KR100619767B1 - Apparatus for changing capacity multi-stage rotary compressor - Google Patents

Abstract

The variable capacity device of the multi-stage rotary compressor of the present invention includes a first rolling piston having a first suction port and a first discharge port, and a first rolling piston which is pivoting and a first vane which is in linear contact with the first rolling piston. A second rolling piston having a first cylinder in which the suction chamber and the first compression chamber are partitioned, a second suction port and a second discharge port, and a second vane in linear motion in contact with the second rolling piston; A plurality of bypass holes inserted between the second cylinder divided by the second suction chamber and the second compression chamber and between the first cylinder and the second cylinder and communicating respective compression chambers of the first cylinder and the second cylinder with each other; And an intermediate bearing formed with a plurality of valve holes so as to communicate with the middle of the bypass hole, and slidingly coupled to the valve hole of the intermediate bearing to select the bypass hole. And a plurality of back pressure switching units for selectively supplying the discharge pressure to one side of the sliding valve and a plurality of sliding valves to be opened and closed by using the same. The effect is to achieve.

Variable capacity, multi-stage compressor, rotary compressor, pilot valve

Description

Capacity variable device of multi-stage rotary compressor {APPARATUS FOR CHANGING CAPACITY MULTI-STAGE ROTARY COMPRESSOR}

1 is a cross-sectional view showing an example of a conventional multi-stage rotary compressor,

2 is a sectional view showing a first embodiment of the present invention;

3 is an operation cross-sectional view showing a closed state of the bypass hole according to the first embodiment of the present invention;

4 is an operation cross-sectional view showing an open state of the bypass hole according to the first embodiment of the present invention;

5 is a schematic diagram for variable capacity according to a second embodiment of the present invention;

6 is a perspective view showing a part of the main part broken according to the second embodiment of the present invention;

7, 8 and 9 are cross-sectional views of operations according to the second embodiment of the present invention.

** Brief description of the main parts of the drawing **

1: casing 2: electric drive part

3: stator 4: rotor

5: axis of rotation 6: accumulator

7: condenser 8: expansion mechanism

9: expansion mechanism 10: first compression mechanism section

11: first cylinder 12: upper bearing

14: first rolling piston 15: first discharge valve

16: first discharge port 17: first suction port

19: first internal space 20: second compressor mechanism

21: second cylinder 22: lower bearing

23: second rolling piston 24: second discharge valve

26: second discharge port 27: second suction port

29: second internal space 30: the first gas suction pipe

31: second gas suction pipe 33: connector

40: gasoline tube 110: intermediate bearing

111 and 311: shaft hole 112: first valve hole

114: first bypass hole 116, 236, 237: valve stop

121: first sliding valve 123, 223, 233: locking projection

125, 135: Spring fixing end 131: Valve stopper

133: communication hole 141: valve spring

150: O-ring 160: first back pressure switching unit

162,212,222: high pressure side inlet 163,213,223: low pressure side inlet

164, 214, 224: common outlet 165: first switching valve housing

166: first switching valve 167, 217, 227: electromagnet

168: first switching spring 172: first high-pressure connector

173: first low pressure connector 174: first common connector

211: second switching valve unit 215: second switching valve housing

216: second switching valve 218: second switching spring

221: third switching valve unit 225: third switching valve housing

226: third switching valve 228: third switching spring

231: second sliding valve 232: third sliding valve

234: second bypass hole 235: third bypass hole

241: second switching spring 242: third switching spring

243: second valve hole 244: third valve hole

312: second high pressure connector 313: second low pressure connector

314: second common connector 322: third high-pressure connector

323: third low-pressure connector 324: third common connector

410: first vane 420: second vane

Compressors are widely used throughout the industry as devices for increasing pressure by receiving power from power generating devices such as electric motors and applying compression work to air, refrigerant, or other special gases. Compressors can be classified into volumetric and turbo type, depending on how the compression is achieved. Positive displacement compressors have a compression method that increases pressure through volume reduction, and a turbo compressor converts gas kinetic energy into pressure energy to achieve compression. Rotary compressors among volumetric compressors are mainly applied to air conditioners such as air conditioners, and in recent years, rotary compressors also require products that can vary in capacity in response to a trend of varying functions of air conditioners.

Rotary compressors have used CFC-based refrigerants until now. However, these refrigerants are regulated because they destroy the ozone layer and cause global warming, and research and development of alternative refrigerants instead of the existing refrigerants are actively performed. Carbon dioxide is expected as an alternative refrigerant. Moreover, the problem of global warming is not just a replacement for refrigerants, but also leads to a task of increasing the energy efficiency of equipment. This is because much of the electrical energy is still obtained using fossil fuels, because the carbon dioxide produced when burning fossil fuels is a major culprit of global warming.

In the compressor, which is the heart of the refrigeration system, the natural concern of colostrum is how to apply alternative refrigerants harmless to the global environment to existing compressors without any loss of performance.

There is a multi-stage rotary compressor having a plurality of compression units as a compressor that can vary in capacity and can use alternative refrigerants.

1 is a cross-sectional view showing an example of a conventional double rotary compressor.

As shown in the drawing, a conventional double rotary compressor includes a casing (1) for communicating two gas suction pipes (30) and (31) and a gas discharge pipe (40), and a rotational force provided above the casing (1). The rotating mechanism (5) is installed up and down under the casing (1) and the power mechanism part (2) consisting of the stator (3) and the rotor (4) so as to generate the rotational force generated on the rotating shaft (5). The first compressor mechanism 10 and the second compressor mechanism 20 for compressing the refrigerant, respectively.

In addition, an accumulator 6 for separating the liquid refrigerant from the suction refrigerant is provided between each of the gas suction pipes 30 and 31 and the compression mechanism units 10 and 20. The first gas suction pipe 30 is connected to the first suction port 17 to supply a refrigerant to the first cylinder 11, and the second gas suction pipe 31 is connected to the second suction port 27. The refrigerant is supplied to the second cylinder 21.

The first compression mechanism (10) is formed in an annular shape and installed in the casing (1) of the first cylinder (11), and the upper and lower sides of the first cylinder (11) together to cover the first internal space (19) The upper cylinder 12 and the intermediate bearing 13 for supporting the rotary shaft 5 in the radial and axial directions while being rotatably coupled to the upper eccentric portion of the rotary shaft 5 to be rotatably coupled to the first cylinder ( The first rolling piston 14 which compresses the refrigerant while turning in the first inner space 19 of 11) and moves radially to the first cylinder 11 so as to press-contact the outer circumferential surface of the first rolling piston 14. A first vane (not shown) which divides the first internal space 19 of the first cylinder 11 into a first suction chamber and a first compression chamber, and the first bearing provided in the upper bearing 12. A first opening and closing of the first discharge port 16 to control the discharge of the refrigerant gas discharged from the first compression chamber It includes an output valve 15.

The second compression mechanism 20 is formed in an annular shape to cover the second cylinder 21 installed below the first cylinder 11 inside the casing 1 and both the upper and lower sides of the second cylinder 21. The intermediate bearing 13 and the lower bearing 22 which support the rotating shaft 5 in the radial direction and the axial direction while forming the second inner space 29 together, and the lower eccentric portion of the rotating shaft 5 are rotatable. The second rolling piston 23 which compresses the refrigerant while turning in the second inner space 29 of the second cylinder 21 and compresses the outer circumferential surface of the second rolling piston 23. A second vane (not shown) coupled to the movable portion 21 in a radial direction and partitioning the second internal space 29 into a second suction chamber and a second compression chamber, and an agent provided in the lower bearing 22. 2 is connected to the discharging port 26 so as to be openable and closed to control the discharge of the refrigerant gas discharged from the second compression chamber. 2 includes a discharge valve (24).

The conventional double rotary compressor as described above operates as follows.

That is, when the rotor 4 is rotated by applying power to the stator 3 of the power transmission mechanism 2, the rotating shaft 5 rotates together with the rotor 4, and the rotational force of the power transmission mechanism 2 is firstly increased. It is transmitted to the compression mechanism section 10 and the second compression mechanism section 20 to the rolling pistons 14, 23 and vanes (not shown) in the internal spaces 19 and 29 of the respective compression mechanism sections 10 and 20. The refrigerant gas is sucked and compressed to be discharged. At this time, the first compression mechanism 10 and the second compression mechanism 20 were alternately suction, compression, and discharge strokes with a phase difference of approximately 180 °.

In such a conventional multistage rotary compressor, the rolling piston is sucked, compressed, and discharged continuously while one point of contact with the inner diameter of the cylinder is performed. If a lot of load is generated and you want to make a large capacity (hereinafter, power mode), each of the compression units is driven. At this time, the capacity of the compressor will be the sum of the refrigerant discharged by each compression unit. If you want to save power while reducing the load (Saving mode), you can shut off the refrigerant that is drawn into some of the compression units, or fix the vane with a piece, etc. By removing the compartment, the rolling piston does not compress the refrigerant but idles.

Another method of realizing the saving mode is to implement a variable capacity of the refrigerant through the variable speed using an inverter motor equipped with a control drive as a power mechanism.

The structure and operation method of such a conventional variable capacity multistage rotary compressor have the following problems.

First, the method of retracting the vane in the saving mode requires a space for mounting a separate part such as a piece, and increases the number of manufacturing processes.

Second, as the piece is repeatedly impacted on the vanes, the surface may be damaged as time passes, and reliability problems such as wear or foreign matters may be caused.

Third, when an inverter motor is used as the drive unit, it is generally expensive, resulting in an increase in manufacturing cost. Therefore, there is a need to realize variable capacity while using a constant speed motor having a relatively low cost.

Fourth, when the existing constant speed motor is used, the on / off operation is repeated frequently for room temperature control, so the power consumption due to the starting current is increased and the wear of the compressor section increases, thereby reducing the reliability of the compressor and also turning on / off. There is a problem that the comfort control is difficult because the deviation from the set temperature is large.

Fifth, in the case of idling or blocking the suction of the refrigerant, there is a problem in reducing the efficiency of the compressor because some of the compression unit is not used at all.

The present invention has been made in view of the above-described problems of the prior art, an object of the present invention can maximize the compression efficiency while using all the plurality of compression units and can vary the capacity during operation as well as the power consumption and It is to provide a multi-stage rotary compressor to reduce section wear.

Hereinafter, the multi-stage rotary compressor according to the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings. The same items as in the prior art have been given the same reference numerals.

2 is a cross-sectional view showing a first embodiment according to the present invention.

As shown in the drawing, the multi-stage rotary compressor according to the present invention is provided with a casing (1) for communicating a plurality of gas suction pipes (30) (31) and the gas discharge pipe (40), and an upper side of the casing (1). A first compression that is installed in a plurality of layers on the lower side of the casing (1) and generates a rotational force, and receives the rotational force generated by the transmission mechanism (2) by the rotating shaft (5) to compress the refrigerant, respectively. The first sliding valve 121 and the first sliding valve 121 varying the compressor capacity by selectively communicating the mechanism unit 10 and the second compression mechanism unit 20 with the two compression mechanism units 10 and 20. The first back pressure switching unit 160 is configured to independently control the opening and closing operation of the first sliding valve 121 by selectively supplying a high pressure refrigerant gas to the rear surface, respectively.

The electric drive unit (2) is fixed to the inside of the casing (1) to apply power from the outside, and the stator (3) is arranged to have a predetermined gap inside the stator (3) and mutually It consists of a rotor 4 which rotates while acting.

The first compression mechanism (10) is formed in an annular shape and is installed inside the casing (1) and has a first cylinder (11) having a first refrigerant port (17) therein, where the refrigerant is sucked, and the first An upper bearing 12 and an intermediate bearing 110 supporting the rotating shaft 5 in the radial and axial directions while covering the upper and lower sides of the cylinder 11 to form a first inner space 19 together with the rotating shaft ( A first rolling piston 14 rotatably coupled to an upper eccentric portion of 5) and compressing the refrigerant while turning in the first internal space 19 of the first cylinder 11, and the first rolling piston 14. A first vane (not shown) which is radially movably coupled to the first cylinder 11 so as to be in pressure contact with an outer circumferential surface thereof so as to partition the first inner space 19 into a first suction chamber and a first compression chamber, respectively; It is coupled to the front end of the first discharge port 16 provided near the center of the bearing 12 so as to be openable and close to the first compression chamber. For controlling the discharge of the refrigerant gas to be discharged it comprises a first discharge valve (15).

The volume of the internal space 19 of the first cylinder 11 may be the same as the volume of the internal space 29 of the second cylinder 21, which will be described later, but the internal space 19 of the first cylinder 11 is described. ) And the volume of the inner space 29 of the second cylinder 21 may be different.

The second compression mechanism 20 is formed in an annular shape and is installed below the first cylinder 11 inside the casing 1, and includes a second cylinder having a second suction port 27 therein into which refrigerant is sucked. 21 and the intermediate bearing 110 and the lower bearing which cover the upper and lower sides of the second cylinder 21 to form the second inner space 29 together to support the rotation shaft 5 in the radial and axial directions. (22), and a second rolling piston (23) rotatably coupled to the lower eccentric portion of the rotary shaft (5) to compress the refrigerant while turning in the second internal space (29) of the second cylinder (21); A second radially movable coupling to the second cylinder 21 so as to press-contact the outer circumferential surface of the second rolling piston 23 so as to partition the second inner space 29 into a second suction chamber and a second compression chamber, respectively; It is possible to open and close the vane (not shown) and the tip of the second discharge port 26 provided near the center of the lower bearing 22. It made of a second discharge valve 24 for controlling the discharge of the refrigerant gas discharged from the second compression chamber combined.

At this time, the first vane and the second vane, the first suction port 17 and the second suction port 27, the first discharge port 16 and the second discharge port 26 are formed at the same position in the vertical direction, respectively. It is.

The intermediate bearing 110 is formed in the shape of a disk having a shaft hole 111 through which the rotating shaft 5 penetrates in the center thereof, but each inner space 19 of the first cylinder 11 and the second cylinder 21 is formed. , 29) penetrate through the first bypass hole 114 in the axial direction. In more detail, when the position of the first bypass hole 114 is described, the first bypass hole 114 is formed to communicate the compression chambers of the first and second internal spaces 19 and 29. desirable. The first valve hole 112 having a predetermined depth is formed to communicate with the first bypass hole 114 in a radial direction so that the first sliding valve 121 is slidably engaged.

The first back pressure switching unit 160 is a kind of pilot valve, and includes a first switching valve housing 165 forming a high pressure side inlet 162, a low pressure side inlet 163, and a common side outlet 164. The first switching valve housing 165 is slidably coupled to selectively connect the high pressure side inlet 162 and the common side outlet 164 or the low pressure side inlet 163 and the common side outlet 164. A first electromagnet 167 installed at one side of the first switching valve 166 and the first switching valve housing 165 to move the first switching valve 166 by an applied power source, and the first The first switching spring 168 restores the first switching valve 166 when the power applied to the electromagnet 167 is cut off.

The first back pressure switching unit 160 is connected to the gas discharge pipe 40 so as to supply a high pressure formed inside the casing 1 to the high pressure side inlet 162, respectively, the first high pressure connection pipe 172. And a first low pressure connecting pipe 173 for supplying low pressure by connecting an intermediate portion of the connection pipe 33 sucked into the accumulator 6 separating the gas liquid of the refrigerant to the low pressure side inlet 163, and the common side. The first common connecting pipe 174 which connects the outlet 164 to the rear side of the first sliding valve 121 to supply a high pressure atmosphere or a low pressure atmosphere is connected.

3 and 4 is a cross-sectional view showing a part of the capacity variable device of the multi-stage rotary compressor according to the present invention.

As shown in the drawing, inside the inner circumferential surface of the first valve hole 112, the locking projection 123 formed in the first sliding valve 121 is caught when the first sliding valve 121 is closed so that the movement is restricted. The valve stopper 131 is formed to step the valve stopper 116 and the locking protrusion 123 is caught when the first sliding valve 121 opens the first bypass hole 114 to restrict movement. Inserts from outside.

The valve stopper 131 is connected to the common connecting pipe 174 of the first back pressure switching unit 160 to communicate with the refrigerant gas of high pressure or low pressure to the rear surface of the first sliding valve 121. 133 is formed, and a spring fixing end 135 having a thread (unsigned) is formed on the inner circumferential surface of the communication hole 133 to screw and fix the valve spring 141 to be described later.

The inner diameter side (hereinafter, abbreviated as front end) of the first sliding valve 121 is formed of a closed cylinder so as to close the first bypass hole 114, and the other end (hereinafter, abbreviated as rear end). The locking projection 123 is formed on the outer circumferential surface thereof so as to be caught by the valve stop 116 to limit the moving distance of the first sliding valve 121. In addition, on the inner circumferential surface of the front end of the first sliding valve 121, a spring fixing end 125 having a screw thread (unsigned) is formed to be screwed to fix the valve spring 141 by screwing.

The valve spring 141 may be replaced with another elastic member.

As shown in FIG. 4, the first sliding valve 121 has an equilibrium of a pressure acting on one side thereof through the communication hole 133 and a pressure acting on the other side thereof through the first bypass hole 114. In order to achieve this, the valve spring 141 is made of a spring that is tensioned to open the first bypass hole 114 by pulling the first sliding valve 121 toward the valve stopper 131. 3, when the pressure acting on one side of the first sliding valve 121 through the communication hole 133 is greater than the pressure acting on the other side through the first bypass hole 114. As the valve spring 141 extends, the first sliding valve 121 closes the first bypass hole 114.

In FIG. 2, reference numeral 7 denotes a condenser, 8 an expansion mechanism, 9 an evaporator, and 150 an O-ring.

The variable capacity device of the rotary compressor of the present invention as described above has the following effects.

That is, when power is applied to the electric mechanism unit 2, the rotating shaft 5 rotates, and the rotational force is transmitted to the first compression mechanism unit 10 and the second compression mechanism unit 20, so that the first rolling piston 14 and the first rotation mechanism are rotated. 2 The rolling piston 23 is pivoting while being in pressure contact with the inner circumferential surfaces of the inner spaces 19 and 29 of the respective cylinders 11 and 21. At this time, the first vane (not shown) and the second vane (not shown) divide each of the internal spaces 19 and 29 into a suction chamber and a compression chamber. The refrigerant is sucked through the suction ports 17 and 27 formed in the suction chamber. The film is compressed by the volume change in the compression chamber and then discharged into the casing 1 through the discharge ports 16 and 26. The discharged refrigerant is discharged to the condenser 7 of the refrigerating cycle apparatus through the gas discharge pipe 40, and then passes through the expansion mechanism 8 and the evaporator 9 in turn, and then through the gas suction pipes 30 and 31, respectively. (11) (21) repeats a series of processes to be sucked into the interior space (19, 29).

Here, the multi-stage rotary compressor operates while varying the capacity according to the operating state of the air conditioner employing the same. Hereinafter, each of the power mode and the saving mode will be described.

First, when the multi-stage rotary compressor operates in the power mode, the first compressor mechanism 10 and the second compressor mechanism 20 respectively operate. That is, as shown in FIG. 3, the power is turned on to the electromagnet 167 of the first back pressure switching unit 160, which is a pilot valve, so that the first switching valve 166 beats the switching spring 168 and the high pressure side inlet. 162 and the common side outlet 164 to communicate. The high pressure side inlet 162 is connected to the first high pressure connecting pipe 172, and the first high pressure connecting pipe 172 is connected to the gas discharge pipe 40, so that the discharge pressure is the first common connection pipe 174. It acts on one side of the first sliding valve 121 through the communication hole 133. On the other side of the first sliding valve 121, the internal pressure of each of the cylinders 11 and 21 acts through the first bypass hole 114, and the pressure is smaller than the discharge pressure, so that the valve spring 141 is tensioned. The first sliding valve 121 is advanced to block the first bypass hole 114. As a result, the refrigerant gas sucked into the first cylinder 11 and the refrigerant gas sucked into the second cylinder 21 are completely compressed without being mixed with each other and discharged into the casing 1, respectively.

Next, the case where the multi-stage rotary compressor operates in the saving mode is as follows. As shown in FIG. 4, the power is turned off to the electromagnet 167 of the first back pressure switching unit 160 to communicate the low pressure side inlet 163 and the common side outlet 164. The low pressure side inlet 163 is connected to the first low pressure connecting pipe 173 and the connecting pipe 33 to flow a low pressure refrigerant, and the refrigerant flows through the communication hole 133 of the first sliding valve 121. It is supplied to the back side. In this state, the first sliding valve 121 is retracted by the compression force of the valve spring 141 to open the first bypass hole 114, and the inner spaces 19 and 29 of the respective cylinders 11 and 21 are opened. Each compression chamber (not shown) is in communication. The first rolling piston 14 and the second rolling piston 23 are disposed so that the phase difference is 180 degrees, and the first bypass hole 114 is formed in the internal space 19 of the first compression mechanism part 10. ) And the second compression chamber in which the first bypass hole 114 is exposed in the internal space 29 of the second compression mechanism 20, the volume of the first compression chamber and the second compression mechanism 20 are different from each other. That is, when the pressure of the first compression chamber is higher than the pressure of the second compression chamber, the refrigerant moves from the first compression chamber to the second compression chamber through the first bypass hole 114, and thus the refrigerant is not compressed.

From the position where rotation continues and the first rolling piston 14 or the upper eccentric closes the first bypass hole 114, the refrigerant is no longer bypassed and the refrigerant is compressed in the first compression chamber so that the first discharge port It is discharged through the (16). That is, since some refrigerant is bypassed and some refrigerant is compressed and discharged, the amount of refrigerant discharged is reduced.

In the same manner, when the pressure of the second compression chamber is higher than the pressure of the first compression chamber, the refrigerant moves from the second compression chamber to the first compression chamber through the first bypass hole 114 and thus the refrigerant is not compressed. From the position where the second rolling piston 23 or the eccentric portion closes the first bypass hole 114, the refrigerant is no longer bypassed and the refrigerant is compressed and discharged.

When each of the compression units 10 and 20 operates in the saving mode, only a portion of the refrigerant is compressed and discharged as it is not compressed as much as the total volume of each compression chamber but is bypassed from a place where the pressure of the compression chamber is high to a low pressure interior space. As this process is repeated, the discharge capacity of the refrigerant is reduced. In this way, the capacity of the power mode and the saving mode can be varied.

Hereinafter, a second embodiment of the present invention will be described. In the second embodiment, a plurality of bypass holes formed in the first embodiment are formed to achieve a multi-stage capacity change.

5 is a partial cutaway view showing a second embodiment of the present invention, Figure 6 is a perspective view showing a broken middle bearing according to a second embodiment of the present invention. The same reference numerals are used for the same items as in the first embodiment.

As shown in the drawing, the intermediate bearing 210 is formed in a disk shape having a shaft hole 311 through which the rotating shaft 5 penetrates in the center thereof, but the second bypass hole 234 and the first bearing are formed at one side of the vane. 3 The bypass hole 235 is formed through the axial direction.

The second bypass hole 234 and the third bypass hole 235 are sequentially formed along the direction of rotation of the rotary shaft based on the vanes. For example, the second bypass hole 234 may be formed near 160 ° in the rotational direction of the rotational axis with respect to the first vane, and the third bypass hole 235 may be formed near 240 °. .

In addition, the second bypass hole 234 and the third bypass hole 235 are radially communicated with each other so that the second sliding valve 231 and the third sliding valve 232 are slidably coupled to each other. The second valve hole 243 and the third valve hole 244 are formed.

The second back pressure switching unit 211 is a pilot valve, and includes a second switching valve housing 215 forming a high pressure side inlet 212, a low pressure side inlet 213, and a common side outlet 214. The second switching valve housing 215 is slidably engaged to selectively connect the high pressure side inlet 212 and the common side outlet 214 or the low pressure side inlet 213 and the common side outlet 214. A second electromagnet 217 installed on one side of the second switching valve 216 and the second switching valve housing 215 to move the second switching valve 216 by an applied power source, and the second electromagnet A second switching spring 218 for restoring the second switching valve 216 when the power applied to 217 is cut off.

The second back pressure switching unit 211 is connected to the gas discharge pipe 40 to supply the high pressure formed inside the casing 1 to the high pressure side inlet 212 and the second high pressure connecting pipe 312, respectively. A second low pressure connecting pipe 313 for supplying low pressure by connecting an intermediate portion of the connection pipe 33 connected to each refrigerant suction pipe 30 and 31 to the low pressure side inlet 213, and the common side outlet 214; ) Is connected to the rear side of the second sliding valve 231 to connect the second common connecting pipe 314 for supplying a high pressure atmosphere or a low pressure atmosphere.

The third back pressure switching unit 221 is a kind of pilot valve, and includes a third switching valve housing 225 forming a high pressure side inlet 222, a low pressure side inlet 223, and a common side outlet 224. Slip the inner side of the third switching valve housing 225 to selectively connect the high pressure side inlet 222 and the common side outlet 224 or the low pressure side inlet 223 and the common side outlet 224. A third electromagnet 227 installed at one side of the third selector valve 226, the third selector valve housing 225 to move the third selector valve 226 by an applied power source, and the third electromagnet A third switching spring 228 for restoring the third switching valve 226 when the power applied to 227 is cut off.

The third back pressure switching unit 221 and the third high pressure connecting pipe 322 to connect with the gas discharge pipe 40 to supply the high pressure formed in the casing 1 to the high pressure side inlet 222, respectively; And a third low pressure connecting pipe 323 for supplying low pressure by connecting the middle of the connecting pipe 33 connected to each refrigerant suction pipe 30 and 31 to the low pressure side inlet 223, and the common side outlet 224. ) Is connected to the rear side of the third sliding valve 232 to connect the third common connection pipe 324 for supplying a high pressure atmosphere or a low pressure atmosphere.

As shown in FIG. 6, inside the inner circumferential surface of the second valve hole 243, when the second sliding valve 231 is closed, the locking protrusion 223 of the second sliding valve 231 is caught to restrict movement. The valve stopper 236 is formed to be stepped, and when the second sliding valve 231 is opened, the valve stopper (not shown) is inserted and coupled from the outside so that the locking protrusion 223 is caught and the movement is restricted. do.

In addition, similarly, a valve stop is applied to the inside of the inner circumferential surface of the third valve hole 244 so that the locking protrusion 233 of the third sliding valve 232 is caught when the third sliding valve 232 is closed. The jaw 237 is formed to be stepped, and when the third sliding valve 232 is opened, the stopper 233 is caught and the valve stopper (not shown) is inserted and coupled from the outside to limit movement.

The structure of the valve stopper is the same as in the first embodiment. In addition, to form a spring fixing end (not shown) with a screw thread on the inner peripheral surface of the front end of the second, third sliding valves (231, 232) to screw the valve springs (241, 242). Same as the first embodiment.

Hereinafter, the operation and effect of the second embodiment of the present invention will be described.

7, 8 and 9 are operation cross-sectional views for explaining the operation according to the second embodiment of the present invention.

First, the power mode will be described. In this case, each of the compression mechanism units 10 and 20 operates to discharge 100% of the refrigerant flow rate. As shown in FIG. 7, the power is turned on to the electromagnet 217 of the second back pressure switching unit 211, which is a pilot valve, so that the second switching valve 216 beats the switching spring 218 and is on the high pressure side. The inlet 212 and the common side outlet 214 are in communication. In this state, the discharge pressure acting on one side of the second sliding valve 231 becomes higher than the internal pressure of each of the cylinders 11 and 21 acting on the other side of the second sliding valve 231. 231 is advanced to block the second bypass hole 234. Similarly, when the electromagnet 227 of the third back pressure switching unit 221 is turned on to communicate the high pressure side inlet 322 and the common side outlet 324, the third sliding valve 232 advances and the third bypass hole ( Block 235). Therefore, the refrigerant gas sucked into the first cylinder 11 and the refrigerant gas sucked into the second cylinder 21 are completely compressed without being mixed with each other and are alternately discharged into the casing 1. As a result, the refrigerant gas sucked into the first cylinder 11 and the refrigerant gas sucked into the second cylinder 21 are completely compressed without being mixed with each other and discharged into the casing 1, respectively.

Next, the case where the multi-stage rotary compressor operates in the saving mode is as follows. As shown in FIG. 8, the power is turned on to the electromagnet 217 of the second back pressure switching unit 211 so that the second switching valve 216 overcomes the switching spring 218 and the high pressure side inlet 212. And the common side outlet 214 are communicated. In this state, the discharge pressure acting on one side of the second sliding valve 231 becomes higher than the internal pressure of each of the cylinders 11 and 21 acting on the other side of the second sliding valve 231. 231 is advanced to block the second bypass hole 234. On the contrary, the power is turned off to the electromagnet 227 of the third back pressure switching unit 221 to communicate the low pressure side inlet 223 and the common side outlet 224. The low pressure side inlet 223 is connected to the third low pressure connecting pipe and the connecting pipe so that a low pressure refrigerant flows, and the refrigerant is supplied to the rear surface of the third sliding valve 232 through the communication hole. In this state, the third sliding valve 232 is retracted by the compression force of the valve spring to open the third bypass hole 235 to communicate each compression chamber in the inner space of each cylinder. That is, as in the saving mode of the first embodiment, the refrigerant is not compressed because it moves from the high compression chamber to the low compression chamber through the third bypass hole 235. The refrigerant moves from the high pressure chamber to the low pressure chamber through the third bypass hole 235, whereby the refrigerant is not compressed and the rolling piston or the eccentric closes the third bypass hole 235. From now on, the refrigerant is no longer bypassed and the refrigerant is compressed and discharged as in the first embodiment. When operating in the saving mode, only some of the refrigerant is compressed and discharged, bypassing the entire volume of each compression chamber and bypassing from the high pressure of the compression chamber to the low pressure internal space. Will be reduced.

Next, if you want to implement a different discharge capacity in the saving mode, as shown in Figure 9, by operating the second, third back pressure switching unit (211, 221) to open the second bypass hole 234 and the third bypass The pass hole 235 is closed. The second bypass hole 234 is located closer to the vane 410 and 420 in the rotational direction of the rotary shaft than the third bypass hole 235. 160 °, the third bypass hole is 240 °) Therefore, the rolling piston or the eccentric portion closes the second bypass hole 234 so that the refrigerant is discharged by being compressed and discharged without the refrigerant being bypassed anymore. The bypass hole 235 is closed, more than the amount of refrigerant discharged. Therefore, the discharge amount of the refrigerant can be varied even in the saving mode.

In the same manner, three or more bypass holes may be formed in the intermediate bearing to realize multi-stage capacity variation.

As described above, the multistage rotary compressor of the present invention has the following effects.

First, the present invention does not require separate parts and mounting space, compared to the method of retracting the vane in the saving mode, the manufacturing process is simple. In addition, since a piece for retreating and fixing the vane is not necessary, wear and foreign matters are not generated, thereby improving reliability.

Secondly, since the plurality of compression units are used in the saving mode, not only the efficiency of the motor and the compressor is improved but also the power saving effect can be obtained.

Third, the capacity is variable while using a low-speed constant speed motor can reduce the manufacturing cost.

Claims (15)

A first suction port and a first discharge port having a first rolling piston and a first rolling piston and a first vane in a linear motion in contact with the first rolling piston in a linear movement is divided into a first suction chamber and a first compression chamber is partitioned Cylinders, A second cylinder having a second suction port and a second discharge port and partitioned into a second suction chamber and a second suction chamber by a second rolling piston that pivots and a second vane that is in direct contact with the second rolling piston; Wow, A plurality of valve holes which are inserted between the first cylinder and the second cylinder and form a plurality of bypass holes so as to communicate each compression chamber of the first cylinder and the second cylinder with each other, and communicate with the middle of the bypass holes. The intermediate bearing forming the A plurality of sliding valves slidingly coupled to the valve hole of the intermediate bearing to selectively open and close the bypass hole; And a plurality of back pressure switching units for selectively supplying discharge pressure to one side of the sliding valve. The internal space of the first cylinder comprising the first suction chamber and the first compression chamber and the internal space of the second cylinder composed of the second suction chamber and the second compression chamber have different volumes. Capacity variable device of a multi-stage rotary compressor. The variable capacity apparatus of claim 1, wherein the first suction port and the second suction port, the first discharge port and the second discharge port, and the first vane and the second vane are disposed in parallel with each other in the vertical direction. delete delete delete delete 2. The variable displacement device of claim 1, wherein the sliding valve is formed of an open cylinder while the other side of the cylinder is closed so that the valve hole can be closed. 9. The method of claim 8, wherein the opening of the sliding end of the sliding valve is formed in the projection, the inner periphery of the valve hole stepped the valve stop so as to limit the movement of the locking projection of the sliding valve during the closing operation of the sliding valve Capacity variable device of the multi-stage rotary compressor, characterized in that for forming a fork. 10. The variable capacity apparatus of claim 9, wherein a valve stopper is provided at an outer side of the valve hole so that the opening end of the sliding valve is caught when the sliding valve is opened. The variable capacity device of claim 10, wherein an elastic member is interposed between the sliding valve and the valve stopper. 12. The multistage rotary compressor of claim 11, wherein the elastic member comprises a tension spring to pull the sliding valve toward the valve stopper to open the bypass hole when the cylinder side pressure and the back pressure of the sliding valve are balanced. Capacity variable device. The method of claim 1, wherein the back pressure switching unit comprises: a first switching valve housing forming a high pressure side inlet, a low pressure side inlet, and a common side outlet; A switching valve which is slidably coupled to the inside of the switching valve housing and selectively connects the high pressure side inlet and the common side outlet or the low pressure side inlet and the common side outlet; An electromagnet installed at one side of the switching valve housing and moving the switching valve by an applied power source; And a switching spring for restoring the switching valve when the electric power applied to the electromagnet is cut off. According to claim 13, wherein the back pressure switching unit is a high-pressure connection pipe connected to the gas discharge pipe to supply high pressure to the high-pressure side inlet, A low pressure connecting pipe connected to a suction pipe to supply low pressure to the low pressure side inlet; Capacitance variable device of the multi-stage rotary compressor, characterized in that the common connecting pipe for supplying a high pressure or a low pressure by connecting the common side outlet and the back of the sliding valve. 15. The capacity variable device of claim 14, wherein the low pressure connecting tube connects the middle of the connecting tube sucked into the accumulator separating the gas liquid from the refrigerant and the low pressure side inlet.

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