Abstract:
A variable capacity rotary compressor is provided, in which a vane may be restricted by a pressure difference generated between both side surfaces of the vane when the compressor performs in a saving driving mode. The vane may be restricted quickly and stably by rapidly decreasing a pressure of a vane chamber by leaking a discharge pressure of the vane chamber to an inlet via a low pressure passage and thereby increasing a pressurizing force applied to a side surface of the vane relatively greater than a supporting force applied to a rear surface thereof. In this way, the vane may be prevented from being vibrated due to a weak restriction force of the vane when a power driving mode of the compressor is switched into the saving driving mode, which prevents noise from increasing due to design conditions, thereby enhancing a comfort feeling of a user.

Description:
[0001]    The present application claims priority to Korean Application No. 10-2006-0114770 filed in Korea on Nov. 20, 2006 and to U.S. Provisional Patent Application Ser. No. 60/908,034 filed in the United States on Mar. 26, 2007, both of which are herein incorporated by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    A variable capacity rotary compressor is disclosed herein. 
         [0004]    2. Background 
         [0005]    Variable capacity rotary compressors are known. However, they have various disadvantages, in particularly when changing operational modes. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0006]    Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein: 
           [0007]      FIG. 1  is a horizontal sectional view of a variable capacity rotary compressor according to an embodiment; 
           [0008]      FIG. 2  is a horizontal sectional view of another variable capacity rotary compressor according to an embodiment; 
           [0009]      FIG. 3  is a horizontal sectional view of another variable capacity rotary compressor according to the an embodiment; 
           [0010]      FIG. 4  is a graph showing noise characteristics at a time of switching a mode of the variable capacity rotary compressor of  FIG. 3 ; 
           [0011]      FIG. 5  is a longitudinal sectional view of a variable capacity rotary compressor according to an embodiment; 
           [0012]      FIG. 6  is a horizontal sectional view showing a released state of a vane when the variable capacity rotary compressor of  FIG. 5  is in a power driving mode according to an embodiment; 
           [0013]      FIG. 7  is a horizontal sectional view showing a restricted state of a vane when the variable capacity rotary compressor of  FIG. 5  is in a saving driving mode; 
           [0014]      FIG. 8  is an enlarged view showing in detail a process of restricting the vane of  FIG. 7 ; 
           [0015]      FIG. 9  is a graph showing noise characteristics at a time of switching a mode of the variable capacity rotary compressor of  FIG. 5 ; 
           [0016]      FIGS. 10 and 11  are horizontal sectional views each showing a variable capacity rotary compressor according to another embodiment; and 
           [0017]      FIGS. 12-14  are exemplary installations of a variable capacity rotary according to embodiments. 
       
    
    
     DETAILED DESCRIPTION  
       [0018]    Embodiments will now be described in detail, with reference to the accompanying drawings. Whenever possible like reference numerals have been used for like elements, and duplicative disclosure omitted. 
         [0019]    In general, a variable capacity rotary compressor is implemented such that a cooling capacity may be varied (for example, increased or decreased) according to environmental conditions so as to optimize an input-to-output ratio. One recent method utilizes an inverter motor adapted to a compressor to vary the cooling capacity of the compressor. However, in adapting the inverter motor to the compressor, the fabrication cost of the compressor is increased due to the high price of the inverter motor, thereby decreasing price competitiveness of the compressor. Thus, instead of adapting the inverter motor to the compressor, a technique is widely being researched, in which a refrigerant compressed in a cylinder of a compressor is partially bypassed to the exterior so as to vary a capacity of a compression chamber. However, this technique requires a complicated piping system to bypass the refrigerant out of the cylinder. Accordingly, a flow resistance of the refrigerant increases, thereby decreasing efficiency. As such, a method has been proposed, by which the piping system may be simplified without using the inverter motor and the compressor capacity may be varied. 
         [0020]    One (first) method allows pressure in an inner space at a cylinder to be changed or varied to a suction pressure or a discharge pressure. Accordingly, at a time of a power driving mode, the suction pressure is applied to the inner space of the cylinder and a vane normally performs a sliding motion, thereby forming a compression chamber. Conversely, at a time of a saving driving mode, the discharge pressure is applied to the inner space of the cylinder and the vane is retreated, thereby not forming the compression chamber (hereinafter this method will be referred to as “first variable capacity method”). 
         [0021]    Another (second) method is implemented such that a refrigerant of a suction pressure is only applied via an inlet and the suction pressure and the discharge pressure are alternately applied to a rear side of the vane. Accordingly, upon a power driving mode, the vane normally performs a sliding motion, thereby forming a compression chamber. Conversely, upon a saving driving mode, the vane is retreated, thereby not forming the compression chamber (hereinafter this method will be referred to as “second variable capacity method”). 
         [0022]    However, the two aforementioned methods must continuously restrict the vane, especially in a saving driving mode, in order to stabilize the system. Accordingly, vane restricting devices that restrict the vane must be utilized. 
         [0023]    For example, regarding the first variable capacity method, as shown in  FIG. 1 , a magnet  4  is provided at a rear side of a vane  3  disposed in a vane slot  2  of a cylinder  1 , or, as shown in  FIG. 2 , a back pressure switching valve  5  that supplies suction pressure is provided at the rear side of the vane  3 . Accordingly, the vane  3  is maintained in a retreated state. Reference numeral  6  denotes a rolling piston,  7  denotes a mode switching valve, and  8  denotes an inlet. 
         [0024]    In addition, regarding the second variable capacity method, as shown in  FIG. 3 , a lateral pressure passage  9  is disposed in the cylinder  1  to restrict the vane  3  by supplying a discharge pressure toward a lateral surface of the vane  3 . Reference numeral  10  denotes a vane chamber, and  11  denotes a back pressure switching valve. 
         [0025]    However, such vane restricting devices can not restrict the vane  3  at the same time when the operation mode of the compressor is switched, thereby lowering the performance of the compressor. In particular, vibration noise is generated by the vane  3 , which greatly increases compressor noise. For example, in the method of  FIG. 1 , in order to smoothly perform the compressor mode switching, large magnetism of the magnet  4  can not be applied. As a result, upon the saving driving mode of the compressor, the magnet  4  can not rapidly restrict the vane  3 , and thereby noise can be generated due to vane jumping. In the method of  FIG. 2 , on the other hand, upon the power driving mode of the compressor, a pressure at the rear side of the vane  3  can not rapidly be varied from a discharge pressure into a suction pressure, and thereby the vane  3  is not restricted at the same time of the mode switching. As a result, noise may be generated due to an impact between the rolling piston  6  and the vane  3 . Also, in the method of  FIG. 3 , a lateral force F 2  transferred to the vane  3  via the lateral pressure passage  9  is not sufficiently greater than a force F 1  due to pressure in the vane chamber  10 . Also, a pressure at the rear side of the vane  3  can not rapidly be varied from a discharge pressure into a suction pressure, and thereby the vane  3  is not restricted at the same time when the compressor mode switching. As a result, an impact occurs between the vane  3  and the rolling piston  6 , which makes noise. In particular, under a particular driving condition of the compressor, as shown in  FIG. 4 , when the compressor is switched from a power driving mode into a saving driving mode, excessive noise is generated for a certain time period t. 
         [0026]    Typically, rotary compressors may be classified into single type rotary compressors or double type rotary compressors according to a number of cylinders. For example, for a single type rotary compressor, one compression chamber is formed using a rotational force transferred from a motor. For a double type rotary compressor, a plurality of compression chambers having a phase difference of 180° therebetween are vertically formed, using a rotational force transferred from a motor. Hereinafter, explanation is given of a double type variable capacity rotary compressor in which a plurality of compression chambers are vertically formed, and a capacity of at least one of the compression chambers is varied. That is, a variable capacity double type rotary compressor according to an embodiment will be explained in detail with reference to the accompanying drawings. 
         [0027]      FIG. 5  is a longitudinal sectional view of a variable capacity rotary compressor according to an embodiment.  FIG. 6  is a horizontal sectional view showing a released state of a vane when the variable capacity rotary compressor of  FIG. 5  is in a power driving mode.  FIG. 7  is a horizontal sectional view showing a restricted state of a vane when the variable capacity rotary compressor of  FIG. 5  is in a saving driving mode.  FIG. 8  is an enlarged view showing in detail a process of restricting the vane of  FIG. 7 .  FIG. 9  is a graph showing noise characteristics at a time of a mode change of the variable capacity rotary compressor of  FIG. 5 . 
         [0028]    As shown in  FIG. 5 , a double type variable capacity rotary compressor  1  according to an embodiment may include a casing  100  having a hermetic space, a motor  200  which may be installed at an upper side of the casing  100  and that generates a constant speed rotational force or an inverter rotational force, a first compression device  300  and a second compression device  400  which may each be disposed at a lower side of the casing  100  and that compress a refrigerant by a rotational force generated from the motor  200 , and a mode switching device  500  that switches an operation mode such that the second compression device  400  performs a power driving mode or a saving driving mode. 
         [0029]    The hermetic space of the casing  100  may be maintained in a discharge pressure atmosphere by a refrigerant discharged from the first compression device  300  and the second compression device  400 . A first gas suction pipe SP 1  and a second gas suction pipe SP 2  may be respectively connected to a lower circumferential surface of the casing  100  so as to allow the refrigerant to be sucked into the first and second compression parts  300  and  400 . A gas discharge pipe DP may be connected to an upper end of the casing  100  such that the refrigerant discharged from the first and second compression devices  300  and  400  to the hermetic space may be transferred to a refrigeration system. 
         [0030]    The motor part  200  may include a stator  210  which may be installed in the casing  100  and that receives power from the exterior, a rotor  220  disposed in the stator  210  with a certain air gap therebetween and rotated by interaction with the stator  210 , and a rotational shaft  230  coupled to the rotor  220  that transmits a rotational force to the first compression device  300  and the second compression device  400 . 
         [0031]    The rotational shaft  230  may include a shaft portion  231  coupled to the rotor  220 , and a first eccentric portion  232  and a second eccentric portion  233  eccentrically disposed at both right and left sides below the shaft portion  231 . The first and second eccentric portions  232  and  233  may be symmetrically disposed by a phase difference of about 180° therebetween. The first and second eccentric portions  232  and  233  may be respectively rotatably coupled to a first rolling piston  340  and a second tolling piston  430  which will be explained later. 
         [0032]    The first compression device  300  and the second compression device  400  may be arranged at upper and lower sides of a lower portion of the casing  100 . The second compression device  400  which may be arranged at the lower end of the casing  100  may have a variable capacity. 
         [0033]    The first compression device  300  may include a first cylinder  310  having a ring shape and installed in the casing  100 , and an upper bearing plate  320  (hereafter, referred to as “upper bearing”) and a middle bearing plate  330  (hereafter, referred to as “middle bearing”) covering upper and lower sides of the first cylinder  310 , thereby forming a first compression space V 1 , that supports the rotational shaft  230  in a radial direction. A first rolling piston  340  may be rotatably coupled to an upper eccentric portion of the rotational shaft  230  and compresses the refrigerant by orbiting in the first compression space V 1  of the first cylinder  310 . A first vane  350  may be coupled to the first cylinder  310  to be movable in a radial direction so as to be in contact with an outer circumferential surface of the first rolling piston  340  that divides the first compression space V 1  of the first cylinder  310  into a first suction chamber and a first compression chamber. A vane supporting spring  360 , which may be formed of a compression spring, may elastically support a rear side of the first vane  350 . A first discharge valve  370  may be openably coupled to an end of a first discharge opening  321  disposed in a middle of the upper bearing  320  to control a discharge of a refrigerant gas discharged from the first compression chamber of the first compression space V 1 . Also, a first muffler  380  may be coupled to the upper bearing  320  and may have an inner volume to receive the first discharge valve  370 . 
         [0034]    The first cylinder  310 , as shown in  FIG. 5 , may include a first vane slot  311  formed at one side of an inner circumferential surface thereof constituting the first compression space V 1  for reciprocating the first vane  350  in a radial direction, a first inlet (not shown) formed at one side of the first vane slot  311  in a radial direction that introduces a refrigerant into the first compression space V 1 , and a first discharge guiding groove (not shown) inclinably installed at the other side of the first vane slot  311  in a shaft direction that discharges a refrigerant into the casing  100 . One of the upper bearing  320  and the middle bearing  330  may have a diameter shorter than that of the first cylinder  310  such that an outer end (or ‘rear end’ equally used hereinafter) of the first vane  350  may be supported by a discharge pressure of a refrigerant filled in the hermetic space of the casing  100 . 
         [0035]    The second compression device  400  may include a second cylinder  410  having a ring shape and installed at a lower side of the first cylinder  310  inside the casing  100 , and the middle bearing  330  and a lower bearing  420  covering both upper and lower sides of the second cylinder  410  to thereby form a second compression space V 2 , that support the rotational shaft  230  in a radial direction and a shaft direction. A second rolling piston  430  may be rotatably coupled to a lower eccentric portion of the rotational shaft  230  to compress a refrigerant by orbiting in the second compression space V 2  of the second cylinder  410 . A second vane  440  may be movably coupled to the second cylinder  410  in a radial direction so as to be in contact with or be spaced apart from an outer circumferential surface of the second rolling piston  430 , to divide the second compression space V 2  of the second cylinder  410  into a second suction chamber and a second compression chamber or that connects the second suction chamber to the second compression chamber. A second discharge valve  450  may be openably coupled to an end of a second discharge opening  421  provided in the middle of the lower bearing  420  to control a discharge of a refrigerant discharged from the second compression chamber. A second muffler  460  may be coupled to the lower bearing  420  and may have a certain inner volume to receive the second discharge valve  450 . 
         [0036]    The second compression space V 2  of the second cylinder  410  may have the same or a different capacity from the first compression space V 1  of the first cylinder  310 , if necessary. For example, where the two cylinders  310  and  410  have the same capacity, when the second cylinder  410  is driven in a saving driving mode, the compressor may be driven with a capacity corresponding to the capacity of another cylinder (for example, the first cylinder  310 ), and thus, a function of the compressor may be varied up to 50%. On the other hand, where the two cylinders  310  and  410  have different capacities, the function of the compressor may be varied into a ratio corresponding to a capacity of a cylinder that performs power driving. 
         [0037]    The second cylinder  410 , as shown in  FIGS. 5 to 7 , may include a second vane slot  411  formed at one side of an inner circumferential surface thereof constituting the second compression space V 2  that allows the second vane  440  to reciprocate in a radial direction, a second inlet  412  formed at one side of the second vane slot  411  in a radial direction that introduces a refrigerant into the second compression space V 2 , and a second discharge guiding groove (not shown) inclinably formed at the other side of the second vane slot  411  in a shaft direction that discharges a refrigerant into the casing  100 . Also, a vane chamber  413  may be hermetically formed at a rear side of the second vane slot  411 , and may be connected to a common side connection pipe  530  of a mode switching device  500  to be explained later. The vane chamber  413  may also be separated from the hermetic space of the casing  100  so as to maintain the rear side of the second vane  440  as a suction pressure atmosphere or a discharge pressure atmosphere. A high pressure passage  414  that connects the inside of the casing  100  to the second vane slot  411  in a perpendicular direction or an inclined direction to a motion direction of the second vane  440  and thereby restricts the second vane  440  by a discharge pressure inside the casing  100  is formed at the second cylinder  440 . A low pressure passage  415  that connects the second vane slot  411  to the second inlet  412  to generate a pressure difference with the high pressure passage  414  so as to quickly restrict the second vane  440  may be formed at an opposite side to the high pressure passage  414 . 
         [0038]    The vane chamber  413  connected to the common side connection pipe  530  to be explained later may have a certain inner volume. Accordingly, even if the second vane  440  has been completely moved backward so as to be received inside the second vane slot  411 , the rear surface of the second vane  440  may have a pressure surface for a pressure supplied through the common side connection pipe  530 . The high pressure passage  414 , as shown in  FIGS. 5 and 6 , may be positioned at a side of the discharge guiding groove (not shown) of the second cylinder  410  based on the second vane  440 , and may be penetratingly formed toward a center of the second vane slot  411  from an outer circumferential surface of the second cylinder  410 . 
         [0039]    The high pressure passage  414  may be formed to have a two-step narrowly formed towards the second vane slot  411  using a two-step drill. An outlet of the high pressure passage  414  may be formed at an approximate middle part of the second vane slot  411  in a longitudinal direction so that the second vane  440  may perform a stable linear reciprocation. A sectional area of the high pressure passage  414  may be equal to or narrower than a pressure surface applied to a rear surface of the second vane  440  via the vane chamber, that is, a sectional area of the second vane slot  411 , thereby preventing the second vane  440  from being excessively restricted. 
         [0040]    Although not shown in the drawings, the high pressure passage  414  may be recessed a certain depth in both upper and lower side surfaces of the second cylinder  410 , or may be recessed by a certain depth in the lower bearing  420  or the middle bearing  330 , respectively, coupled to both side surfaces of the second cylinder  410  or formed through the lower bearing  420  or the middle bearing  330 . If the high pressure passage  414  is recessed at an upper surface either of the lower bearing  420  or of the middle bearing  330 , it may be formed at the same time that the second cylinder  410  or each bearing  420  and  330  is processed, for example, by sintering, to reduce fabrication cost. 
         [0041]    The low pressure passage  415  may be arranged on the same line with the high pressure passage  414  such that a pressure difference between a discharge pressure and a suction pressure may be generated at both side surfaces of the second vane  440 , thereby allowing the second vane  440  to come in contact with the second vane slot  411 . However, the low pressure passage  415  may be formed on a parallel line with the high pressure passage  414  or at an angle thereto so as to be crossed with the high pressure passage  414 . 
         [0042]    The low pressure passage  415 , as shown in  FIG. 8 , may be positioned to be connected to the vane chamber  413  by a gap between the second vane  440  and the second vane slot  411  when the compressor is in a saving driving mode. However, if the second vane  440  is moved forward while the compressor is in a power driving mode, when the low pressure passage  415  is connected to the vane chamber  413 , a discharge pressure Pd filled in the vane chamber  413  may be leaked to the second inlet  412  into which a refrigerant of a suction pressure is introduced. Accordingly, the second vane  440  may not be satisfactorily supported. Hence, the low pressure passage  415  may be formed to be positioned within a reciprocating range of the second vane  440 . 
         [0043]    Although not shown in the drawings, a plurality of each of the high pressure passage  414  and the low pressure passage  415  may be formed along a height direction of the second vane  440 . The sectional areas of the high pressure passage  414  and the low pressure passage  415  may be the same or different. 
         [0044]    The mode switching device  500  may include a low pressure side connection pipe  510  diverged from a second gas suction pipe SP 2 , a high pressure side connection pipe  520  connected into an inner space of the casing  100 , a common side connection pipe  530  connected to the vane chamber  413  of the second cylinder  410  and alternately connected to both the low pressure side connection pipe  510  and the high pressure side connection pipe  520 , a first mode switching valve  540  connected to the vane chamber  413  of the second cylinder  410  via the common side connection pipe  530 , and a second mode switching valve  550  connected to the first mode switching valve  540  that controls an opening/closing operation of the first mode switching valve  540 . The low pressure side connection pipe  510  may be connected between a suction side of the second cylinder  410  and an inlet side gas suction pipe of an accumulator  110 , or between the suction side of the second cylinder  410  and an outlet side gas suction pipe (second gas suction pipe SP 2 ). 
         [0045]    The high pressure side connection pipe  520  may be connected to a lower portion of the casing  100 , thereby to directly introduce oil within the casing  100  into the vane chamber  413 , or may be diverged from a middle part of a gas discharge pipe DP. Herein, as the vane chamber  413  becomes hermetic, oil may not be supplied between the second vane  440  and the second vane slot  411 , which may generate a frictional loss. Accordingly, an oil supply hole (not shown) may be formed at the lower bearing  420  such that the oil may be supplied when the second vane  440  performs a reciprocating motion. 
         [0046]    An operational of a double type variable capacity rotary compressor according to an embodiment disclosed herein will be described as follows. 
         [0047]    That is, when the rotor  220  is rotated as power is applied to the stator  210  of the motor  200 , the rotational shaft  230  is rotated together with the rotor  220 . A rotational force of the motor  200  is transferred to the first compression device  300  and the second compression device  400 . Depending on a capacitance of an air conditioner, both the first and second compression devices  300  and  400  may be normally driven (for example, in a power driving mode) so as to generate a cooling capacity of a large capacitance, or the first compression device  300  may perform a normal driving and the second compression device  400  may perform a saving driving, so as to generate a cooling capacity of a small capacitance. 
         [0048]    In the case where the compressor or an air conditioner having the same is in a power driving mode, as shown in  FIG. 5 , power is applied to the second mode switching valve  550 . Accordingly, the low pressure side connection pipe  510  may be blocked while the high pressure side connection pipe  520  is connected to the common side connection pipe  530 . Gas of high pressure or oil of high pressure within the casing  100  may be supplied to the vane chamber  413  of the second cylinder  410  via the high pressure side connection pipe  520 , and thereby the second vane  440  may be retreated by a pressure of the vane chamber  413 . As a result, the second vane  440  may be maintained in a state of being in contact with the second rolling piston  430  and normally compresses refrigerant gas introduced into the second compression space V 2  and then discharges the compressed refrigerant gas. 
         [0049]    At this time, a refrigerant or oil of high pressure may be supplied into the high pressure passage  414  formed in the second cylinder  410  or the bearing  430  or  420 , to thereby pressurize one side surface of the second vane  440 . However, since the sectional area of the high pressure passage  414  is smaller than that of the second vane slot  411 , a pressurizing force of the vane chamber  413  in a lateral direction may be smaller that a pressurizing force of the vane chamber  413  in backward and forward directions. As a result, the second vane  440  may not be restricted. 
         [0050]    As such, the first vane  350  and the second vane  440  may be respectively in contact with the rolling pistons  340  and  440 , to thereby divide the first compression space V 1  and the second compression space V 2  into a suction chamber and a compression chamber. As the first vane  310  and the second vane  440  compress each refrigerant sucked into each suction chamber and then discharge the compressed refrigerant. As a result, the compressor or the air conditioner having the same may perform a driving of 100%. 
         [0051]    On the other hand, when the compressor or an air conditioner having the same is in a saving driving mode, as shown in  FIG. 7 , the mode switching valve  510  may be operated in an opposite way to the normal (power) driving, to thereby connect the low pressure side connection pipe  510  to the common side connection pipe  530 . As a result, a refrigerant of a low pressure sucked into the second cylinder  410  may be partially introduced into the vane chamber  413 . Accordingly, the second vane  440  may be retreated by a pressure of the second compression space V 2  to be received inside the second vane slot  411 , and thus, the suction chamber and the compression chamber of the second compression space V 2  may be connected to each other. Thus, the refrigerant sucked into the second compression space V 2  may not be compressed. 
         [0052]    Here, a pressure difference applied onto both side surfaces of the second vane  440  may be increased by the high pressure passage  414  and the low pressure passage  415  formed in the second cylinder  410  or the bearing  330  or  420 . Accordingly, the second vane  440  may be efficiently and rapidly restricted. For example, as shown in  FIGS. 7 and 8 , oil or refrigerant at the high pressure may be introduced into the high pressure passage  414  and simultaneously refrigerant or oil at a discharge pressure remaining in the vane chamber  413  may be leaked into a gap between the second vane  440  and the vane slot  411  and to the second inlet  412  through the low pressure passage  415 . Accordingly, when the operation mode of the compressor is switched, the second vane  440  may be restricted more rapidly. In particular, when the compressor is switched from the power driving mode into the saving driving mode, if a discharge pressure Pd filled in the vane chamber  413  is not quickly discharged therefrom, a restriction force F 2  transferred to the second vane  440  via the high pressure passage  414  may not be much greater than a supporting force F 1  transferred to the second vane  440  from the vane chamber  413  which may have a relatively large pressurized area due to the small sectional area of the high pressure passage  414 , thereby making the second vane move unstably. However, if the low pressure passage  415  connected to the second inlet  412  is formed at the opposite side to the high pressure passage  414 , the discharge pressure Pd remaining in the vane chamber  413  may be changed into a middle pressure Pm and then rapidly leaked through the low pressure passage  415 . Accordingly, the supporting force F 1  at the vane chamber  413  may be drastically decreased, so as to allow the second vane  440  to be rapidly restricted. 
         [0053]    Test results are shown in  FIG. 9 . That is, it can be noted from  FIG. 9  that no peak noise, which was generated for approximately 2.5 seconds when the power driving mode is switched to the driving saving mode, as shown in  FIG. 4 , is generated. 
         [0054]    As such, as the compression chamber and the suction chamber of the second cylinder  410  are connected to each other, refrigerant sucked into the suction chamber of the second cylinder  410  may not be compressed but rather re-moved into the suction chamber along a locus of the second rolling piston  430 . Accordingly, the second compression device  400  may not compress the refrigerant, and thus the compressor or the air conditioner having the same performs a driving corresponding to only the capacity of the first compression device  300 . 
         [0055]    The vane restricting method according to embodiments disclosed herein may be applied to another variable capacity rotary compressor. That is, in the aforementioned embodiment, in the case of supplying a refrigerant at a suction pressure Ps into the inlet  412  at any time regardless of the operation mode of the compressor, the vane chamber  413  may be connected to the inlet  412 , so that the discharge pressure Pd of the vane chamber  413  may be rapidly leaked to the inlet  412  when the power driving mode is switched into the saving driving mode. However, in the embodiments shown in  FIGS. 10 and 11 , a refrigerant switching valve  600  may be further provided at a gas suction pipe (not shown) connected to the inlet  412  such that a refrigerant of the suction pressure Ps or the discharge pressure Pd may selectively be supplied to the inlet  412  depending on the operation mode. With this configuration, at the time of the saving driving mode, the refrigerant of the discharge pressure Pd may be introduced into the second compression space V 2  of the second cylinder  410  via the inlet  412 , and thereby the second vane  440  may be retreated to be restricted accordingly. 
         [0056]    In this case, as shown in  FIG. 10 , it may be implemented that either the discharge pressure Pd or the suction pressure Ps may selectively be supplied to the rear side of the second vane  440  depending on the operation mode of the compressor. In the alternative, as shown in  FIG. 11 , it may be implemented that the discharge pressure Pd may always be supplied to the rear side of the second vane  440 . 
         [0057]    For example, in the embodiment of  FIG. 10 , a vane chamber  413  separated from the hermetic space of the casing  100  may be formed at the rear side of the second vane  440 , and a back pressure switching valve  700  that selectively supplies either a suction pressure or a discharge pressure according to the operation mode of the compressor may be connected to the vane chamber  413 . Also, in the embodiment of  FIG. 11 , the hermetic space of the casing  100  may be connected to an outer surface of the second vane slot  411 , and a vane restricting device  800 , such as a magnet or a tensile spring, may be disposed at an outer circumferential surface of the second vane slot  411 . 
         [0058]    Even in the above embodiments, the high pressure passage  414  and the low pressure passage  415  may be connected to both sides of the second vane slot  411 . Accordingly, at the time of the saving driving mode, the second vane  440  may be effectively restricted by a pressure difference between the high pressure passage  414  and the low pressure passage  415 . However, in these embodiments, at the time of the saving driving mode, since the refrigerant of the discharge pressure Pd may be introduced via the second inlet  412 , the high pressure passage  414 , unlike in the aforementioned embodiment, may be formed between the second inlet  412  and the second vane slot  411 , while the low pressure passage  415  may be formed to be connected to a suction pressure side connection pipe (not shown) provided at an outer surface of the casing  100  from the opposite side to the high pressure passage  414 . 
         [0059]    An exemplary double type rotary compressor has been described according to the embodiments disclosed herein, but embodiments may equally be applied to a single type rotary compressor. Also, it may equally be applied to every compression device of the double type rotary compressor, explanations all of which are similar to those of the aforementioned embodiments, and thus are not repeated herein. 
         [0060]    A variable capacity rotary compressor according to embodiments disclosed herein has numerous applications in which compression of fluid is required. Such application may include, for example, air conditioning and refrigeration applications. One such exemplary application is shown in  FIG. 12 , in which, a compressor  1710  according to embodiments disclosed herein is installed in a refrigerator/freezer  1700 . Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,082,776, 6,955,064, 7,114,345, 7,055,338, and 6,772,601, the entirety of which are incorporated herein by reference. 
         [0061]    Another such exemplary application is shown in  FIG. 13 , in which a compressor  1810  according to embodiments disclosed herein is installed in an outdoor unit of an air conditioner  1800 . Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,121,106, 6,868,681, 5,775,120, 6,374,492, 6,962,058, and 5,947,373, the entirety of which are incorporated herein by reference. 
         [0062]    Another such exemplary application is shown in  FIG. 14 , in which a compressor  1910  according to embodiments disclosed herein is installed in a single, integrated air conditioning unit  1900 . Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,032,404, 6,412,298, 7,036,331, 6,588,228, 6,182,460, and 5,775,123, the entireties of which is incorporated herein by reference. 
         [0063]    Embodiments disclosed herein provide a variable capacity rotary compressor capable of greatly reducing noise due to an impact between a vane and a rolling piston by rapidly restricting the vane at a time of switching a compressor mode. 
         [0064]    According to embodiments disclosed herein, as embodied and broadly described herein, there is provided a capacity-variable rotary compressor in which a rolling piston performs an eccentric orbiting motion in an inner space of a hermetic cylinder assembly, a vane performs a linear movement in a radial direction by contacting the rolling piston thereby to divide the inner space into a compression chamber and a suction chamber, and then the vane is restricted by a difference of pressure applied thereto at a time of a saving driving. 
         [0065]    According to embodiments disclosed herein, there is also provided a capacity-variable rotary compressor that includes a cylinder assembly installed in a hermetic casing and including a compression space in which a refrigerant is sucked to be compressed, an inlet connected to the compression space, and a vane slot formed at one side of the inlet, a rolling piston for transferring the refrigerant with performing an eccentric orbiting motion inside the compression space of the cylinder assembly, a vane slidibly inserted into the vane slot of the cylinder assembly, having an inner end coming in contact with the rolling piston so as to divide the compression space into a suction chamber and a compression chamber, and a mode switching unit for contacting or separating the vane with/from the rolling piston depending on an operation mode of the compressor, wherein a suction pressure is applied onto one side surface of the vane and a discharge pressure is applied onto the other side of the vane such that the vane can be in contact with the vane slot to thusly be restricted when the compressor performs a saving driving. 
         [0066]    Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
         [0067]    Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.