CN100400883C - Device for varying the capacity of a multi-stage rotary compressor - Google Patents

Abstract

A device for changing the capacity of a multi-stage compressor, comprising: a first cylinder provided with a first suction port and a first discharge port, the first cylinder moves linearly with a first orbiting rolling piston and a first The first vane contacted by a rolling piston is divided into a first suction chamber and a first compression chamber; a second cylinder with a second suction port and a second discharge port is formed by a second rolling piston orbiting and a straight line The second vane moving and in contact with the second rolling piston is divided into a second suction chamber and a second compression chamber; an intermediate bearing inserted between the first cylinder and the second cylinder has the a bypass hole communicating between the compression chambers, and the intermediate bearing has a valve hole for communicating with the middle of the bypass hole; a slide valve slidably connected to the valve hole of the intermediate bearing, which can selectively open or close the bypass hole; And the pressure switch unit for selectively sending the discharge pressure to one side of the spool valve, so it is possible to change the capacity using all of the multiple compression units, and the energy saving effect suitable for the saving mode can be obtained.

Description

Device for varying the capacity of a multi-stage rotary compressor

technical field

The present invention relates to a rotary compressor performing multi-stage compression, and more particularly to a multi-stage rotary compressor capable of using all compression units to achieve optimum compression efficiency.

Background technique

A compressor is a device that receives energy from an energy generator such as an electric motor to compress air, refrigerant gas, or other specialized gas to increase pressure and is widely used in industry. Depending on how compression is performed, compressors can be classified into positive displacement compressors and turbo compressors. Positive displacement compressors perform compression by a compression method in which pressure is increased by volume reduction; and turbo compressors perform compression by converting kinetic energy of gas into pressure energy.

A rotary compressor, which is a type of positive displacement compressor, is generally used in an air conditioning apparatus such as an air conditioner. In order to meet the need for various functions of the air conditioner, a rotary compressor capable of changing its capacity is currently required.

Rotary compressors use refrigerants containing CFC-based chlorine. However, it is well known that such refrigerants cause the destruction of the ozone layer, thereby contributing to global warming. As a result, the use of this refrigerant is restricted by law, and research on alternative refrigerants to existing refrigerants has been extensively conducted. Carbon dioxide is expected as an alternative refrigerant. Furthermore, global warming raises issues of improvement in energy efficiency of devices as well as issues of substitution of existing refrigerants.

Of course, the compressor is considered to be the heart of the refrigeration system, and the biggest concern is how an alternative refrigerant that is not harmful to the global environment can be used in the existing compressor without loss of performance.

There is a multi-stage rotary compressor having a plurality of compression units capable of changing their capacity and using alternative refrigerants.

FIG. 1 shows a cross-sectional view of one example of a conventional multi-stage rotary compressor.

As shown in the figure, a conventional multi-stage rotary compressor includes: a housing 1 equipped with two suction pipes 30 and 31 communicating with each other and a discharge pipe 40; installed on the upper side of the housing 1 and containing a stator 3 and the motor unit 2 of the rotor 4 for generating rotational force; and the first compression unit 10 and the second compression unit 20 installed on the upper and lower parts of the lower side of the housing 1, which pass through the motor unit 2 according to the rotational force generated by the motor unit 2, respectively The shaft 5 is rotated to compress the refrigerant.

An accumulator 6 for separating liquefied refrigerant from sucked refrigerant is installed between the suction pipes 30 and 31 and between the compression units 10 and 20 . The first suction pipe 30 sends the refrigerant into the first cylinder 11 by being connected with the first suction port 17 , and the second suction pipe 31 sends the refrigerant into the second cylinder 21 by being connected with the second suction port 27 .

The first compression unit 10 includes: a ring-shaped first cylinder 11 installed inside the housing 1; the upper bearing 12 and the middle bearing 13 cover the upper and lower sides of the first cylinder 11, forming a first internal space 19 together, and The rotary shaft 5 is supported in the radial and axial directions; the first rolling piston 14 is rotatably connected with the upper eccentric portion of the rotary shaft 5, and it orbits in the first inner space 19 of the first cylinder 11 to compress Refrigerant; the first vane (not shown) connected to the first cylinder is movable in the radial direction so as to be in contact with the outer peripheral surface of the first rolling piston 14, and the first vane connects the first cylinder 11 The first internal space 19 is divided into a first suction chamber and a first compression chamber; and a first discharge valve 15 which is connected to the front end of the first discharge port 16 arranged on the upper bearing 12 to open or close the first discharge port 16, for Control the discharge of refrigerant gas.

The second compression unit 20 includes: a ring-shaped second cylinder 21 installed inside the housing 1 and at the bottom of the first cylinder 11; the middle bearing 13 and the lower bearing 22 cover the upper and lower sides of the second cylinder 21 to form a second cylinder together. inner space, and supports the rotating shaft 5 in radial and axial directions; a second rolling piston 23 rotatably connected with the lower eccentric part of the rotating shaft, and it rotates in the second inner space of the second cylinder 21 The second vane (not shown) connected to the second cylinder 21 is movable in the radial direction so as to be in contact with the outer peripheral surface of the second rolling piston 23, and the second vane moves the second The inner space 29 is divided into a second suction chamber and a second compression chamber; and a second discharge valve 24 which is connected to the front end of the second discharge port 26 arranged on the lower bearing 22 to open or close the second discharge port 26 for controlling refrigeration The discharge of agent gas from the second compression chamber.

The operation of the conventional multi-stage rotary compressor having such a structure will be described below.

When energy is supplied to the stator 3 of the motor unit 2 and the rotor 4 rotates, the rotation shaft 5 rotates together with the rotor 4 , thereby transmitting the rotational force of the motor unit 2 to the first compression unit 10 and the second compression unit 20 . Accordingly, by rolling the pistons 14 and 23 and vanes (not shown), refrigerant gas is sucked into the inner spaces 19 and 29 of the compression units 10 and 20 and compressed therein. At this time, in the first compression unit 10 and the second compression unit 20, suction, compression, and discharge strokes are alternately performed with a phase difference of about 180 degrees.

Such a conventional multi-stage rotary compressor continuously performs suction, compression, and discharge of refrigerant since the rolling piston contacts the inner diameter of the cylinder at one point. In order to generate larger loads and thus obtain large capacities (hereinafter referred to as power modes), the compression units are driven separately. At this time, the capacity of the compressor is the sum of the refrigerant discharged by each compression unit. In order to obtain the energy-saving effect of low capacity due to reduced load (hereinafter referred to as saving mode), some of the refrigerant sucked by the compression unit is cut off, or the vane is moved backward and fixed by a piece, etc., thereby moving Except at the boundary between the suction chamber and the compression chamber, the rolling piston does not compress the refrigerant but runs idle.

As another method of realizing the saving mode, the amount of refrigerant is varied by varying the speed by using an inverter motor with control drive as a drive unit.

The structure of the general rotary compressor and the driving method therefor have the following problems.

First, in the economizing mode, the method in which the blades are moved backward and fixed has a problem that special components such as parts and the installation space of the components are not ideal and increase the number of manufacturing processes.

Second, since parts repeatedly collide with the blade, the surface of the blade may be damaged over time, and reliability problems such as wear, generation of foreign matter, and the like may be caused.

Third, since variable frequency motors are generally expensive, using a variable frequency motor as a drive unit may cause an increase in manufacturing costs. Therefore, relatively inexpensive constant speed motors are required to achieve capacity changes.

Fourth, when using an existing constant-speed motor, frequently repeat ON/OFF operations to control room temperature. For this reason, since the energy consumption of the starting current is large, this accelerates the occurrence of wear of the compression unit and causes a reduction in the reliability of the compression unit. Moreover, since the variation between the set temperature and the room temperature is also large in ON/OFF of the constant speed motor, it is difficult to control the room temperature to a satisfactory state.

Fifth, when the compression units are idling or refrigerant intake is blocked, some compression units are not used at all, which also reduces the efficiency of the compressor.

Contents of the invention

Accordingly, an object of the present invention is to provide a multi-stage rotary compressor capable of maximizing compression efficiency using all compression units, varying capacity in operation, and reducing consumed energy and wear between components.

In order to achieve these and other advantages of the present invention and according to the purpose of the present invention, it is specifically and generally described here that a device for changing the capacity of a multi-stage compressor is provided, including: a first suction port and The first cylinder of the first discharge port is divided into the first suction chamber and the first compression chamber by the orbiting first rolling piston and the first vane that moves linearly and contacts the first rolling piston; A second cylinder with two suction ports and a second discharge port, the second cylinder is divided into a second suction chamber and a second compression chamber by a second rolling piston that orbits and a second blade that moves linearly and contacts the second rolling piston ; an intermediate bearing inserted between the first cylinder and the second cylinder, the intermediate bearing has a bypass hole communicating between the compression chambers of the first cylinder and the second cylinder, and the intermediate bearing has a middle part for communicating with the bypass hole a valve hole; a spool valve slidably connected to the valve hole of the intermediate bearing, which can selectively open or close the bypass hole; and a pressure switch unit for selectively sending discharge pressure to one side of the spool valve. The spool is formed to have a cylindrical shape, a stopper protrusion is formed at one end of the spool, and the valve stopper is formed to have a stepped surface on the inner peripheral surface of the valve hole so as to pass through the stopper during the closing operation of the spool. The blocking protrusions limit the movement of the spool valve.

The aforementioned and other objects, features, aspects and advantages of the present invention will become more apparent through the following detailed description of the present invention in conjunction with the accompanying drawings.

Description of drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The specific embodiments shown in the present invention are used together with the description to clarify the principle of the present invention.

In the attached picture:

FIG. 1 shows a cross-sectional view of an example of a conventional multistage rotary compressor;

Fig. 2 shows a cross-sectional view of a multi-stage rotary compressor according to a first embodiment of the present invention;

Fig. 3 shows a cross-sectional view of a bypass hole in a closed state according to the first embodiment of the present invention;

Fig. 4 shows a cross-sectional view of the opening state of the bypass hole according to the first embodiment of the present invention;

Figure 5 shows a partially cutaway view of a multi-stage rotary compressor according to a second embodiment of the present invention;

Figure 6 shows a partially exploded perspective view of the main components according to a second embodiment of the present invention; and

Figures 7, 8 and 9 show cross-sectional views operating in accordance with a second embodiment of the invention.

Detailed ways

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The same reference numerals refer to the same components as in the conventional art.

Fig. 2 shows a sectional view of a multi-stage rotary compressor according to a first embodiment of the present invention.

As shown in the figure, the multi-stage rotary compressor according to the present invention includes: a casing 1 equipped with a plurality of suction pipes 30 and 31 communicating with each other and a discharge pipe 40; A motor unit 2 generating a rotational force; a first compression unit 10 and a second compression unit 20 mounted on the lower side of the housing 1 in a multi-stage manner, for receiving the rotational force generated by the motor unit 2 through the rotating shaft 5 respectively compressing refrigerant; a first slide valve 121 selectively communicating with the two compression units 10 and 20 for selectively changing the capacity of the compressor; and selectively sending high-pressure refrigerant gas into the first slide valve 121 The first pressure switch unit 160 at the rear is used to independently control the opening/closing operation of the first spool valve 121 .

The motor unit 2 includes: a stator 3 fixed in the casing 1 and receiving energy from the outside;

The first compression unit 10 includes: a first cylinder 11 that is installed inside the housing 1 and forms an annular shape, and has a first-suction port 17 that sucks refrigerant therein; an upper bearing 12 and a middle bearing 110 that cover the upper and lower sides of the first cylinder 11 Both sides form the first internal space 19 together, and support the rotating shaft 5 in the radial and axial directions; the first rolling piston (rolling piston) 14 that is rotatably connected to the upper eccentric portion of the rotating shaft 5, which is in the Rotate in the first internal space 19 of the first cylinder 11, thereby compressing the refrigerant; the first vane (not shown) that is movably connected with the first cylinder 1 in the radial direction, which can be connected with the first rolling piston 14 The outer circumferential surface of the upper bearing 12 is in pressure contact, and the first vane divides the first internal space 19 into a first suction chamber and a first compression chamber; Close the first discharge valve 15 of the first discharge port 16, which valve controls the discharge of refrigerant gas from the first compression chamber.

The inner space 19 of the first cylinder 11 may have the same volume as the inner space 29 of the second cylinder 21 described later. However, the volume of the inner space 19 can also differ from the volume of the inner space 29 .

The second compression unit 20 includes: the second cylinder 21 which is installed in the lower part of the first cylinder 11 in the housing 1 and forms an annular shape, and has a second suction port 27 for sucking refrigerant therein; the middle bearing 110 and the lower bearing 22 cover the second Both the upper and lower sides of the cylinder 21 form the second internal space 29 together, and support the rotating shaft 5 in the radial and axial directions; The piston 23 revolves in the second internal space 29 of the second cylinder 21, thereby compressing the refrigerant; the second vane (not shown) is movably connected with the second cylinder 21 in the radial direction, so that it can be connected with the The outer peripheral surface of the second rolling piston 23 is in pressure contact, and the second vane divides the second internal space 29 into a second suction chamber and a second compression chamber; The second discharge valve 24 connected to open or close the second discharge port 26 controls the discharge of refrigerant gas from the second compression chamber.

At this time, the first blade and the second blade are arranged side by side in the horizontal direction, the first suction port 17 and the second suction port 27 are also arranged side by side in the horizontal direction, and the first discharge port 16 and the second suction port are arranged vertically. The two outlets 26 are arranged collinearly.

The intermediate bearing 110 is in the shape of a disc having a shaft hole 111 at its center through which the rotating shaft 5 passes. A bypass hole 114 is formed through the intermediate bearing 110 in the axial direction so that the inner spaces 19 and 29 of the first cylinder 11 and the second cylinder 21 communicate with each other. In more detail, the first bypass hole 114 is preferably formed so that the compression chambers of the first and second internal spaces 19 and 29 can communicate with each other. In the radial direction, a first valve hole 112 communicating with the first bypass hole 114 is formed at the intermediate bearing 110 so that the first spool valve 121 can be slidably connected thereto.

The pressure switch unit 160 is a pilot valve (pilot valve), which includes: a first switch valve housing 165, which is provided with a high-pressure inlet 162, a low-pressure inlet 163 and a common outlet 164; a first switch valve 166, which is slidably connected to the first switch Inside the valve housing 165 and selectively connect the high-pressure inlet 162 with the common outlet 164 or the low-pressure inlet 163 with the common outlet 164; the first electromagnet 167 is installed on one side of the first switch valve housing 165 and moves the second valve by the applied energy. an on-off valve 166; and a first on-off spring 168 for restoring the first on-off valve 166 when the energy supplied to the first electromagnet 167 is cut off.

For the first pressure switch unit 160, the high-pressure inlet 162 is connected to the exhaust pipe 40 through the first high-pressure connecting pipe 172, so that the high pressure formed in the housing 1 is sent into the high-pressure inlet 162, and through the first low-pressure connecting pipe 173, the low pressure The inlet 163 is connected to the middle of the connection pipe 33 so that low pressure is sent into the low pressure inlet 163 through which the refrigerant is sucked into the accumulator 6 for separating gas-liquid from the refrigerant. And the first common connection pipe 174 connects the common outlet 164 to the rear side of the first slide valve 121, thereby sending high-pressure air or low-pressure air into the rear side.

Figures 3 and 4 are cross-sectional views showing partly the means for varying the capacity of the multi-stage rotary compressor of the present invention.

As shown in the figure, in order to restrict the movement of the first spool valve 121 by blocking the stop protrusion 123 formed on the first spool valve 121 when the first spool valve 121 is closed, a valve stop protrusion 116 is steppedly formed on the first valve spool 121. The inner side of the inner peripheral surface of the hole 112 . When the first spool valve 121 opens the first bypass hole 114 , in order to limit the movement of the first spool valve 121 by blocking the blocking protrusion 123 , the valve stopper 131 is inserted into the valve hole 112 from the outside.

The valve stopper 131 has a communication hole 133 connected to the common connection pipe 174 of the first pressure switch unit 160 so that high-pressure or low-pressure refrigerant gas can be sent into the rear of the first slide valve 121 . A spring fixing step 135 having threads (not shown) is formed on the inner circumferential surface of the communication hole 133 so as to be screwed with a valve spring 141 described later.

The first slide valve has a cylindrical shape whose inner diameter side (hereinafter referred to as front end) is closed. On the outer circumferential surface of the other end portion of the first spool valve 121 (hereinafter referred to as the rear end), a stopper protrusion 123 is protrudingly formed, which limits the moving distance of the first spool valve 121 by being caught by the valve stopper protrusion 116 . Also, a spring fixing step 125 having threads (not shown) for fixing the valve spring 141 by screwing is formed stepwise on the inner peripheral surface of the front end of the first spool valve 121 .

The valve spring 141 can be replaced by other elastic components.

As shown in FIG. 4, a valve spring 141 is installed inside the first spool valve. Here, the valve spring is an extended spring that is compressed when the pressure applied to one side thereof through the communication hole 133 and the pressure applied to the other side thereof through the first bypass hole 114 are balanced. , so that the first spool valve 121 is pulled toward the valve stopper 131 to open the first bypass hole 114 . On the contrary, as shown in FIG. 3, when the pressure applied to one side of the first spool valve 121 through the communication hole 133 is greater than the pressure applied to the other side thereof through the first bypass hole 114, the valve spring 141 stretches, Thus, the first spool valve 121 closes the first bypass hole 114 .

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

The device for varying the capacity of the rotary compressor according to the invention operates as follows.

That is, when power is supplied to the motor unit 2 , the rotation shaft 5 is rotated, and the rotational force is transmitted to the first compression unit 10 and the second compression unit 20 . Accordingly, the first rolling piston 14 and the second rolling piston 23 orbit and are brought into pressure contact with the inner circumferential surfaces of the inner spaces 19 and 29 of the cylinders 11 and 21, respectively. At this time, each of the first and second vanes (not shown) divides the inner spaces 19 and 29 into a suction chamber and a compression chamber. The refrigerant is sucked through suction ports 17 and 27 formed in the suction chamber, compressed by volume change in the compression chamber, and discharged into the casing 1 through discharge ports 16 and 26 . The discharged refrigerant is sprayed to the condenser 7 of the refrigeration cycle through the exhaust pipe 40, and passes through the expansion device 8 and the evaporator 9 in sequence, and then is sucked into the inner spaces 19 and 19 of each cylinder 11 and 21 through the suction pipes 30 and 31 again. 29. Repeat this process.

Here, the multi-stage rotary compressor operates changing its capacity according to the operating state of the air conditioner using it. The energy mode and the saving mode are respectively described below.

First, the multi-stage rotary compressor operates in an energy mode when the first compression unit 10 and the second compression unit 20 operate separately. That is, as shown in FIG. 3 , the electromagnet 167 (pilot valve) of the first pressure switch unit 160 is turned on so that the first switch valve 166 overcomes the switch spring 168 and communicates between the high pressure inlet 162 and the common outlet 164 . Here, the high-pressure inlet 162 is connected to the first high-pressure connection pipe 172 , and the first high-pressure connection pipe 172 is connected to the exhaust pipe 40 . For this, a discharge pressure is applied to one side of the first spool valve 121 through the first common connection pipe 174 and the communication hole 133 . At this time, the internal pressure of each of the cylinders 11 and 21 is applied to the other side of the first spool valve 121 through the first bypass hole 114 and is smaller than the discharge pressure. Accordingly, the valve spring 140 expands, moving the first spool valve 121 forward to block the first bypass hole 114 . Therefore, the refrigerant gas sucked into the first cylinder 11 and the refrigerant gas sucked into the second cylinder 21 are not mixed together but are compressed and discharged to the casing 1 separately.

Then, the operation of the multi-stage rotary compressor in the economizing mode will be described below. As shown in FIG. 4 , the electromagnet 167 of the first pressure switch unit 160 is closed to enable communication between the low pressure inlet 163 and the common outlet 164 . The low-pressure inlet 163 is connected to the first low-pressure connection pipe 173 and the connection pipe 33 so that low-pressure refrigerant flows therein. Such refrigerant is sent into the rear surface of the first slide valve 121 through the communication hole 13 . When such a state is reached, the first spool valve 121 is moved backward by the compression force of the valve spring 141 , thereby opening the first bypass hole 114 . Through the opening of the first bypass hole 114, the compression chambers (not shown) of the inner spaces 19 of the cylinders 11 and 21 communicate with each other. The first rolling piston 14 and the second rolling piston 23 are arranged with a phase difference of 180 degrees, and the volume and internal pressure of the first compression chamber in the inner space 19 of the first compression unit 10 where the first bypass hole 114 is exposed are the same as those of the second The volume and the internal pressure of the second compression chamber, to which the first bypass 114 is exposed, of the internal space 29 of the compression unit 20 differ. That is, if the pressure of the first compression chamber is greater 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 cannot be compressed.

From the position where the first bypass hole 114 is closed due to continuous rotation by the first rolling piston 14 or the upper eccentric portion, the refrigerant no longer bypasses but is compressed in the first compression chamber and discharged through the first discharge port 16 . That is, since a part of the refrigerant is bypassed and a part is compressed and discharged, the amount of discharged refrigerant is reduced.

In the same way, if 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 cannot be compressed. Then, from the position where the second rolling piston 23 or the eccentric part closes the first bypass hole 114, the refrigerant does not bypass but is compressed and then discharged.

When each of the compression units 10 and 20 operates in the economizing mode, the refrigerant is not compressed by the entire volume of each compression chamber, and a part of the refrigerant is bypassed from the high pressure compression chamber to the low pressure compression chamber. Only a part of the refrigerant is compressed and discharged. Such a process is repeated, thus reducing the discharge amount of refrigerant. In this way, a change in capacity in energy mode or saving mode can be achieved.

Hereinafter, a second embodiment of the present invention will be described. In the second embodiment, a plurality of bypass holes are formed, so that multi-stage capacity variation can be realized.

5 shows a partially cutaway view of a multi-stage rotary compressor according to a second embodiment of the present invention; and FIG. 6 shows an exploded perspective view of an intermediate bearing according to a second embodiment of the present invention. The same reference numerals designate the same or corresponding components as in the first embodiment.

As shown in the figure, the intermediate bearing 210 is in the shape of a disc, and has a shaft hole 311 at its center through which the rotating shaft 5 passes, and the second bypass hole 234 and the third bypass hole 235 are formed in the axial direction through the side of the blade.

The second bypass hole 234 and the third bypass hole 235 are sequentially formed based on the rotation direction of the blade along the rotation shaft. For example, the second bypass hole 234 is formed around 160 degrees from the first blade along the rotation direction of the rotation shaft, and the third bypass hole may be formed around 240 degrees.

Also, the second valve hole 243 and the third valve hole 244 having a predetermined depth communicate with the second bypass hole 234 and the third bypass hole 235 in the radial direction, and the second spool valve 231 and the third spool valve 232 are respectively Sliding connection with two valve holes.

The second pressure switch unit 211 is a pilot valve, which includes: a second switching valve housing 215 formed with a high pressure inlet 212, a low pressure inlet 213 and a common outlet 214; a second switch slidingly connected inside the second switching valve housing 215 The valve 216 is used to selectively connect the high-pressure inlet 212 with the common outlet 214 or the low-pressure inlet 213 with the common outlet 214; the second electromagnet 217 installed on one side of the second switching valve housing 215 is used to pass the applied energy to move the second on-off valve 216;

In the second pressure switch unit 211, the high-pressure inlet 212 is connected to the exhaust pipe 40 through the second high-pressure connecting pipe 312, so that the high pressure formed in the housing 1 can be sent into the high-pressure inlet 212, and then passed through the second low-pressure connecting pipe 313 , the low-pressure inlet 213 is connected to the middle of the connection pipe 33 connected to each of the refrigerant suction pipes 30 and 31, so that low pressure is sent into the low-pressure inlet 213. Also, the common outlet 213 is connected to the rear of the second slide valve 231 through the second common connection pipe 314, so that high-pressure or low-pressure air can be sent to the rear side.

The third rear pressure switch unit 221 is a pilot valve, which includes: a third switch valve housing 225 formed with a high pressure inlet 222, a low pressure inlet 223 and a common outlet 224; The three switch valves 226 are used to selectively connect the high pressure inlet 222 or the low pressure inlet 223 with the common outlet 224; the third electromagnet 227 installed on one side of the third switch valve casing 225 is used to move the first switch valve by applying energy. The three switch valve 226; and the third switch spring 228 for restoring the third switch valve 226 when the energy sent to the third electromagnet 227 is cut off.

In the third pressure switch unit 221, the high-pressure inlet 222 is connected with the exhaust pipe 40 through the third high-pressure connecting pipe 322, so that the high pressure formed in the casing 1 is sent into the high-pressure inlet 222, and the high-pressure inlet 222 is sent through the third low-pressure connecting pipe 323. , the low-pressure inlet 223 is connected to the middle of the connecting pipe 33 connected to each of the refrigerant suction pipes 30 and 31, so that low pressure is sent into the low-pressure inlet 223. Also, the common outlet 224 is connected to the rear side of the third slide valve 232 through the third common connection pipe 324, so that high pressure or low pressure air pressure can be sent to the rear side.

As shown in FIG. 6, in order to restrict the movement of the second spool valve 231 by blocking the stop protrusion 223 of the second spool valve 231 when the second spool valve 231 is closed, a valve stop protrusion 236 is steppedly formed in the second valve hole. 243 inside of the inner peripheral surface. Also, in order to limit the movement of the second spool valve 231 by blocking the blocking protrusion 223 when the second spool valve 231 is opened, a valve stopper (not shown) is inserted and connected into the valve hole 243 from the outside.

And, in the same way, when the third spool valve 232 is closed, in order to limit the movement of the third spool valve 232 by blocking the stop protrusion 233 of the third spool valve 232, a valve stop projection 237 is stepped and formed in the third valve hole. 244 inside of the inner peripheral surface. Also, in order to limit the movement of the third spool valve 232 by blocking the stopper protrusion 233 when the third spool valve 232 is opened, a valve stopper (not shown) is inserted into the valve hole 244 from the outside.

The structure of the valve stopper is the same as that in the first embodiment. Also, as a first embodiment, there is provided a spring fixing step (not shown) for fixing the threads of the valve springs 241 and 242 by screwing on the inner peripheral surface of each front end of the second and third slide valves 231 and 232. form.

The operation and effect of the second embodiment of the present invention will be described below.

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

First, the energy mode is described below. In the power mode, the compression units 10 and 20 operate separately, discharging 100% of the flux of refrigerant. As shown in FIG. 7 , when the electromagnet 217 (pilot valve) of the second pressure switch unit 211 is turned on, the second switch valve 216 overcomes the switch spring 218 and communicates between the high pressure inlet 212 and the common outlet 214 . When such a state is reached, in each of the cylinders 11 and 21, the discharge pressure applied to one side of the second spool valve 231 is higher than the internal pressure applied to the other side of the second spool valve 231, thereby moving the second spool valve 231 forward. The spool valve 231 blocks the second bypass hole 234 . Also, when the electromagnet 227 of the third pressure switch unit 221 is turned on and communicates between the high pressure inlet 222 and the common outlet 224 , the third spool valve 232 moves forward to block the third bypass hole 235 . Therefore, the refrigerant gas sucked into the first cylinder 11 and the refrigerant gas sucked into the second cylinder 21 are not mixed, but are alternately completely compressed and discharged to the casing 1 .

Then, the operation of the multi-stage rotary compressor in the economizing mode will be described below. As shown in FIG. 8 , when the electromagnet 217 of the second pressure switch unit 211 is turned on, the second switch valve 216 overcomes the switch spring 218 and communicates between the high pressure inlet 212 and the common outlet 214 . When such a state is reached, the discharge pressure applied to one side of the second spool valve 231 is higher than the internal pressure of each of the cylinders 11 and 21 that is applied to the other side of the second spool valve 231. side pressure, thereby moving the second spool valve 231 forward and blocking the second bypass hole 234 . On the contrary, by closing the electromagnet 227 of the third pressure switch unit 221 , the low pressure inlet 223 communicates with the common outlet 224 . Since the low-pressure inlet 233 is connected to the third low-pressure connection pipe and the connection pipe, low-pressure refrigerant flows therein. Such refrigerant is sent into the rear of the third slide valve 232 through the communication hole. When such a state is reached, the third spool valve 232 is moved backward by the compression force of the valve spring, thereby opening the third bypass hole 235 and communicating between the compression chambers of the cylinder inner space. That is, when in the saving mode of the first embodiment, the refrigerant moves from the high-pressure compression chamber to the low-pressure compression chamber through the third bypass hole 235, so the refrigerant cannot be compressed. Then, from the position where the rolling piston or the eccentric part closes the third bypass hole 235, the refrigerant does not bypass but is compressed and discharged. In economizing mode, the refrigerant cannot be compressed with the entire volume of each compression chamber, and is bypassed from the high pressure compression chamber to the low pressure compression chamber. Therefore, only a part of the refrigerant is compressed and discharged. Such a process is repeated, thus reducing the discharge amount of refrigerant.

Then, to realize another discharge amount in the saving mode, as shown in FIG. 9 , the second bypass hole 234 is opened and the third bypass hole 235 is closed by operating the second and third pressure switch units 211 and 221 . Along the rotation direction of the rotating shaft 14 , the second bypass hole 234 is closer to the vanes 410 , 420 than the third bypass hole 235 (for example, 160 degrees for the second bypass hole and 240 degrees for the third bypass hole). Therefore, the amount of refrigerant compressed and discharged when the rolling piston or the eccentric portion closes the second bypass hole 234 is greater than the amount of refrigerant discharged when the third bypass hole 235 is closed. Therefore, the discharged refrigerant amount can be changed even in the economizing mode.

Of course, in the same manner, multi-stage capacity variation can be realized by forming three or more bypass holes in the intermediate bearing.

As described so far, the multi-stage rotary compressor according to the present invention has the following effects.

First, unlike the method in which the blades are moved backward and fixed, the present invention is advantageous in that no special parts and installation space are required, and the manufacturing process is simplified. Also, since parts that move backward and fix the blade are not required, problems such as wear, generation of foreign matter, etc. do not occur, thereby improving reliability.

Second, since a plurality of compression units are all used even in the saving mode, the efficiency of the motor and the compressor is improved and an energy saving effect can be achieved.

Third, manufacturing costs can be reduced due to the use of an inexpensive constant-speed motor to vary capacity.

Since the present invention can be implemented in various ways without departing from the spirit or essential characteristics of the present invention, it can also be understood that the above-mentioned specific embodiments are not limited by any details of the foregoing description, unless otherwise specified, can be Broadly interpreted within the spirit and scope defined in the appended claims, all changes and modifications that come within the metes and bounds of the claims, or equivalents to such metes and bounds are therefore embraced by the appended claims middle.

Claims (14)

1. A device for changing the capacity of a multi-stage compressor, comprising: A first air cylinder with a first suction port and a first discharge port is divided into a first suction chamber and a second air cylinder by a first rolling piston that orbits and a first vane that moves linearly and contacts the first rolling piston. a compression chamber; A second cylinder with a second suction port and a second discharge port is divided into a second suction chamber and a second cylinder by a second rolling piston that orbits and a second vane that moves linearly and contacts the second rolling piston. Two compression chambers; An intermediate bearing inserted between the first cylinder and the second cylinder, the intermediate bearing has a bypass hole for communicating between the compression chambers of the first cylinder and the second cylinder, and the intermediate bearing has a hole for communicating with the middle of the bypass hole valve hole; a spool valve slidably connected to the valve bore of the intermediate bearing, which selectively opens or closes the bypass bore; and A pressure switch unit for selectively sending discharge pressure to one side of the spool valve; Wherein the spool valve is formed to have a cylindrical shape, a stopper protrusion is formed at one end of the spool valve, and the valve stopper protrusion is formed to have a stepped surface on the inner peripheral surface of the valve hole so as to pass through the stopper of the spool valve during the closing operation of the spool valve. The stop protrusion of the valve restricts the movement of the spool valve. 2. The apparatus of claim 1, wherein the volume of the first cylinder interior space having the first suction chamber and the first compression chamber is different from the volume of the second cylinder interior space having the second suction chamber and the second compression chamber . 3. The device according to claim 1, wherein the first suction port and the second suction port are arranged side by side in the horizontal direction, the first discharge port and the second discharge port are arranged collinearly in the vertical direction, and in the horizontal direction In the direction, the first vane and the second vane are arranged side by side. 4. The device according to claim 1, wherein the bypass hole formed in the intermediate bearing is plural. 5. The apparatus as claimed in claim 1, wherein the pressure switch unit is formed in plural. 6. The device of claim 1, wherein the pressure switch unit is a pilot valve. 7. The apparatus of claim 1, wherein a phase difference between the first rolling piston and the second rolling piston is 180 degrees. 8. The apparatus of claim 1, wherein the spool valve is formed to have one closed end and the other open end so as to close the valve hole, and the blocking protrusion is formed at the open end of the spool valve. 9. The apparatus of claim 1, wherein a valve stopper is disposed outside the valve hole so as to limit movement of the spool valve by blocking an open end of the spool valve during an opening operation of the spool valve. 10. The device of claim 9, wherein an elastic member is interposed between the spool valve and the valve stopper. 11. The apparatus of claim 10, wherein the elastic member is a telescoping spring, the elastic member pulls the spool toward the valve stop to open the bypass hole when the pressure on the cylinder side of the spool equalizes the rear pressure. 12. The apparatus of claim 1, wherein the pressure switch unit comprises: A first switching valve housing formed with a high-pressure inlet, a low-pressure inlet and a common outlet; an on-off valve slidingly connected inside the on-off valve housing, which selectively connects the high-pressure inlet or the low-pressure inlet to the common outlet; An electromagnet mounted on the side of the on-off valve housing to move the on-off valve by applied energy; and When the energy sent to the electromagnet is cut off, it is used to return the switching spring of the switching valve. 13. The device as claimed in claim 12, wherein the pressure switch unit is connected with a high-pressure connection pipe connected with the exhaust pipe so as to send high pressure into the high-pressure inlet, a low-pressure connection pipe is connected to the suction pipe, thereby feeding low pressure into the low-pressure inlet, and A common connecting pipe connects the common outlet to the rear of the spool valve, which feeds high or low pressure. 14. The apparatus as claimed in claim 13, wherein a low-pressure connecting pipe connects the low-pressure inlet to a middle portion of the connecting pipe through which the refrigerant is sucked into the accumulator for separating gas-liquid refrigerant.

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