discharge the refrigerant into the casing 1. Through the pipe (DP) to the condenser (2) of the refrigeration cycle device, and after passing through the expansion mechanism (3) and the evaporator (4) in turn through the respective gas suction pipe (SP1) SP2 and the first cylinder (11) ) And a series of processes to be sucked into the inner space (V1) (V2) of the second cylinder (21).

In this case, when the compressor is in normal operation (power operation), the power is turned off to the back pressure switching unit 40, which is a pilot valve, as shown in FIG. 6A, so that the high pressure connecting pipe 42 and the common connecting pipe 44 are turned off. ) To communicate. Thus, during operation, the low pressure refrigerant gas passing through the second gas suction pipe SP2 or the evaporator 5 passes through the high pressure connecting pipe 42 and the common connecting pipe 44 to the second pressure part 31b of the sliding valve 31. ) To the side. At this time, the high pressure is supplied to the first pressure portion 31a of the sliding valve 31 through the communication hole 22e of the sub bearing 22 so that the pressures on both sides of the sliding valve 31 are the same, but the second pressure portion The sliding valve 31 is pushed toward the first pressure portion 31a by the elastic force of the valve spring 32 disposed on the 31b side, and the second pressure portions 31b are both bypass holes 22b and 22c. ) Will be blocked at the same time. In this way, the refrigerant gas compressed in the compression chamber of the second cylinder 21 passes through the second discharge port 13a of the middle bearing 13 as the bypass holes 22b and 22c are blocked. 100% while circulating through the condenser 2, the expansion mechanism 3, and the evaporator 4 after being discharged to the inside of the casing 1 together with the refrigerant discharged from the first cylinder, Compression operation to exercise the freezing capacity of.

On the other hand, when the compressor is idling (saving operation) as shown in Figure 6b to turn on the power (ON) to the back pressure switching unit 40, which is a pilot valve to connect the low-pressure connecting pipe 43 and the common connecting pipe 44 Connect it. Thus, during operation, the force due to the pressure on the first pressure part 31a side is greater than the sum of the pressure on the side of the second pressure part 31b and the elastic force of the valve spring 32 so that the sliding valve 31 receives the second pressure. Bypass holes 22b and 22c are opened while moving toward the portion 31b side. In this way, the refrigerant compressed in the compression chamber of the second cylinder 21 leaks from the compression chamber side bypass hole 22c to the suction chamber side bypass hole 22b. The refrigeration capacity is zero (0) non-compression operation, thereby exhibiting only the freezing capacity of the first compression mechanism (10) (for example, approximately 60% if the capacity of the first compression portion and the second compression mechanism is 60:40). It is a saving driving.

On the other hand, when the variable capacity double type rotary compressor according to the present invention is applied to the air conditioner, look at the effect of taking the cooling operation as an example as follows.

In other words, if the room temperature is higher than the set temperature by comparing the room temperature with the set temperature, the compressor performs the normal operation described above to allow the air conditioner to exhibit 100% cooling capacity while the room temperature is lower than or equal to the set temperature. In this case, the second compression mechanism performs the idling described above, so that the second compression mechanism does not work, so that only the capacity of the first compression mechanism is used.

In addition, the air conditioning capacity range can be widely varied by adjusting the normal operation and the saving operation time as necessary. For example, in the case of controlling the capacity at 10% as shown in FIG. 7, assuming that the total operation time is 20 seconds, the normal operation is performed for 2 seconds while the saving operation is performed for 18 seconds, and the capacity is 50%. In case of control, normal operation and saving operation are performed alternately every 10 seconds when the total operation time is 20 seconds.In case of controlling the capacity at 90%, normal operation is performed for 10 seconds when the total operation time is 20 seconds. By performing the saving operation for 2 seconds, it is possible to further control the refrigeration capacity of the compressor and the air conditioner. Through this, it is possible to supply rotary compressors and air conditioners with high efficiency and high reliability while significantly lowering costs compared to inverter rotary compressors.

The variable displacement double rotary compressor according to the present invention and the air conditioner using the same form a bypass hole communicating the compression chamber and the suction chamber of the cylinder with vanes in the second sub-bearing, and the bypass hole is formed by a pressure difference. By opening and closing the sliding valve to vary the capacity of the second compression mechanism, the flow resistance of the refrigerant can be reduced to increase the freezing capacity reduction rate during volume exclusion operation, and to control the refrigeration capacity of the air conditioner by adjusting the operation time between modes. By diversifying, unnecessary power consumption of the compressor and the air conditioner employing the same can be reduced and efficiency can be increased.

Claims (11)

While the rolling piston is pivoting, the inner space is formed at the center to suck and compress the refrigerant, and the suction ports are respectively formed at the inner space to communicate with the gas suction pipe, and the rolling piston is radially contacted to compress the inner space. A plurality of cylinders each formed with vane slots to support vanes partitioned into a seal and a suction chamber, and fixedly installed vertically in the casing in an axial direction; An upper bearing plate covering the upper cylinder to form an inner space of the upper cylinder, and forming a discharge port to communicate with the compression chamber of the upper cylinder and discharge the compressed refrigerant; An intermediate bearing plate interposed between the upper cylinder and the lower cylinder to form an inner space of the upper cylinder and the lower cylinder; The lower cylinder is covered to form the inner space of the lower cylinder together, and a plurality of bypass holes are formed to communicate the compression chamber and the suction chamber with the vanes as the center, and one valve hole is formed so that the plurality of bypass holes communicate with each other. A lower bearing plate forming a communication hole so that the valve hole communicates with the inner space of the casing; A valve unit which slides into the valve hole of the lower bearing plate to block the bypass hole during normal operation while opening the bypass hole during idling to bypass the refrigerant in the compression chamber to the suction chamber; And a back pressure switching unit for differentially supplying pressure to one side of the valve unit so that the valve unit opens and closes the bypass hole in accordance with the operation mode. The method of claim 1, And a bypass guide groove formed on the inner circumferential surface of the lower cylinder so as to communicate with the bypass hole of the lower bearing plate at both sides of the vane slot. The method of claim 1, And a plurality of bypass holes are formed on substantially the same circumference, and one valve hole is formed radially so as to form a normal line on the circumference connecting the center of the bypass hole. The method of claim 3, The valve unit is slidably inserted into the valve hole, and the sliding valve for simultaneously opening and closing the plurality of bypass holes while moving radially from the valve hole according to the pressure difference by the back pressure switching unit, and the movement direction of the sliding valve elastically A variable displacement double rotary compressor, comprising: a valve spring for supporting and moving the sliding valve to an open position when the pressure difference between both ends is the same. The method of claim 4, wherein The sliding valve is formed on both sides of the bypass hole to be in sliding contact with the inner circumferential surface of the valve hole, and one side thereof receives the pressure inside the casing through the communication hole while the other side moves under the pressure of the back pressure switching unit. A plurality of pressure parts formed to open and close the bypass hole, and a communication part connecting the plurality of pressure parts and a gas passage formed to communicate the plurality of bypass holes between the outer peripheral surface and the valve hole. Variable speed double rotary compressor. The method of claim 5, And a sliding valve maintains a predetermined distance between the sliding valve and the valve hole to form a supporting protrusion so that the communication hole is always opened. The method of claim 1, The back pressure switching unit is connected to a switching valve assembly for determining the pressure supplied to one side of the valve unit, a high pressure connecting pipe connected to the high pressure side inlet of the switching valve assembly to supply a high pressure atmosphere, and a low pressure side inlet of the switching valve assembly. A variable capacity double rotary compressor comprising a low pressure connection pipe for supplying a low pressure atmosphere and a common connection pipe for supplying a high pressure atmosphere or a low pressure atmosphere to one side of the valve unit by connecting the common outlet of the switching valve assembly to the valve hole. . The method of claim 7, wherein The switching valve assembly has a switching valve housing which forms the high pressure side inlet, the low pressure side inlet, and the common outlet, and is slidably coupled to the inside of the switching valve housing to be common with the high pressure side inlet, the common side outlet or the low pressure side inlet. A switching valve for selectively connecting the side outlet, an electromagnet installed on one side of the switching valve housing to move the switching valve by an applied power supply, and an elastic to restore the switching valve when the power applied to the electromagnet is cut off. A variable displacement double rotary compressor comprising a member. The method of claim 7, wherein The high-pressure connecting tube is a variable displacement double rotary compressor, characterized in that connected to the middle of the gas discharge pipe installed in communication with the inner space of the casing. The method of claim 7, wherein A variable displacement double rotary compressor characterized in that it is connected to the lower half of the casing so as to be immersed in the oil filling the inside of the casing. In an air conditioner including a compressor having a plurality of cylinders, a condenser, an expansion mechanism, and an evaporator, While the rolling piston is pivoting, the inner space is formed at the center to suck and compress the refrigerant, and the suction ports are respectively formed at the inner space to communicate with the gas suction pipe, and the rolling piston is radially contacted to compress the inner space. A plurality of cylinders each formed with vane slots to support vanes partitioned into a seal and a suction chamber, and fixedly installed vertically in the casing in an axial direction; An upper bearing plate covering the upper cylinder to form an inner space of the upper cylinder, and forming a discharge port to communicate with the compression chamber of the upper cylinder and discharge the compressed refrigerant; An intermediate bearing plate interposed between the upper cylinder and the lower cylinder to form an inner space of the upper cylinder and the lower cylinder; The lower cylinder is covered to form the inner space of the lower cylinder together, and a plurality of bypass holes are formed to communicate the compression chamber and the suction chamber with the vanes as the center, and one valve hole is formed so that the plurality of bypass holes communicate with each other. A lower bearing plate forming a communication hole so that the valve hole communicates with the inner space of the casing; If the room temperature is out of the set temperature range by inserting it slippery into the valve hole of the lower bearing plate, the bypass hole is shut off for normal operation. If the room temperature is within the set temperature range, the bypass hole is A valve unit which opens to bypass the refrigerant in the compression chamber to the suction chamber to idle; And a back pressure switching unit for differentially supplying pressure to one side of the valve unit so as to open and close the bypass hole according to a difference between the room temperature and the set temperature.

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