Patent Publication Number: US-2023143495-A1

Title: Compressor

Description:
TECHNICAL FIELD 
     The present disclosure relates to a compressor. More specifically, the present disclosure relates to a scroll compressor in which an external oil supply structure is applied such that oil may be efficiently supplied. 
     BACKGROUND ART 
     In general, a compressor, as a device applied to a refrigeration cycle (hereinafter, abbreviated as the refrigeration cycle) such as a refrigerator or an air conditioner, is a device that compresses a refrigerant so as to perform an operation necessary for a heat exchange to occur in the refrigeration cycle. 
     The compressors may be divided into a reciprocating compressor, a rotary compressor, a scroll compressor, and the like based on a scheme of compressing the refrigerant. Among them, the scroll compressor is a compressor that forms a compression chamber between a fixed wrap of a fixed scroll and an orbiting wrap of an orbiting scroll as the orbiting scroll is engaged with and orbits the fixed scroll fixed in an inner space of a sealed container. 
     Because the scroll compressor is continuously compressed via shapes of scrolls in engagement with each other, the scroll compressor may obtain a relatively high compression ratio compared to other types of compressors. In addition, because suction, compression, and discharge strokes of the refrigerant are smooth, the scroll compressor may obtain a stable torque. For this reason, the scroll compressor is widely used for refrigerant compression in the air conditioner and the like. 
     Referring to Japanese Patent No. 6344452, a conventional scroll compressor includes a casing that forms an outer appearance of the compressor and has a discharge port through which a refrigerant is discharged, compressing portion fixed to the casing so as to compress the refrigerant, and a driver fixed to the casing and driving the compressing portion, and the compressing portion and the driver are connected to each other by a rotating shaft coupled to the driver and rotating. 
     The compressing portion includes a fixed scroll fixed to the casing and having a fixed wrap, and an orbiting scroll including an orbiting wrap driven in engagement with the fixed wrap by the rotating shaft. In such conventional scroll compressor, the rotating shaft is eccentric and the orbiting scroll rotates by being fixed to the eccentric rotating shaft. Therefore, the orbiting scroll compresses the refrigerant while orbiting along the fixed scroll. 
     In such a conventional scroll compressor, it is common that the compressing portion is disposed below the discharge port and the driver is disposed below the compressing portion. One end of the rotating shaft is coupled to the compressing portion, and the other end thereof extends through the driver. 
     In the conventional scroll compressor, because the compressing portion is disposed above the driver and is disposed close to the discharge port, it was difficult to supply oil to the compressing portion. In addition, there was a disadvantage that a lower frame is additionally needed to separately support the rotating shaft connected to the compressing portion from a position below the driver. In addition, the conventional scroll compressor had a problem in that an efficiency and a reliability are lowered as the scroll tilts because action points of a gas force generated by the refrigerant inside the compressor and a reaction force supporting the same do not coincide with each other. 
     In order to solve such problem, referring to Korean Patent Application Publication No. 10-2018-0124636, recently, a scroll compressor in which the driver is located below the discharge port and the compressing portion is located below the driver has appeared (as known as a lower scroll compressor). 
     In the lower scroll compressor, the driver is closer to the discharge port than the compressing portion, and the compressing portion is disposed farthest apart from the discharge port. 
     In such lower scroll compressor, one end of the rotating shaft may be connected to the driver and the other end thereof may be supported by the compressing portion, so that the lower frame may be omitted, and the oil stored in the lower portion of the casing lower may be directly supplied to the compressing portion without passing through the driver. In addition, when the rotating shaft extends through and is connected to the compressing portion in the lower scroll compressor, the action points of the gas force and the reaction force may coincide with each other on the rotating shaft to offset the vibration or the overturning moment of the scroll, thereby ensuring efficiency and reliability. 
     In one example, Patent Document 1 discloses a propeller and an oil pickup of a sealed compressor. The oil stored in the lower portion may be supplied using a centrifugal force. However, a structure in which a portion of an oil supply passage is disposed outside the compressor is not disclosed. Therefore, there is a problem that the oil is not able to be optimally supplied based on conditions of the compressor. 
     Patent Document 2 discloses a differential pressure oil supply structure and a pressure reducing pin in the lower scroll compressor. The oil stored in the lower portion may be supplied using a differential pressure. However, the structure in which the portion of the oil supply passage is disposed outside the compressor is not disclosed. Therefore, there is the problem that the oil is not able to be optimally supplied based on the conditions of the compressor. 
     DISCLOSURE 
     Technical Problem 
     According to the present embodiment, the present disclosure is to provide a compressor in which a portion of a passage to which oil is supplied is disposed outside such that the oil may be efficiently supplied. 
     In addition, the present disclosure is to provide a compressor that may adjust an amount of oil flowing in a passage to which the oil is supplied based on an operating pressure. 
     In addition, the present disclosure is to provide a compressor that may identify a line clogging phenomenon of a passage to which oil is supplied. 
     In addition, the present disclosure is to provide a compressor that may efficiently supply oil even when a line clogging phenomenon occurs in a passage to which oil is supplied. 
     In addition, the present disclosure is to provide a compressor in which a portion to which oil is supplied varies based on an operating pressure. 
     In addition, the present disclosure is to provide a compressor that may change a passage to which oil is supplied based on an operating pressure. 
     Technical Solutions 
     As an example for solving the above problems, it is to provide a compressor in which a portion of an oil supply passage extends to the outside of a casing, so that oil is supplied to compressing portion via the outside of the casing. In addition, it is to provide a compressor in which a plurality of passages through which the oil is supplied from the outside to the compressing portion or a suction port are arranged. In addition, it is to provide a compressor having a flow rate adjusting valve, a pressure sensor, and passage adjusting portion. 
     Specifically, according to the present embodiments, a compressor may include a casing having a suction port for a refrigerant to be introduced into the compressor, a discharge port for discharging the refrigerant, and a storage space for storing oil therein, a driver coupled to an inner circumferential surface of the casing, a rotating shaft coupled to the driver and rotating and constructed to supply the oil, and compressing portion coupled to the rotating shaft to compress the refrigerant and lubricated with the oil. 
     The compressing portion may include an orbiting scroll coupled to the rotating shaft to perform an orbital motion when the rotating shaft rotates, a fixed scroll disposed in engagement with the orbiting scroll, wherein the fixed scroll receives the refrigerant and compresses and discharges the refrigerant, and a main frame including a main end plate for accommodating the orbiting scroll therein and a main side plate connected to the fixed scroll. 
     The rotating shaft may include an oil feeder for collecting the oil stored in the oil storage space by extending through the fixed scroll, and an oil supply passage extending along a longitudinal direction of the rotating shaft to transfer the oil supplied from the oil feeder. 
     It is to provide a compressor including a first passage in communication with the oil supply passage so as to allow the oil to flow, a second passage extending from the first passage and constructed such that the oil is able to flow outside of the casing, a third passage extending from the second passage and disposed outside the casing, and a main passage extending from the third passage and extending through the fixed scroll or the main frame. 
     In addition, it is to provide a compressor in which the fixed scroll includes a fixed end plate disposed on a side of the main end plate far from the driver and coupled to the casing to form the other surface of the compressing portion, a fixed side plate extending from the fixed end plate toward the discharge port and in contact with the main side plate, and a fixed wrap positioned closer to the rotating shaft than the fixed side plate and protruding in a direction of the discharge port from the fixed end plate, wherein the fixed wrap forms a compression chamber where the refrigerant is compressed, wherein one of the main side plate, the fixed end plate, and the fixed side plate includes a first inflow portion extending through one of the main side plate, the fixed end plate, and the fixed side plate such that the oil is supplied to a space between the fixed scroll and the orbiting scroll from the main passage. 
     In addition, it is to provide a compressor including a second inflow portion positioned farther from the rotating shaft than the first inflow portion and extending through one of the main side plate, the fixed end plate, and the fixed side plate, and a first branched passage branched from the main passage and constructed such that the oil is supplied to the space between the fixed scroll and the orbiting scroll via the second inflow portion. 
     In addition, it is to provide a compressor in which the first inflow portion and the second inflow portion are disposed on opposite sides with respect to the rotating shaft. 
     In addition, it is to provide a compressor including a second branched passage branched from the main passage and constructed such that the oil is supplied to the suction port located farther from the rotating shaft than the first inflow portion. 
     In addition, it is to provide a compressor including passage adjusting portion disposed in a portion branching from the main passage to the first branched passage to change a passage such that the oil flows to the main passage or the first branched passage based on an operating pressure. 
     In addition, it is to provide a compressor in which the passage adjusting portion is disposed outside the casing. 
     In addition, it is to provide a compressor in which the passage adjusting portion is constructed to allow the oil to flow to the main passage when the operating pressure is equal to or higher than a reference value and to allow the oil to flow to the first branched passage when the operating pressure is lower than the reference value. 
     In addition, it is to provide a compressor in which the passage adjusting portion is formed as a three-way valve. 
     In addition, it is to provide a compressor including passage adjusting portion disposed in a portion branching from the main passage to the second branched passage to change a passage such that the oil flows to the main passage or the second branched passage based on an operating pressure. 
     In addition, it is to provide a compressor in which the passage adjusting portion is disposed outside the casing. 
     In addition, it is to provide a compressor in which the passage adjusting portion is constructed to allow the oil to flow to the main passage when the operating pressure is equal to or higher than a reference value and to allow the oil to flow to the second branched passage when the operating pressure is lower than the reference value. 
     In addition, it is to provide a compressor in which the passage adjusting portion is formed as a three-way valve. 
     In addition, it is to provide a compressor in which the second passage extends through the rotating shaft, the main end plate, and the casing. 
     In addition, it is to provide a compressor including a flow rate adjusting valve disposed on the third passage or the main passage, wherein an opening and closing rate of the flow rate adjusting valve is adjusted based on an amount of oil flowing into the third passage or the main passage. 
     In addition, it is to provide a compressor including a pressure sensor located rearwardly of the flow rate adjusting valve and in communication with the third passage or the main passage, wherein the pressure sensor measures a pressure of the third passage or the main passage. 
     In addition, it is to provide a compressor in which the flow rate adjusting valve is disposed outside the casing. 
     In addition, it is to provide a compressor in which the pressure sensor is disposed outside the casing. 
     Advantageous Effects 
     According to the embodiments of the present disclosure, the portion of the oil passage may be disposed outside of the compressor, so that the oil may be efficiently supplied to the rotating shaft and the compressing portion when the operating pressure is the high-pressure. 
     In addition, the plurality of passages to which the oil is supplied may be arranged to increase the oil supply efficiency. 
     In addition, the oil supply efficiency may be maximized as the passage through which the oil is supplied may be changed based on the operating pressure. 
     In addition, as the flow rate adjusting valve is disposed, the optimum amount of oil required for each condition based on the operating speed, the operating pressure, and the like may be supplied. 
     In addition, as the pressure sensor is disposed, the clogging of the oil passage may be identified, and accordingly, the opening and closing rate of the valve may be adjusted to secure the reliability of the passage. 
     In addition, when the oil passage clogging occurs, the oil may be supplied by changing the passage to which the oil is supplied, thereby securing the reliability of the passage. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view showing a basic configuration and an oil passage of a lower scroll compressor according to an embodiment of the present disclosure. 
         FIG.  2    is a view showing that a portion of an oil passage is disposed outside and a main passage is constructed such that oil may be supplied to a compressing portion, according to an embodiment of the present disclosure. 
         FIG.  3    is a view showing a first branched passage branched from a main passage according to an embodiment of the present disclosure. 
         FIG.  4    is a view showing a second branched passage branched from a main passage according to an embodiment of the present disclosure. 
         FIG.  5    is a view showing passage adjusting portion disposed between a main passage and a first branched passage and constructed such that a passage may be changed, according to an embodiment of the present disclosure. 
         FIG.  6    is a view showing passage adjusting portion disposed between a main passage and a second branched passage and constructed such that a passage may be changed, according to an embodiment of the present disclosure. 
         FIG.  7    is a view showing a flow rate adjusting valve and a pressure sensor according to an embodiment of the present disclosure. 
         FIG.  8    is a view showing a first branched passage, a flow rate adjusting valve, a pressure sensor, and passage adjusting portion according to an embodiment of the present disclosure. 
         FIG.  9    is a view showing a second branched passage, a flow rate adjusting valve, a pressure sensor, and passage adjusting portion according to an embodiment of the present disclosure. 
     
    
    
     BEST MODE 
     Hereinafter, a specific embodiment of the present disclosure will be described with reference to the drawings. Following detailed description is provided to provide a comprehensive understanding of a method, an apparatus, and/or a system described herein. However, this is merely an example and the present disclosure is not limited thereto. 
     In describing embodiments of the present disclosure, when it is determined that a detailed description of a known technology related to the present disclosure may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. In addition, terms to be described later, as terms defined in consideration of functions thereof in the present disclosure, may vary based on intentions of users and operators or customs. Therefore, the definition thereof should be made based on the content throughout this specification. Terms used in the detailed description are for illustrating the embodiments of the present disclosure only, and should not be restrictive. Unless explicitly used otherwise, the singular expression includes the plural expression. Herein, expressions such as “comprising” or “including” are intended to indicate certain features, numbers, steps, operations, elements, and some or combinations thereof, and should not be construed to exclude a presence or a possibility of one or more other features, numbers, steps, operations, elements, or some or combinations thereof other than those described. 
       FIG.  1    shows a structure of a lower scroll compressor according to an embodiment of the present disclosure. Specifically,  FIG.  1    shows an internal structure and an oil supply structure of a lower scroll compressor  10 . 
     Referring to  FIG.  1   , a scroll compressor  10  may include a casing  100  having a space in which a fluid is stored or flows defined therein, a driver  200  coupled to an inner circumferential surface of the casing  100  to rotate a rotating shaft  230 , and a compressing portion  300  disposed inside the casing and coupled to the rotation shaft  230  so as to compress the fluid. 
     Specifically, the casing  100  may have a discharge port  121  through which a refrigerant is discharged at one side thereof. The casing  100  may include an accommodating shell  110  formed in a cylindrical shape so as to accommodate the driver  200  and the compressing portion  300  therein, a discharge shell  120  coupled to one end of the accommodating shell  110  and equipped with the discharge port  121 , and a blocking shell  130  coupled to the other end of the accommodating shell  110  so as to seal the accommodating shell  110 . In addition, the casing  100  may include a suction port  111  through which the refrigerant is introduced at on one side of the accommodating shell  110 . 
     The driver  200  may include a stator  210  for generating a rotating magnetic field, and a rotor  220  constructed to rotate by the rotating magnetic field, and the rotating shaft  230  may be coupled to the rotor  220  to rotate together with the rotor  220 . 
     The stator  210  may have multiple slots defined along a circumferential direction in an inner circumferential surface thereof and a coil wound in the slots, and may be fixed to an inner circumferential surface of the accommodating shell  110 . The rotor  220  may be coupled with a permanent magnet and disposed inside the stator  210  and rotatably coupled to the stator  210  so as to generate rotational power. The rotating shaft  230  may be press-fitted into a center of the rotor  220  and coupled to the rotor  220 . 
     The compressing portion  300  may include a fixed scroll  320  coupled to the accommodating shell  110  and disposed on a side of the driver  200  far from the discharge port  121 , an orbiting scroll  330  coupled to the rotating shaft  230  and engaged with the fixed scroll  320  so as to form a compression chamber, and a main frame  310  that accommodates the orbiting scroll  330  therein and is seated on the fixed scroll  320  to form an outer appearance of the compressing portion  300 . 
     As a result, in the lower scroll compressor  10 , the driver  200  is disposed between the discharge port  121  and the compressing portion  300 . In other words, the driver  200  may be disposed on one side of the discharge port  121 , and the compressing portion  300  may be disposed on the side of the driver  200  far from the discharge port  121 . For example, when the discharge port  121  is disposed at an upper portion of the casing  100 , the compressing portion  300  may be disposed at a lower portion of the driver  200 , and the driver  200  may be disposed between the discharge port  120  and the compressing portion  300 . 
     Accordingly, when oil is stored on a bottom surface of the casing  100 , the oil may be directly supplied to the compressing portion  300  without passing through the driver  200 . In addition, because the rotating shaft  230  is coupled to and supported by the compressing portion  300 , a separate lower frame for rotatably supporting the rotating shaft separately may be omitted. 
     In one example, the lower scroll compressor  10  according to the present disclosure may be constructed such that the rotating shaft  230  passes through the orbiting scroll  330  as well as the fixed scroll  320  and is in surface contact with both the orbiting scroll  330  and the fixed scroll  320 . 
     Therefore, an inflow force generated when the fluid such as the refrigerant flows into the compressing portion  300 , a gas force generated when the refrigerant is compressed inside the compressing portion  300 , and a reaction force supporting the same may act on the rotating shaft  230  as it is. Accordingly, the inflow force, the gas force, and the reaction force may be applied to one action point on the rotating shaft  230 . Accordingly, because an overturning moment does not act on the orbiting scroll  330  coupled to the rotating shaft  230 , the orbiting scroll may be fundamentally blocked from tilting or overturning. In other words, up to axial vibration of the vibration occurring in the orbiting scroll  330  may be attenuated or prevented, and the overturning moment of the orbiting scroll  330  may also be attenuated or suppressed. Therefore, noise and vibration generated by the lower scroll compressor  10  may be blocked. 
     In addition, because the fixed scroll  320  is in surface contact with and supports the rotating shaft  230 , even when the input force and the gas force act on the rotating shaft  230 , durability of the rotating shaft  230  may be reinforced. 
     In addition, the rotating shaft  230  may partially absorb a discharge pressure generated as the refrigerant is discharged to the outside, thereby reducing a force (a normal force) allowing the orbiting scroll  330  and the fixed scroll  320  to be in close contact with each other excessively in an axial direction. As a result, a friction force between the orbiting scroll  330  and the fixed scroll  230  may also be greatly reduced. 
     As a result, the compressor  10  may attenuate the shaking in the axial direction and the overturning moment of the orbiting scroll  330  inside the compressing portion  300 , and reduce the friction force of the orbiting scroll, thereby improving an efficiency and a reliability of the compressing portion  300 . 
     In one example, the main frame  310  of the compressing portion  300  may include a main end plate  311  disposed on one side of the driver  200  or at a lower portion of the driver  300 , a main side plate  312  extending in a direction away from the driver  200  from an inner circumferential surface of the main head plate  311  and seated on the fixed scroll  320 , and a main shaft accommodating portion  318  extending from the main head plate  311  so as to rotatably support the rotating shaft  230 . 
     A main hole for guiding the refrigerant discharged from the fixed scroll  320  to the discharge port  121  may be further defined in the main end plate  311  or the main side plate  312 . 
     The main end plate  311  may further include an oil pocket  314  defined in a concave shape outwardly of the main shaft accommodating portion  318 . The oil pocket  314  may be defined in an annular shape, and may be defined so as to be eccentric from the main shaft accommodating portion  318 . The oil pocket  314  may be defined such that, when the oil stored in the blocking shell  130  is transmitted via the rotating shaft  230  and the like, the oil may be supplied to a portion where the fixed scroll  320  and the orbiting scroll  330  are engaged with each other. 
     The fixed scroll  320  may include a fixed end plate  321  disposed on a side of the main end plate  311  far from the driver  300  and coupled to the accommodating shell  110  so as to form the other surface of the compressing portion  300 , a fixed side plate  322  extending from the fixed end plate  321  toward the discharge port  121  and in contact with the main side plate  312 , and a fixed wrap  323  disposed on an inner circumferential surface of the fixed side plate  322  so as to form the compression chamber in which the refrigerant is compressed. 
     In one example, the fixed scroll  320  may include a fixed through-hole  328  defined such that the rotating shaft  230  passes therethrough, and a fixed shaft accommodating portion  3281  extending from the fixed through-hole  328  so as to rotatably support the rotating shaft. The fixed shaft accommodating portion  3281  may be disposed at a center of the fixed end plate  321 . 
     A thickness of the fixed end plate  321  may be equal to a thickness of the fixed shaft accommodating portion  3281 . In this regard, the fixed shaft accommodating portion  3281  may not protrude and extend from the fixed end plate  321 , but may be embedded in the fixed through-hole  328 . 
     The fixed side plate  322  may have a suction hole  325  defined therein for introducing the refrigerant into the fixed wrap  323 , and the fixed end plate  321  may have a discharge hole  326  defined therein for discharging the refrigerant. That is, the refrigerant may be introduced into the fixed wrap  323  via the suction port  111  and the suction hole  325 . The discharge hole  326  may be defined at a center of the fixed wrap  323 , but in order to avoid interference with the fixed shaft accommodating portion  3281 , the discharge hole  326  may be defined to be spaced apart from the fixed shaft accommodating portion  3281  and may include a plurality of discharge holes. 
     The orbiting scroll  330  may include an orbiting end plate  331  disposed between the main frame  310  and the fixed scroll  320 , and an orbiting wrap  333  forming the compression chamber together with the fixed wrap  323  on the orbiting end plate. 
     The orbiting scroll  330  may further include an orbiting through-hole  338  defined through the orbiting end plate  331  such that the rotating shaft  230  is rotatably coupled thereto. 
     The rotating shaft  230  may be constructed such that a portion thereof coupled to the orbiting through-hole  338  is eccentric. Accordingly, when the rotating shaft  230  rotates, the orbiting scroll  330  may move in engagement with the fixed wrap  323  of the fixed scroll  320  and may compress the refrigerant. 
     Specifically, the rotating shaft  230  may include a main shaft  231  coupled to the driver  200  and rotating, and a bearing portion  232  connected to the main shaft  231  and rotatably coupled to the compressing portion  300 . The bearing portion  232  may be formed as a member separate from the main shaft  231  and may accommodate the main shaft  231  therein, or may be formed integrally with the main shaft  231 . 
     The bearing portion  232  may include a main bearing portion  232   c  that is inserted into the main shaft accommodating portion  318  of the main frame  310  so as to be supported in a radial direction, a fixed bearing portion  232   a  that is inserted into the fixed shaft accommodating portion  3281  of the fixed scroll  320  so as to be supported in the radial direction, and an eccentric shaft  232   b  that is disposed between the main bearing portion  232   c  and the fixed bearing portion  232   a  and is inserted into the orbiting through-hole  338  of the orbiting scroll  330 . 
     In this regard, the main bearing portion  232   c  and the fixed bearing portion  232   a  may be formed coaxially to have the same axis center, and the eccentric shaft  232   b  may be formed such that a center of gravity thereof is radially eccentric with respect to the main bearing portion  232   c  or the fixed bearing portion  232   a . In addition, an outer diameter of the eccentric shaft  232   b  may be greater than an outer diameter of the main bearing portion  232   c  or an outer diameter of the fixed bearing portion  232   a . Accordingly, the eccentric shaft  232   b  may provide a force to compress the refrigerant while allowing the orbiting scroll  330  to orbit when the support shaft  232  rotates, and the orbiting scroll  330  may orbit the fixed scroll  320  regularly by the eccentric shaft  232   b.    
     In order to prevent the orbiting scroll  330  from rotating, the compressor  10  according to the present disclosure may further include an Oldham&#39;s ring  340  coupled to the orbiting scroll  330  from above. The Oldham&#39;s ring  340  may be disposed between the orbiting scroll  330  and the main frame  310  so as to be in contact with both the orbiting scroll  330  and the main frame  310 . The Oldham&#39;s ring  340  is constructed to move linearly in four directions of a forward direction, a rearward direction, a leftward direction, and a rightward direction so as to prevent the rotation of the orbiting scroll  330 . 
     In one example, the rotating shaft  230  may completely extend through the fixed scroll  320  and protrude outwardly of the compressing portion  300 . Accordingly, a region outside of the compressing portion  300 , the oil stored in the blocking shell  130 , and the rotating shaft  230  may be in direct contact with each other, and the rotating shaft  230  may supply the oil into the compressing portion  300  while rotating. 
     The oil may be supplied to the compressing portion  300  via the rotating shaft  230 . The oil supply passage  234  for supplying the oil to an outer circumferential surface of the main bearing portion  232   c , an outer circumferential surface of the fixed bearing portion  232   a , and an outer circumferential surface of the eccentric shaft  232   b  may be defined inside the rotating shaft  230 . 
     In addition, a plurality of oil holes  234   a, b, c , and  d  may be defined in the oil supply passage  234 . Specifically, the oil holes may include a first oil hole  234   a , a second oil hole  234   b , a third oil hole  234   c , and a fourth oil hole  234   d . First, the first oil hole  234   a  may be defined to extend through the outer circumferential surface of the main bearing portion  232   c.    
     In the oil supply passage  234 , the first oil hole  234   a  may be defined to extend through the outer circumferential surface of the main bearing portion  232   c . In addition, the first oil hole  234   a  may be defined, for example, to extend through an upper portion of the outer circumferential surface of the main bearing portion  232   c , but the present disclosure may not be limited thereto. That is, the first oil hole  234   a  may be defined to extend through a lower portion of the outer circumferential surface of the main bearing portion  232   c . For reference, the first oil hole  234   a  may include a plurality of holes, unlike the one illustrated in the drawing. In addition, when the first oil hole  234   a  include the plurality of holes, the hole may be defined only in the upper portion or the lower portion of the outer circumferential surface of the main bearing portion  232   c , or the holes may be defined in the upper portion and the lower portion of the outer circumferential surface of the main bearing portion  232   c , respectively. 
     In addition, the rotating shaft  230  may include an oil feeder  233  constructed to be in contact with the oil stored in the casing  100  through a muffler  500  to be described later. The oil feeder  233  may include an extension shaft  233   a  extending through the muffler  500  so as to be in contact with the oil, and a spiral groove  233   b  helically defined in an outer circumferential surface of the extension shaft  233   a  and in communication with the supply passage  234 . 
     Accordingly, when the rotating shaft  230  rotates, because of the spiral groove  233   b , a viscosity of the oil, and a pressure difference between a high-pressure region and an intermediate-pressure region inside the compressing portion  300 , the oil ascends via the oil feeder  233  and the supply passage  234 , and is discharged to the plurality of oil holes. The oil discharged via the plurality of oil holes  234   a ,  234   b ,  234   c , and  234   d  may form an oil film between the fixed scroll  250  and the orbiting scroll  240  so as to maintain an airtight state, and absorb a frictional heat generated in a portion where the components of the compressing portion  300  rub against each other so as to dissipate the heat. 
     The oil guided along the rotating shaft  230  and supplied via the first oil hole  234   a  may lubricate the main frame  310  and the rotating shaft  230 . In addition, the oil may be discharged via the second oil hole  234   b  and supplied to a top surface of the orbiting scroll  240 , and the oil supplied to the top surface of the orbiting scroll  240  may be guided to an intermediate-pressure chamber via a pocket groove  314 . For reference, the oil discharged through the first oil hole  234   a  or the third oil hole  234   d  as well as the second oil hole  234   b  may be supplied to the pocket groove  314 . 
     In one example, the oil guided along the rotating shaft  230  may be supplied to the Oldham&#39;s ring  340  and the fixed side plate  322  of and the fixed scroll  320  installed between the orbiting scroll  240  and the main frame  310 . Therefore, wear of the fixed side plate  322  of the fixed scroll  320  and the Oldham&#39;s ring  340  may be reduced. In addition, the oil supplied to the third oil hole  234   c  may be supplied to the compression chamber so as to not only reduce the wear caused by friction between the orbiting scroll  330  and the fixed scroll  320 , but also improve a compression efficiency by forming the oil film and dissipating the heat. 
     A centrifugal oil supply structure in which the lower scroll compressor  10  supplies the oil to the bearing portion using the rotation of the rotating shaft  230  has been described, but this is only one embodiment. In one example, a differential pressure oil supply structure that supplies the oil using the pressure difference inside the compressing portion  300  and a forced oil supply structure that supplies the oil via a trochoid pump or the like may be applied. 
     In one example, the compressed refrigerant is discharged to the discharge hole  326  along a space defined by the fixed wrap  323  and the orbiting wrap  333 . It may be more advantageous that the discharge hole  326  is defined to face the discharge port  121 . This is because it is most advantageous for the refrigerant discharged from the discharge hole  326  to be delivered to the discharge port  121  without a significant change in a flow direction. 
     However, because of the structural characteristics that the compressing portion  300  is disposed on the side of the driver  200  far from the discharge port  121  and the fixed scroll  320  is disposed at an outermost portion of the compressing portion  300 , the discharge hole  326  is defined to spray the refrigerant in a direction opposite to the discharge port  121 . 
     In other words, the discharge hole  326  is defined to spray the refrigerant in a direction away from the discharge port  121  from the fixed end plate  321 . Therefore, when the refrigerant is directly sprayed into the discharge hole  326 , the refrigerant may not be smoothly discharged to the discharge port  121 , and when the oil is stored in the blocking shell  130 , there may be a fear that the refrigerant collides with the oil to be cooled or mixed with the oil. 
     To prevent such problem, the compressor  10  according to the present disclosure may further include the muffler  500  coupled to the fixed scroll  320  to provide a space for guiding the refrigerant to the discharge port  121 . 
     The muffler  500  may be constructed to seal one surface of the fixed scroll  320  at a side far from the discharge port  121  so as to guide the refrigerant discharged from the fixed scroll  320  to the discharge port  121 . 
     The muffler  500  may include a coupled body  520  coupled to the fixed scroll  320  and an accommodating body  510  extending from the coupled body  520  so as to define a closed space. Accordingly, the refrigerant sprayed from the discharge hole  326  may be discharged to the discharge port  121  by changing the flow direction along the closed space defined by the muffler  500 . 
     In one example, because the fixed scroll  320  is coupled to the accommodating shell  110 , the refrigerant may be restricted from flowing to the discharge port  121  by being interrupted by the fixed scroll  320 . Accordingly, the fixed scroll  320  may further include a bypass hole  327  through which the refrigerant may pass through the fixed scroll  320  by passing through the fixed end plate  321 . The bypass hole  327  may be defined to be in communication with the main hole  317 . As a result, the refrigerant may pass through the compressing portion  300 , then pass through the driver  200 , and then be discharged through the discharge port  121 . 
     In one example, the refrigerant is compressed with a higher pressure inwardly from the outer circumferential surface of the fixed wrap  323 , so that regions inside the fixed wrap  323  and the orbiting wrap  333  maintain a high-pressure state. Therefore, the discharge pressure acts on a rear surface of the orbiting scroll as it is, and a back pressure acts from the orbiting scroll toward the fixed scroll as a reaction. The compressor  10  according to the present disclosure may further include a back pressure seal  350  that allows the back pressure to be concentrated in a portion where the orbiting scroll  330  and the rotating shaft  230  are coupled to each other so as to prevent leakage between the orbiting wrap  333  and the fixed wrap  323 . 
     The back pressure seal  350  may be formed in a ring shape so as to maintain an inner circumferential surface thereof at a high-pressure and separate an outer circumferential surface thereof at an intermediate-pressure lower than the high-pressure. Therefore, the back pressure is concentrated on the inner circumferential surface of the back pressure seal  350 , so that the orbiting scroll  330  is brought into close contact with the fixed scroll  320 . 
     In consideration of the discharge hole  326  being spaced apart from the rotating shaft  230 , the back pressure seal  350  may also be disposed such that a center thereof is biased toward the discharge hole  326 . In one example, the oil supplied to the compressing portion  300  or the oil stored in the casing  100  may flow to the upper portion of the casing  100  together with the refrigerant as the refrigerant is discharged through the discharge port  121 . In this regard, because the oil is denser than the refrigerant, the oil is not able to flow to the discharge port  121  by the centrifugal force generated by the rotor  220 , and is attached to the inner walls of the discharge shell  120  and the accommodating shell  110 . In the lower scroll compressor  10 , the driver  200  and the compressing portion  300  may further include recovery passages on outer circumferential surfaces thereof so as to recover the oil attached to the inner wall of the casing  100  to the oil storage space of the casing  100  or the blocking shell  130 , respectively. 
     The recovery passages may include a driver recovery passage  201  defined in the outer circumferential surface of the driver  200 , a compressing portion recovery passage  301  defined in the outer circumferential surface of the compressing portion  300 , and a muffler recovery passage  501  defined in the outer circumferential surface of the muffler  500 . 
     The driver recovery passage  201  may be defined as a portion of an outer circumferential surface of the stator  210  is recessed, and the compressing portion recovery passage  301  may be defined as a portion of the outer circumferential surface of the fixed scroll  320  is recessed. In addition, the muffler recovery passage  501  may be defined as a portion of the outer circumferential surface of the muffler is recessed. The driver recovery passage  201 , the compressing portion recovery passage  301 , and the muffler recovery passage  501  may be in communication with each other to allow the oil to pass therethrough. 
     As described above, because the center of gravity of the rotating shaft  230  is biased to one side because of the eccentric shaft  232   b , an unbalanced eccentric moment may occur during the rotation of the rotating shaft  230 , and thus overall balance may be disturbed. Accordingly, the lower scroll compressor  10  according to the present disclosure may further include a balancer  400  capable of offsetting an eccentric moment that may occur by the eccentric shaft  232   b.    
     Because the compressing portion  300  is fixed to the casing  100 , the balancer  400  is preferably coupled to the rotating shaft  230  itself or the rotor  220  constructed to rotate. Therefore, the balancer  400  may include a center balancer  410  disposed on a lower end of the rotor  220  or one surface of the rotor  220  facing the compressing portion  300  so as to offset or reduce an eccentric load of the eccentric shaft  232   b , and an outer balancer  420  coupled to an upper end of the rotor  220  or the other surface of the rotor  220  facing the discharge port  121  so as to offset an eccentric load or an eccentric moment of at least one of the eccentric shaft  232   b  and the lower balancer  420 . 
     Because the center balancer  410  is disposed relatively close to the eccentric shaft  232   b , the center balancer  410  may directly offset the eccentric load of the eccentric shaft  232   b . Therefore, it is preferable that the center balancer  410  is eccentric in a direction opposite to the eccentric shaft  232   b . As a result, even when the rotating shaft  230  rotates at a low speed or a high speed, because a spaced distance from the eccentric shaft  232   b  is small, the center balancer  410  may effectively offset the eccentric force or the eccentric load generated from the eccentric shaft  232   b  almost uniformly. 
     The outer balancer  420  may be eccentric in a direction opposite to the direction in which the eccentric shaft  232   b  is eccentric. However, the outer balancer  420  may be eccentric in a direction corresponding to the eccentric shaft  232   b  to partially offset the eccentric load generated by the center balancer  410 . 
     Accordingly, the center balancer  410  and the outer balancer  420  may offset the eccentric moment generated by the eccentric shaft  232   b  to assist the rotating shaft  230  to rotate stably. 
       FIG.  2    is a view showing that a portion of an oil passage is disposed outside and a main passage is constructed such that oil may be supplied to compressing portion, according to an embodiment of the present disclosure. 
     The compressor  10  according to the present embodiment may have a first passage  610  in communication with the oil supply passage  234  such that the oil may flow. 
     Specifically, the first passage  610  may be in communication with the oil supply passage  234  via the plurality of oil holes  234   a ,  234   b ,  234   d , and  234   e . In addition, the first passage  610  may be in communication with the oil supply passage  234  via a separate rotating shaft through-hole  235  extending through the rotating shaft  230  in addition to the plurality of oil holes  234   a ,  234   b ,  234   d , and  234   e . In addition, a plurality of rotating shaft through-holes  235  may be defined in the rotating shaft. 
     The first passage  610  in communication with the oil supply passage  234  may extend through the main end plate. That is, the oil flowing through the oil supply passage  234  may pass through the plurality of oil holes  234   a ,  234   b ,  234   d , and  234   e  and the rotating shaft through-hole  235  to flow into the first passage  610 . 
     The first passage  610  may be disposed perpendicular to a longitudinal direction of the rotating shaft. In addition, the first passage  610  may be inclined toward a side surface of the casing  100  with respect to the longitudinal direction of the rotating shaft. Based on a structural rigidity of the main frame  310  and a position of the rotating shaft through-hole  235 , a position and a shape of the first passage  610  may be freely selectable. 
     A second passage  620  may be constructed so as to extend from the first passage  610  and to allow the oil to flow to the outside of the casing  100 . 
     That is, the main end plate  311  may include the second passage  620  extending therethrough. The second passage  620  may be disposed in the main end plate  311  and may extend from the first passage  610 . 
     In addition, the second passage  620  may extend through the side surface of the casing  100 . The oil flowing through the first passage  610  may flow out of the casing  100  via the second passage  620 . 
     The second passage  620  may extend together with the first passage  610  by passing through the side surface of the casing  100  and the main end plate  311  in a straight line for convenience of manufacture and installation. 
     Accordingly, the first passage  610  and the second passage  620  may be disposed in the main end plate  311  and fixed in position while guiding the oil to the outside of the casing  100 . That is, the oil may flow stably and structural stability of the first passage  610  and the second passage  620  may be secured inside the compressor  10 , which is at high-temperature and high-pressure during operation. 
     The first passage  610  may mean a space defined inside the main end plate  311  and in which the oil flows. In addition, the first passage  610  may mean a pipe disposed inside the main end plate  311  and in communication with the rotating shaft through-hole  235 . However, the first passage  610  is not interpreted as being limited thereto. It is sufficient when the first passage  610  is in communication with the oil supply passage  234  to serve to guide the oil, and a shape of the first passage  610  is not limited. 
     The second passage  620  may mean a space defined through the side surfaces of the main end plate  311  and the casing  100 . That is, the second passage  620  may mean a space in which the oil that has passed through the first passage  610  flows. In addition, the second passage  620  may mean a pipe extending through the side surfaces of the main end plate and the casing  100 . However, the second passage  620  is not interpreted as being limited thereto. It is sufficient when the second passage  620  extends from the first passage  610  to serve to guide the oil to the outside of the casing, and a shape of the second passage  620  is not limited. 
     That is, the first passage  610 , which is the space defined through the main end plate  311  and in which the oil flows as described above, may be defined through the side surfaces of the main end plate  311  and the casing  100  and extend together with the second passage  620 , which is a space in which the oil flows. The oil may be guided to the outside of the casing  100  without a separate device such as a pipe. 
     In addition, the first passage  610  may mean the space defined inside the main end plate  311  and in which the oil flows, and the second passage  620  may mean the pipe extending through the side surfaces of the main end plate  311  and the casing  100  and in which the oil flows. 
     Conversely, the first passage  610  may mean a pipe disposed inside the main end plate  311 , extending through the main end plate  311 , and in which the oil flows, and the second passage  620 , as the space defined through the side surfaces of the main end plate  311  and the casing  100 , may mean a space in which the oil flows and a space in which the oil that has passed through the first passage  610  flows. 
     A third passage  630  extending from the second passage  620  and disposed outside the casing  100  may be disposed. 
     That is, the third passage  630  may be formed as a pipe such that the oil supplied from the oil supply passage  234  and passed through the first passage  610  and the second passage  620  flows outside the casing  100 . However, the third passage  630  is not interpreted as being limited thereto. It is sufficient when the third passage  630  extends from the second passage  620  such that the oil may flow outside the casing  100 , and a shape of the third passage  630  is not limited. 
     A main passage  640  extending from the third passage  630  and extending through the fixed scroll  320  or the main frame  310  may be disposed. 
     The main passage  640  may extend from the third passage  630  and may extend into the casing  100  through the side surface of the casing  100 . The main passage  640  may extend through a portion of the side surface of the casing  100  that is farther from the discharge port  121  than the second passage  620  is. This is for the convenience of installing the main passage  640  while supplying the oil to the space between the fixed scroll  320  and the orbiting scroll  330 . 
     The main passage  640  extending into the casing  100  may supply the oil to the compressing portion  300  through the fixed scroll  320  or the main frame  310 . 
     Specifically, a first inflow portion  641  may be disposed through one of the main side plate  312 , the fixed end plate  321 , and the fixed side plate  322 . The main passage  640  may be disposed in the first inflow portion  641 , so that the oil may be supplied to the space between the fixed scroll  320  and the orbiting scroll  330 . 
     In other words,  FIG.  2    shows that the first inflow portion  641  is disposed in the fixed end plate  321 , but the position where the first inflow portion  641  is disposed is freely selectable as long as the oil is able to be supplied to the space between the fixed scroll and the orbiting scroll. That is, the first inflow portion  641  may be disposed in the main side plate  312  or the fixed side plate  322 . 
     As the first inflow portion  641  is disposed in one of the fixed main side plate  312 , the fixed end plate  321 , and the fixed side plate  322 , the oil may be stably supplied to the space between the fixed scroll  320  and the orbiting scroll  330  via the main passage  640 . 
     As described above, from the oil supply passage  234 , the oil may be supplied from the inside of the casing  100  to the compressing portion  300  via the outside of the casing  100  through the first passage  610 , the second passage  620 , the third passage  630 , and the main passage  640 . 
     Accordingly, efficiency reduction caused by a phenomenon in which the oil is excessively supplied when an operating pressure is a high-pressure may be prevented. In addition, because the compressor may not include a pressure reducing pin and the like therein, an oil supply amount insufficiency may be prevented even when the operating pressure is a low-pressure, thereby enabling efficient oil supply. In addition, because the passage through which the oil flows is disposed outside of the casing  100 , repair and replacement may be easy when breakage or clogging of the passage occurs. 
       FIG.  3    is a view showing a first branch passage branched from a main passage according to an embodiment of the present disclosure, and  FIG.  4    is a view showing a second branch passage branched from a main passage according to an embodiment of the present disclosure. 
     Referring to  FIG.  3   , the compressor  10  according to the present embodiment may have a second inflow portion  651  in at least one of the main side plate  312 , the fixed end plate  321 , and the fixed side plate  322 . 
     The second inflow portion  651  may be disposed to extend through the fixed end plate  321 . The second inflow portion  651  may be located farther from the rotating shaft  230  than the first inflow portion  641 . 
     Although not shown in the drawing, the position of the second inflow portion  651  is freely selectable as long as the oil is able to be supplied to the space between the fixed scroll and the orbiting scroll. That is, the second inflow portion  651  may be located farther from the rotating shaft  230  than the first inflow portion  641  and may extend through the fixed side plate  322  or the main side plate  312 . 
     In addition, a first branched passage  650  may be constructed so as to be branched from the main passage  640  and to supply the oil via the second inflow portion  651 . That is, the oil may be supplied to the second inflow portion  651  having a lower pressure than the first inflow portion  641 . 
     Accordingly, the oil may be supplied to both sides via the main passage  640  and the first branched passage  650 , thereby securing variety of passages. In addition, even when the clogging phenomenon occurs in one of the main passage  640  and the first branched passage  650 , the oil may be smoothly supplied to the compressing portion  300 , thereby preventing the damage to the compressor  10 . 
     The first inflow portion  641  and the second inflow portion  651  may be disposed on the same side or on opposite sides with respect to the rotating shaft  230 . However, for convenience of installation of the main passage  640  and the first branched passage  650  and efficient utilization of space, preferably, the first inflow portion and the second inflow portion  651  are disposed on the opposite sides with respect to the rotating shaft  230 . 
     The first branched passage  650  may be branched from the main passage  640  from the outside of the casing  100 . This is to efficiently utilize the inner space of the casing  100 . 
     When the first branched passage  650  is branched from the main passage  640  from the outside of the casing  100 , the first branched passage  650  may extend through the side surface of the casing  100 . That is, the first branched passage  650  may be branched from the main passage  640  and extend into the casing  100  through the side surface of the casing  100 . 
     In addition, the first branched passage  650  may extend through a portion of the side surface of the casing  100  located farther from the discharge port  121  than the second passage  620 . This is for convenience of installation of the first branched passage  650  while supplying the oil to the space between the fixed scroll  320  and the orbiting scroll  330 . 
     This is only an example. When a sufficient space is secured inside the casing  100 , the first branched passage  650  may be branched from the main passage  640  inside the casing  100 . In this case, the first branched passage  650  may not extend through the side surface of the casing  100 . 
     Referring to  FIG.  4   , the compressor  10  according to the present embodiment may have a second branched passage  660  branched from the main passage  640 . That is, the second branched passage  660  may be constructed such that the oil flows to the suction port  111  located farther from the rotating shaft  230  than the first inflow portion  641 . 
     The first inflow portion  641  and the suction port  111  may be disposed on the same side or on opposite sides with respect to the rotating shaft  230 . However, for convenience of installation of the main passage  640  and the second branched passage  660  and efficient utilization of space, preferably, the first inflow portion  641  and the suction port  111  are disposed on the opposite sides with respect to the rotating shaft  230 . 
     The second branched passage  660  may be branched from the main passage  640  at a location outside of the casing  100 . In addition, the second branched passage  660  may extend through the suction port  111  such that the oil may flow to the suction port  111 . That is, the second branched passage  660  may extend directly to the suction port  111  at the location outside of the casing  100 . Accordingly, the second branched passage  660  may allow the oil to flow to be supplied to the suction port  111  from the outside of the casing  100 . 
     The oil that has passed through the third passage  630  may be supplied to the space between the fixed scroll  320  and the orbiting scroll  330  via the main passage  640 . In addition, the oil that has passed through the third passage  630  may be supplied to the suction port  111  via the second branched passage  660 . 
     Accordingly, the oil may be supplied to the both sides via the main passage  640  and the second branched passage  660 , thereby securing the variety of passages. In addition, even when the clogging phenomenon occurs in one of the main passage  640  and the second branched passage  660 , the oil may be smoothly supplied to the compressing portion  300 , thereby preventing the damage to the compressor  10 . In addition, the second branched passage may be located only outside the casing  100  without extending into the casing  100 , so that installation, repair, and replacement thereof may be easy. 
       FIG.  5    is a view showing passage adjusting portion disposed between the main passage and the first branched passage and constructed such that the passage is changeable, according to an embodiment of the present disclosure. 
     Hereinafter,  FIG.  5    will be described. A description of the content duplicate with the content described in  FIG.  3    will be omitted. However, not all of the same contents as those described above are omitted, and some may be described again for convenience of description and clear understanding of the invention. In addition, omissions should not be excluded or interpreted independently. 
     The compressor  10  according to the present embodiment may have passage adjusting portion  670  at a portion branching from the main passage  640  to the first branched passage  650 . 
     The passage adjusting portion  670  may be formed as a three-way valve. In addition, although not shown in the drawing, the passage adjusting portion  670  may include a main valve disposed on the main passage  640  and a branched valve disposed on the first branched passage  650 . The passage adjusting portion  670  may be appropriately selected in consideration of a space in which the compressor is installed, the operating pressure, an operating speed, an external environment, and the like. 
     When the passage adjusting portion  670  is formed as the three-way valve, the passage may be adjusted with one valve, so that installation may be easy and the installation space of the compressor  10  may be reduced. 
     The passage adjusting portion  670  may change the passage such that the oil flows into the main passage  640  or the first branched passage  650  based on the operating pressure. 
     That is, when the compressor  10  is operated at the high-pressure, the passage adjusting portion  670  may operate such that the oil may be supplied to the first inflow portion  641 . Conversely, when the compressor  10  is operated at the low-pressure, the passage adjusting portion  670  may operate such that the oil may be supplied to the second inflow portion  651 . 
     Specifically, the first inflow portion  641  is disposed closer to the rotating shaft than the second inflow portion  651 . Therefore, a pressure of the first inflow portion  641  is greater than a pressure of the second inflow portion  651 . 
     That is, when the compressor  10  is operated at the high-pressure, a difference between a pressure at which the oil is discharged from the oil supply passage  234  and the pressure of the second inflow portion  651  becomes greater than a pressure at which the oil may be efficiently supplied, so that the oil may be excessively supplied. Accordingly, it may cause a decrease in the efficiency of the compressor  10 . 
     Conversely, when the compressor  10  is operated at the low-pressure, a difference between a pressure of the portion of the oil supply passage  234  from which the oil is discharged and the pressure of the first inflow portion  641  becomes smaller than the pressure at which the oil may be efficiently supplied, so that the oil may be under-supplied. Accordingly, it may cause the decrease in the efficiency of the compressor  10 . 
     Accordingly, the passage adjusting portion  670  may be operated such that the oil is supplied to the main passage  640  or the first branched passage  650  based on the operating pressure, thereby improving the efficiency of the compressor  10 . 
     A reference value at which the passage adjusting portion  670  is adjusted such that the oil is supplied from the main passage  640  to the first branched passage  650  is as follows. 
     That is, the reference value may be a pressure ratio Pr defined by dividing a pressure Pd of the portion of the oil supply passage  234  from which the oil is discharged by a pressure Ps of the suction port  111 . Specifically, when the pressure ratio Pr is equal to or higher than 1.3, the passage adjusting portion  670  may be operated to allow the oil to flow to the main passage  640 . In addition, when the pressure ratio Pr is lower than 1.3, the passage adjusting portion  670  may be operated to allow the oil to flow to the first branched passage  650 . 
     The oil may be efficiently supplied to the space between the fixed scroll  320  and the orbiting scroll  330  by operating the passage adjusting portion  670  based on the reference value of the operating pressure. 
       FIG.  6    is a view showing passage adjusting portion disposed between a main passage and a second branched passage such that a passage is changeable, according to an embodiment of the present disclosure. 
     Hereinafter,  FIG.  6    will be described. A description of the content duplicate with the content described in  FIG.  4    will be omitted. However, not all of the same contents as those described above are omitted, and some may be described again for convenience of description and clear understanding of the invention. In addition, omissions should not be excluded or interpreted independently. 
     The compressor  10  according to the present embodiment may have the passage adjusting portion  670  at a portion branching from the main passage  640  to the second branched passage  660 . 
     The passage adjusting portion  670  may be formed as the three-way valve. In addition, although not shown in the drawing, the passage adjusting portion  670  may include the main valve disposed on the main passage  640  and a branched valve disposed on the second branched passage  660 . The passage adjusting portion  670  may be appropriately selected in consideration of the space in which the compressor is installed, the operating pressure, the operating speed, the external environment, and the like. 
     When the passage adjusting portion  670  is formed as the three-way valve, the passage may be adjusted with one valve, so that the installation may be easy and the installation space of the compressor  10  may be reduced. 
     The passage adjusting portion  670  may change the passage such that the oil flows into the main passage  640  or the second branched passage  660  based on the operating pressure. 
     That is, when the compressor  10  is operated at the high-pressure, the passage adjusting portion  670  may operate such that the oil may be supplied to the first inflow portion  641 . Conversely, when the compressor  10  is operated at the low-pressure, the passage adjusting portion  670  may operate such that the oil may be supplied to the suction port  111 . 
     Specifically, the first inflow portion  641  is disposed closer to the rotating shaft than the suction port  111 . Therefore, a pressure of the first inflow portion  641  is greater than a pressure of the suction port  111 . 
     That is, when the compressor  10  is operated at the high-pressure, a difference between the pressure at which the oil is discharged from the oil supply passage  234  and a pressure of the suction port  111  becomes greater than the pressure at which the oil may be efficiently supplied, so that the oil may be excessively supplied. Accordingly, it may cause the decrease in the efficiency of the compressor  10 . 
     Conversely, when the compressor  10  is operated at the low-pressure, a difference between the pressure of the portion of the oil supply passage  234  from which the oil is discharged and the pressure of the first inflow portion  641  becomes smaller than the pressure at which the oil may be efficiently supplied, so that the oil may be under-supplied. Accordingly, it may cause the decrease in the efficiency of the compressor  10 . 
     Accordingly, the passage adjusting portion  670  may be operated such that the oil is supplied to the main passage  640  or the second branched passage  660  based on the operating pressure, thereby improving the efficiency of the compressor  10 . 
     A reference value at which the passage adjusting portion  670  is adjusted such that the oil is supplied from the main passage  640  to the second branched passage  660  is as follows. 
     That is, the reference value may be the pressure ratio Pr defined by dividing the pressure Pd of the portion of the oil supply passage  234  from which the oil is discharged by the pressure Ps of the suction port  111 . Specifically, when the pressure ratio Pr is equal to or higher than 1.3, the passage adjusting portion  670  may be operated to allow the oil to flow to the main passage  640 . In addition, when the pressure ratio Pr is lower than 1.3, the passage adjusting portion  670  may be operated to allow the oil to flow to the first branched passage  650 . 
     The oil may be efficiently supplied to the space between the fixed scroll  320  and the orbiting scroll  330  by operating the passage adjusting portion  670  based on the reference value of the operating pressure. 
       FIG.  7    is a view showing a flow rate adjusting valve and a pressure sensor according to an embodiment of the present disclosure. 
     The compressor  10  according to the present embodiment may include a flow rate control valve  680  disposed on the third passage  630  or the main passage  640 . 
     When the flow rate control valve  680  is disposed on the main passage  640 , the flow rate control valve  680  may be installed outside the casing  100  for convenience of installation thereof and utilization of the inner space of the casing  100 . 
     An opening and closing rate of the flow rate adjusting valve  680  may be adjusted based on an amount of oil flowing into the third passage  630  or the main passage  640 . 
     Specifically, the flow rate adjusting valve  680  may be formed as an electric valve. The opening and closing rate may be electronically and automatically controlled based on the amount of oil flowing into the third passage  630  or the main passage  640 . 
     That is, when the amount of oil flowing through the third passage  630  or the main passage  640  is great, the opening and closing rate of the flow rate adjusting valve  680  may be reduced to reduce the amount of oil flowing through the third passage  630  or the main passage  640 . Conversely, when the amount of oil flowing through the third passage  630  or the main passage  640  is small, the opening and closing rate of the flow rate adjusting valve  680  may be increased to increase the amount of oil flowing through the third passage  630  or the main passage  640 . 
     In other words, an amount of supplied to the space between the fixed scroll  320  and the orbiting scroll  330  via the third passage  630  and the main passage  640  may be maintained constant. 
     Accordingly, the efficiency of the oil supply may be maintained high. Furthermore, the efficiency of the compressor  10  may be improved. In addition, an optimum amount of oil required for each condition based on the operating speed, the operating pressure, and the like may be supplied to the space between the fixed scroll  320  and the orbiting scroll  330 . 
     The compressor  10  according to the present embodiment may further include a pressure sensor  690  located rearwardly of the flow rate adjusting valve  680 . The pressure sensor  690  may be in communication with the third passage  630  or the main passage  640 . The pressure sensor  690  may measure the pressure of the third passage or the main passage  640 . The pressure sensor  690  may be installed outside the casing  100  for convenience of installation thereof. 
     The pressure measured by the pressure sensor  690  may be utilized by the flow rate adjusting valve  680  in measuring the amount of oil flowing to the third passage  630  or the main passage  640 . 
     In addition, the pressure measured by the pressure sensor  690  may identify the passage clogging phenomenon of the third passage  630  or the main passage  640 . Furthermore, the clogging phenomenon of the flow rate adjusting valve  680  may be identified. 
     When the passage clogging phenomenon is identified by the pressure sensor  690 , the flow rate adjusting valve  680  may be maximally opened to solve the passage clogging phenomenon. Accordingly, reliability of the oil supply of the compressor  10  may be secured. 
       FIG.  8    is a view showing a first branched passage, a flow rate adjusting valve, a pressure sensor, and passage adjusting portion according to an embodiment of the present disclosure. 
     Hereinafter,  FIG.  8    will be described. A description of the content duplicate with the content described in  FIGS.  3  and  5    will be omitted. However, not all of the same contents as those described above are omitted, and some may be described again for convenience of description and clear understanding of the invention. In addition, omissions should not be excluded or interpreted independently. 
     The compressor  10  according to the present embodiment may include the passage adjusting portion  670 , the flow rate adjusting valve  680 , and the pressure sensor  690 . 
     Specifically, the flow rate adjusting valve  680  and the pressure sensor  690  may be disposed forwardly of a portion branching from the main passage  640  to the first branched passage  650 . Accordingly, a pressure of an entire passage through which the oil flows may be measured and an oil flow rate of the entire passage through which the oil flows may be adjusted. 
     When the oil flows into the third passage  630  or the main passage  640  by the passage adjusting portion  670 , the opening and closing rate of the flow rate adjusting valve  680  may be adjusted based on the amount of oil flowing into the third passage  630  or the main passage  640 . 
     In addition, when the oil flows into the third passage  630  or the first branched passage  650  by the passage adjusting portion  670 , the opening and closing rate of the flow rate adjusting valve  680  may be adjusted based on the amount of oil flowing into the third passage  630  or the first branched passage  650 . 
     The pressure sensor  690  may be in communication with the third passage  630  or the main passage  640 . 
     When the oil flows into the third passage  630  or the main passage  640  by the passage adjusting portion  670 , the pressure sensor  690  may measure the pressure of the third passage  630  or the main passage  640 . 
     In addition, when the oil flows into the third passage  630  or the first branched passage  650  by the passage adjusting portion  670 , the pressure sensor  690  may measure the pressure of the third passage  630  or the first branched passage  650 . 
     When the oil flows to the main passage  640  via the third passage  630 , even when the clogging phenomenon occurs at a rear end of the main passage  640 , the oil may flow to the first branched passage  650  by the passage adjusting portion  670 , so that the oil may be continuously supplied. 
     In addition, when the oil flows to the first branched passage  650  via the third passage  630 , even when the clogging phenomenon occurs at a rear end of the first branched passage  650 , the oil may flow to the main passage  640  by the passage adjusting portion  670 , so that the oil may be continuously supplied. 
     Accordingly, even when the passage clogging phenomenon occurs, the passage clogging phenomenon may be solved by the passage adjustment of the passage adjusting portion  670 . Accordingly, the reliability of the oil supply of the compressor  10  may be secured. 
       FIG.  9    is a view showing a second branched passage, a flow rate adjusting valve, a pressure sensor, and a passage adjusting portion according to an embodiment of the present disclosure. 
     Hereinafter,  FIG.  9    will be described. A description of the content duplicate with the content described in  FIGS.  4  and  6    will be omitted. However, not all of the same contents as those described above are omitted, and some may be described again for convenience of description and clear understanding of the invention. In addition, omissions should not be excluded or interpreted independently. 
     The compressor  10  according to the present embodiment may include the passage adjusting portion  670 , the flow rate adjusting valve  680 , and the pressure sensor  690 . 
     The flow rate adjusting valve  680  and the pressure sensor  690  may be disposed forwardly of a portion branching from the main passage  640  to the second branched passage  660 . Accordingly, the pressure of the entire passage through which the oil flows may be measured and the oil flow rate of the entire passage through which the oil flows may be adjusted. 
     When the oil flows into the third passage  630  or the main passage  640  by the passage adjusting portion  670 , the opening and closing rate of the flow rate adjusting valve  680  may be adjusted based on the amount of oil flowing into the third passage  630  or the main passage  640 . 
     In addition, when the oil flows into the third passage  630  or the first branched passage  650  by the passage adjusting portion  670 , the opening and closing rate of the flow rate adjusting valve  680  may be adjusted based on the amount of oil flowing into the third passage  630  or the first branched passage  650 . 
     The pressure sensor  690  may be in communication with the third passage  630  or the main passage  640 . 
     When the oil flows into the third passage  630  or the main passage  640  by the passage adjusting portion  670 , the pressure sensor  690  may measure the pressure of the third passage  630  or the main passage  640 . 
     In addition, when the oil flows into the third passage  630  or the second branched passage  660  by the passage adjusting portion  670 , the pressure sensor  690  may measure the pressure of the third passage  630  or the second branched passage  660 . 
     When the oil flows to the main passage  640  via the third passage  630 , even when the clogging phenomenon occurs at the rear end of the main passage  640 , the oil may flow to the second branched passage  660  by the passage adjusting portion  670 , so that the oil may be continuously supplied. 
     In addition, when the oil flows to the second branched passage  660  via the third passage  630 , even when the clogging phenomenon occurs at a rear end of the second branched passage  660 , the oil may flow to the main passage  640  by the passage adjusting portion  670 , so that the oil may be continuously supplied. 
     Accordingly, even when the passage clogging phenomenon occurs, the passage clogging phenomenon may be solved by the passage adjustment of the passage adjusting portion  670 . Accordingly, the reliability of the oil supply of the compressor  10  may be secured. 
     Although representative embodiments of the present disclosure have been described in detail above, those with ordinary skill in the technical field to which the present disclosure belongs will understand that various modifications are possible with respect to the above-described embodiments without departing from the scope of the present disclosure. Therefore, the scope of rights of the present disclosure should not be limited to the described embodiments and should be defined by the claims to be described later as well as equivalents thereof.