SCROLL COMPRESSOR AND AIR CONDITIONER HAVING THE SAME

Abstract

A scroll compressor includes a casing, a drive motor, an orbiting scroll, a fixed scroll engaged with the orbiting scroll, a back pressure chamber proximate to the orbiting scroll, an inlet pipe for supplying refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, and a discharge pipe for discharging the refrigerant discharged from the compression chamber. The scroll compressor includes an oil feed passage configured to connect the back pressure chamber and an oil storage tank provided in the casing so that oil of the oil storage tank is supplied to the back pressure chamber; and a flow control valve disposed in the oil feed passage and configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage according to a suction pressure, a discharge pressure, and a rotational velocity.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Korean Patent Application No. 10-2014-0195251 filed Dec. 31, 2014 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] 1. Field

[0003] The present disclosure relates to a scroll compressor used in an air conditioner. More particularly, the present disclosure relates to a scroll compressor configured so that a predetermined back pressure is applied to the scroll compressor even when the scroll compressor is operated at a low load during variable operation, and to an air conditioner having the same.

[0004] 2. Description of the Related Art

[0005] A scroll compressor has high efficiency, low vibration, and low noise in comparison with other types of compressors, such as rotary compressors, etc., so scroll compressors have been used in various types of air conditioners. Recently, since the scroll compressor is required to operate in accordance with an actual load in order to save energy, the scroll compressor needs to operate at a high efficiency even when the load is small.

[0006] A back pressure in a back pressure chamber of the scroll compressor greatly influences the efficiency of the scroll compressor. The back pressure of the back pressure chamber is changed depending on operating conditions of the air conditioner. Accordingly, in the case in which the scroll compressor is designed so that back pressure capable of axial sealing is generated at a maximum load condition, then at a low load condition, the back pressure is lowered so that the axial sealing of the scroll compressor is not properly performed.

[0007] In the case in which the scroll compressor is designed so that a back pressure capable of the axial sealing is generated at a minimum load condition, then at the maximum load condition, more back pressure than necessary is generated so that the scroll compressor is overloaded.

SUMMARY

[0008] The present disclosure has been developed in order to overcome the above drawbacks and other problems associated with the conventional arrangement. An aspect of the present disclosure relates to a scroll compressor which can maintain constant back pressure in a back pressure chamber so as to maximize efficiency of the scroll compressor even when an operating condition of an air conditioner in which the scroll compressor is disposed is changed, and to an air conditioner having the same.

[0009] Another aspect of the present disclosure relates to a scroll compressor which can keep an amount of oil supplied to a compression chamber constant even when an operating condition of an air conditioner, in which the scroll compressor is disposed, is changed, and to an air conditioner having the same.

[0010] According to an aspect of the present disclosure, a scroll compressor may include a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber provided below the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, and a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing. The scroll compressor may include an oil feed passage configured to connect the back pressure chamber and an oil storage tank provided in a lower portion of the casing so that oil of the oil storage tank is supplied to the back pressure chamber; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational frequency or velocity of the drive motor.

[0011] The flow control valve may be configured to control an opening area of the oil feed passage.

[0012] The scroll compressor may be disposed in an outdoor unit of an air conditioner, and the flow control valve may be controlled by a controller of the air conditioner.

[0013] The scroll compressor may include a main frame configured to support the orbiting scroll and provided with the back pressure chamber, wherein the main frame is provided with an oil feed hole connected to a discharge end of the oil feed passage.

[0014] The oil feed hole may include a vertical hole which is connected to the back pressure chamber and is parallel to a drive shaft of the drive motor; and a horizontal hole which is formed perpendicular to the vertical hole and is connected to the discharge end of the oil feed passage.

[0015] When the drive motor is rotated at a low speed, the flow control valve may increase an amount of oil passing through the oil feed passage so that a back pressure of the back pressure chamber is a value between the suction pressure and the discharge pressure.

[0016] When the discharge pressure of the scroll compressor is maximum, the flow control valve may cut off the oil feed passage.

[0017] According to another aspect of the present disclosure, a scroll compressor may include a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber provided below the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing, and an oil separator that is connected to the discharge pipe, and separates and collects oil from the discharged refrigerant. The scroll compressor may include an oil feed passage configured to connect the oil separator and the back pressure chamber so that oil collected in the oil separator is supplied to the back pressure chamber; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational frequency or velocity of the drive motor.

[0018] The flow control valve may be configured to control an opening area of the oil feed passage.

[0019] The scroll compressor may be disposed in an outdoor unit of an air conditioner, and the flow control valve may be controlled by a controller of the air conditioner.

[0020] The scroll compressor may include a main frame configured to support the orbiting scroll and provided with the back pressure chamber, wherein the main frame is provided with an oil feed hole connected to a discharge end of the oil feed passage.

[0021] The oil feed hole may include a vertical hole which is connected to the back pressure chamber and is parallel to a drive shaft of the drive motor; and a horizontal hole which is formed perpendicular to the vertical hole and is connected to the discharge end of the oil feed passage.

[0022] When the drive motor is rotated at a low speed, the flow control valve may increase an amount of oil passing through the oil feed passage so that a back pressure of the back pressure chamber is a value between the suction pressure and the discharge pressure.

[0023] When the discharge pressure of the scroll compressor is maximum, the flow control valve may cut off the oil feed passage.

[0024] According to another aspect of the present disclosure, a scroll compressor may include a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber provided below the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, and a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing. The scroll compressor may include an oil feed passage configured to connect the compression chamber and an oil storage tank provided in a lower portion of the casing so that oil of the oil storage tank is supplied to the compression chamber; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the compression chamber via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational frequency or velocity of the drive motor.

[0025] The fixed scroll may include an auxiliary oil feed hole connecting the compression chamber and a discharge end of the oil feed passage.

[0026] The scroll compressor may be disposed in an outdoor unit of an air conditioner, and the flow control valve may be controlled by a controller of the air conditioner.

[0027] When the drive motor is rotated at a low speed, the flow control valve may increase an amount of oil passing through the oil feed passage.

[0028] According to another aspect of the present disclosure, a scroll compressor may include a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber provided below the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing, and a vapor refrigerant injection pipe. The scroll compressor may include an oil feed passage configured to connect an oil storage tank provided in a lower portion of the casing and the vapor refrigerant injection pipe so that oil in the oil storage tank is supplied to the compression chamber through the vapor refrigerant injection pipe; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the vapor refrigerant injection pipe via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational frequency or velocity of the drive motor.

[0029] According to another aspect of the present disclosure, an air conditioner may include an outdoor unit in which a scroll compressor having at least one of the above-described features is disposed; and a controller configured to control the scroll compressor in accordance with set conditions.

[0030] Other aspects, advantages and salient features of the present disclosure will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] These and/or other aspects and advantages of the present disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

[0032] FIG. 1 is a refrigerant circuit diagram illustrating a schematic configuration of an air conditioner having a scroll compressor according to an embodiment of the present disclosure;

[0033] FIG. 2 is a cross-sectional view illustrating a scroll compressor according to an embodiment of the present disclosure;

[0034] FIG. 3 is a partially enlarged cross-sectional view illustrating the scroll compressor of FIG. 2;

[0035] FIG. 4 is a cross-sectional view illustrating a scroll compressor according to another embodiment of the present disclosure;

[0036] FIG. 5 is a cross-sectional view illustrating a scroll compressor according to another embodiment of the present disclosure; and

[0037] FIG. 6 is a cross-sectional view illustrating a scroll compressor according to another embodiment of the present disclosure.

[0038] Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures.

DETAILED DESCRIPTION

[0039] Hereinafter, certain exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0040] The matters defined herein, such as a detailed construction and elements thereof, are provided to assist in a comprehensive understanding of this description. Thus, it is apparent that exemplary embodiments may be carried out without those defined matters. Also, well-known functions or constructions are omitted to provide a clear and concise description of exemplary embodiments. Further, dimensions of various elements in the accompanying drawings may be arbitrarily increased or decreased for assisting in a comprehensive understanding.

[0041] The terms used in the present application are only used to describe the exemplary embodiments, but are not intended to limit the scope of the disclosure. The singular expression also includes the plural meaning as long as it does not mean something different in the context. In the present application, the terms "include" and "consist of" designate the presence of features, numbers, steps, operations, components, elements, or a combination thereof that are written in the specification, but do not exclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, elements, or a combination thereof.

[0042] In the exemplary embodiment of the present disclosure, a "module" or a "unit" performs at least one function or operation, and may be implemented with hardware, software, or a combination of hardware and software. In addition, a plurality of "modules" or a plurality of "units" may be integrated into at least one module except for a "module" or a "unit" which has to be implemented with specific hardware, and may be implemented with at least one processor (not shown).

[0043] FIG. 1 is a refrigerant circuit diagram illustrating a schematic configuration of an air conditioner having a scroll compressor according to an embodiment of the present disclosure.

[0044] Referring to FIG. 1, an air conditioner 100 includes one outdoor unit 110, two indoor units 120, and a controller 130. However, the air conditioner 100 according to an embodiment of the present disclosure is not limited thereto. The number of the indoor units 120 that configures the air conditioner 100 as illustrated in FIG. 1 is only one example; therefore, the number of the indoor units 120 may be one or may be three or more.

[0045] The outdoor unit 110 and the indoor units 120 are connected to each other by pipes 121 and 122 through which refrigerant flows, thereby forming a refrigerant circuit. The two indoor units 120 are disposed in parallel in one example shown in FIG. 1.

[0046] The outdoor unit 110 is provided with a scroll compressor 1, a condenser 113, and an outdoor fan 115 to supply the condenser 113 with outdoor air. Accordingly, when operating the outdoor fan 115, the outdoor air is sucked into the outdoor unit 110, and then passes through the condenser 113.

[0047] The indoor unit 120 is provided with an expansion valve 124, an evaporator 123, and an indoor fan 125 for supplying the evaporator 123 with indoor air. Accordingly, when the indoor fan 125 is operated, the indoor air is sucked into the indoor unit 120, and then passes through the evaporator 123.

[0048] The controller 130 is electrically connected to the scroll compressor 1, the outdoor fan 115, and the indoor fan 125 so as to control the scroll compressor 1, the outdoor fan 115, and the indoor fan 125. The controller 130 operates the two indoor units 120 according to a user's operation. When both of the two indoor units 120 are operated, a maximum load is applied to the scroll compressor 1 of the outdoor unit 110. When one of the two indoor units 120 is operated, a minimum load is applied to the scroll compressor 1. If the air conditioner 100 includes three or more indoor units 120 such as system air conditioners, variation in the load being applied to the scroll compressor 1 is very large.

[0049] In the scroll compressor 1 according to an embodiment of the present disclosure, since constant back pressure is applied to the scroll compressor 1 even when the load varies, the sealing of a compression chamber may be effectively performed. Accordingly, since leakage of the refrigerant from the scroll compressor 1 is prevented, operating efficiency of the scroll compressor 1 may be improved.

[0050] Hereinafter, a scroll compressor 1 according to an embodiment of the present disclosure will be described in detail with reference to FIGS. 2 and 3.

[0051] FIG. 2 is a cross-sectional view illustrating a scroll compressor according to an embodiment of the present disclosure, and FIG. 3 is a partially enlarged cross-sectional view illustrating the scroll compressor of FIG. 2.

[0052] The scroll compressor 1 is configured to intake and compress refrigerant gas, and may include a casing 10, a main frame 20, a sub frame 30, a compression mechanism 40, a drive motor 70, an oil feed passage 80, and a flow control valve 90.

[0053] The casing 10 is formed in a cylindrical shape, and is a hermetically sealed container in an embodiment. The casing 10 accommodates the compression mechanism 40, the main frame 20, the sub frame 30, and the drive motor 70 in an inner space thereof. The main frame 20 and the sub frame 30 are fixed to an inside of the casing 10, and are spaced apart at a predetermined interval from each other in a vertical direction. The drive motor 70 is rotatably disposed between the main frame 20 and the sub frame 30.

[0054] Further, the casing 10 is provided with an inlet pipe 3 and a discharge pipe 5. The inlet pipe 3 passes through the casing 10, and one end of the inlet pipe 3 is connected to the compression mechanism 40. The discharge pipe 5 passes through the casing 10, and one end of the discharge pipe 5 is disposed in a space between the main frame 20 and the drive motor 70 in an inner space of the casing 10.

[0055] The compression mechanism 40 is disposed in an upper side of the main frame 20. An oil storage tank 35, in which oil or lubricant is stored, is provided below the sub frame 30.

[0056] The main frame 20 is formed in a substantially circular plate shape, and a projecting portion 21 is formed on a bottom surface of the main frame 20. The projecting portion 21 of the main frame 20 is provided with a shaft support hole 22. A bearing metal 23 is press-fitted in the shaft support hole 22. A main shaft portion 76 of a drive shaft 75 is inserted through the bearing metal 23, and the bearing metal 23 supports rotation of the drive shaft 75. A boss inserting groove 25 having an inner diameter that is larger than an inner diameter of the shaft support hole 22 is provided in the upper side of the shaft support hole 22.

[0057] An annular projection portion 26 forming a top end of the boss inserting groove 25 is provided on a top surface of the main frame 20. The upper surface of the annular projection portion 26 forms a mirror surface 26-1 that is in contact with and supports an orbiting scroll 60. Also, an oil ring 27 is disposed to surround the boss inserting groove 25 on the upper surface of the annular projection portion 26. An annular groove 28 is provided around the annular projection portion 26. The annular groove 28 forms a back pressure chamber. Oil supplied from the oil storage tank 35 fills the back pressure chamber 28. Also, an Oldham ring 69 for preventing rotation of the orbiting scroll 60 is disposed in the back pressure chamber 28 between the orbiting scroll 60 and the main frame 20. The oil ring 27 prevents the back pressure chamber 28 from being in fluid communication with the boss inserting groove 25.

[0058] An oil feed hole 24 in fluid communication with the back pressure chamber 28 which is provided to support the bottom surface of the orbiting scroll 60 in the top surface of the main frame 20 is formed in a side surface of the main frame 20. The oil feed hole 24 is connected to the oil feed passage 80 connected to the oil storage tank 35 provided in the lower portion of the casing 10. The oil feed hole 24 includes a vertical hole 24-1, which is connected to the back pressure chamber 28 and is parallel to a drive shaft 75 of the drive motor 70, and a horizontal hole 24-2, which is formed substantially perpendicular to the vertical hole 24-1 and is connected to a discharge end 81 of the oil feed passage 80.

[0059] The compression mechanism 40 includes a fixed scroll 50 and the orbiting scroll 60. The fixed scroll 50 is disposed above the main frame 20, and the orbiting scroll 60 is disposed in a space formed by the fixed scroll 50 and the main frame 20. The orbiting scroll 60 is engaged with the fixed scroll 50, is disposed between the fixed scroll 50 and the main frame 20, and orbits with respect to the fixed scroll 50.

[0060] The fixed scroll 50 includes a body portion 51 and a plurality of fixed scroll wraps 53. The body portion 51 is formed in a certain shape corresponding to the inner surface of the casing 10. Each of the plurality of fixed scroll wraps 53 is formed in an involute curved shape having predetermined thickness and height on one surface of the body portion 51. A discharge hole 55 is formed to pass through a center of the body portion 51. An inlet port 56 is formed at a side surface of the body portion 51. The inlet port 56 is connected to the inlet pipe 3 through which the refrigerant is introduced.

[0061] The orbiting scroll 60 includes a disc portion 61, a plurality of orbiting scroll wraps 63, and a boss portion 65. The disc portion 61 has certain thickness and area. Each of the plurality of orbiting scroll wraps 63 is formed in an involute curved shape having predetermined thickness and height on one surface of the disc portion 61. The plurality of orbiting scroll wraps 63 are formed to be engaged with the plurality of fixed scroll wraps 53. The boss portion 65 is formed at a center of the other side surface of the disc portion 61. The disc portion 61 is provided with first oil path 66 and second oil path 67 through which oil passes. The first oil path 66 is configured to connect the boss portion 65 and the top surface of the disc portion 61. The second oil path 67 is configured to connect the top surface of the disc portion 61 and the side surface of the disc portion 61.

[0062] The plurality of orbiting scroll wraps 63 of the orbiting scroll 60 are engaged with the plurality of fixed scroll wraps 53 of the fixed scroll 50, and the boss portion 65 is inserted in the boss inserting groove 25 of the main frame 20. Also, the one surface of the disc portion 61 on which the boss portion 65 is formed is supported by the mirror surface 26-1 of the main frame 20. Accordingly, the one surface of the disc portion 61 being supported by the mirror surface 26-1 of the main frame 20 also is formed as a mirror surface 61-1.

[0063] Compression pockets P formed by the plurality of fixed scroll wraps 53 of the fixed scroll 50 and the plurality of orbiting scroll wraps 63 of the orbiting scroll 60 configure a compression chamber.

[0064] The drive motor 70 includes a stator 71 and a rotor 72. The stator 71 is fixed to the inner surface of the casing 10. The rotor 72 is rotatably inserted inside the stator 71. Also, the drive shaft 75 is inserted through the rotor 72.

[0065] The drive shaft 75 includes a shaft portion 76 having a predetermined length and an eccentric portion 77 extending from one end of the shaft portion 76. The shaft portion 76 of the drive shaft 75 is press-fitted in the rotor 72 of the drive motor 70. The one end of the shaft portion 76 is inserted in the projecting portion 21 of the main frame 20 and is supported by the bearing metal 23. The eccentric portion 77 of the drive shaft 75 is inserted in the boss portion 65 of the orbiting scroll 60. A bearing metal 64 is disposed between the eccentric portion 77 of the drive shaft 75 and the boss portion 65 of the orbiting scroll 60.

[0066] A balance weight 74 is disposed in the shaft portion 76 of the drive shaft 75 above the rotor 72. The lower portion of the shaft portion 76 is supported by a bearing metal 31 disposed in the sub frame 30.

[0067] Also, the drive shaft 75 is provided with an oil-passage 78 formed to penetrate the shaft portion 76 and the eccentric portion 77. A bottom end 37 of the drive shaft 75 is submerged in the oil storage tank 35 of the casing 10. When the drive shaft 75 is rotated, oil stored in the oil storage tank 35 is supplied to the boss portion 65 of the orbiting scroll 60 via the oil passage 78 of the drive shaft 75 by pressure being applied to the oil storage tank 35.

[0068] The oil feed passage 80 is configured to connect the oil storage tank 35 provided in the lower portion of the casing 10 and the back pressure chamber 28 provided in the main frame 20. Accordingly, a discharge end 81 of the oil feed passage 80 is connected to the oil feed hole 24 formed in the main frame 20. The oil being received in the oil storage tank 35 is supplied to the back pressure chamber 28 via the oil feed passage 80 by the pressure being applied to the oil storage tank 35. The oil feed passage 80 may be formed of a pipe or a tube.

[0069] The flow control valve 90 is disposed in the oil feed passage 80, and adjusts an amount of the oil that passes through the oil feed passage 80 and moves to the back pressure chamber 28. The flow control valve 90 may be configured to adjust the amount of the oil passing through the oil feed passage 80 by controlling an opening area of the oil feed passage 80. The flow control valve 90 may use an electronic proportional solenoid valve that can adjust the opening area in accordance with electric signals. The flow control valve 90 may be configured to control the amount of the oil supplied via the oil feed passage 80 in accordance with a suction pressure of the refrigerant being sucked through the inlet pipe 3 of the casing 10, a discharge pressure of the refrigerant being discharged through the discharge pipe 5 of the casing 10, and a rotational frequency or velocity of the drive motor 70.

[0070] In the present embodiment in which the scroll compressor 1 is disposed in the air conditioner 100 (see FIG. 1), the flow control valve 90 is electrically connected to a controller 130 of the air conditioner 100 so that the flow control valve 90 is controlled by the controller 130. In detail, the controller 130 of the air conditioner 100 measures in real-time the suction pressure of the refrigerant being sucked through the inlet pipe 3 of the scroll compressor 1, the discharge pressure of the refrigerant being discharged through the discharge pipe 5 of the scroll compressor 1, and the rotational frequency or velocity of the drive motor 70, and controls the flow control valve 90 to supply an amount of oil that can apply a suitable pressure to the back pressure chamber 28 of the main frame 20 depending on the measured suction pressure, discharge pressure, and rotational frequency or velocity. Opening degrees of the flow control valve 90 depending on the suction pressure and discharge pressure of the refrigerant and the rotational frequency or velocity of the drive motor 70 may be stored in a memory of the controller 130 as a look-up table.

[0071] Hereinafter, operation of the scroll compressor 1 according to an embodiment of the present disclosure having the above-described structure will be described with reference to FIGS. 2 and 3.

[0072] First, when the power of the scroll compressor 1 is turned on, the power is applied to the drive motor 70 so that the rotor 72 of the drive motor 70 is rotated. When the rotor 72 of the drive motor 70 rotates, the drive shaft 75 integrally connected to the rotor 72 is rotated and supported by the bearing metal 23 of the main frame 20 and the bearing metal 31 of the sub frame 30. When the drive shaft 75 is rotated, the orbiting scroll 60 connected to the eccentric portion 77 of the drive shaft 75 orbits based on a shaft center of the drive shaft 75. At this time, the orbiting scroll 60 is prevented from rotating by an Oldham ring, and performs an orbiting motion.

[0073] When the orbiting scroll 60 is orbited by the drive shaft 75, the plurality of orbiting scroll wraps 63 of the orbiting scroll 60 are orbited while being engaged with the plurality of fixed scroll wraps 53 of the fixed scroll 50. Thus, the plurality of compression pockets P are formed by the plurality of orbiting scroll wraps 63 and the plurality of fixed scroll wraps 53. As the plurality of compression pockets P change in volume while moving toward the center of the fixed scroll 50 and the orbiting scroll 60, the compression pockets P suck refrigerant, compress the sucked refrigerant, and then discharge the compressed refrigerant through a discharge hole 55 of the fixed scroll 50. The refrigerant discharged through the discharge hole 55 enters the discharge pipe 5 disposed in a side wall of the casing 10 via the inner space of the casing 10, and is discharged outside the casing 10 through the discharge pipe 5. The refrigerant being introduced into the compression pockets P formed by the plurality of fixed scroll wraps 53 and orbiting scroll wraps 63 is sucked through the inlet port 56 that is formed in the side surface of the main frame 20 and is connected to the inlet pipe 3.

[0074] When the drive shaft 75 is rotated, the oil stored in the oil storage tank 35 of the lower portion of the casing 10 is supplied toward a top end of the drive shaft 75 through the oil passage 78 formed inside the drive shaft 75 the bottom end of which is submerged in the oil storage tank 35 by the pressure acting on the inside of the casing 10. The oil being supplied through the oil passage 78 formed in the drive shaft 75 fills the boss portion 65 of the orbiting scroll 60, and then fills the boss inserting groove 25 of the main frame 20 via the bearing metal 64 of the boss portion 65.

[0075] Some of the oil filling the boss portion 65 is supplied to the top surface of the orbiting scroll 60 via the first oil path 66 provided in the disc portion 61 of the orbiting scroll 60. The oil supplied to the top surface of the orbiting scroll 60 via the first oil path 66 is introduced between the plurality of fixed scroll wraps 53 of the fixed scroll 50 and the plurality of orbiting scroll wraps 63 of the orbiting scroll 60 so that the oil performs a sealing function to prevent leakage of the refrigerant as well as a lubrication function to prevent friction between the contact surfaces between the top end surfaces of the plurality of orbiting scroll wraps 63 and a contacting surface of the fixed scroll 50 in contact with the top end surfaces of the orbiting scroll wraps 63 and between the bottom end surfaces of the plurality of fixed scroll wraps 53 of the fixed scroll 50 and a contacting surface of the orbiting scroll 60 in contact with the bottom end surfaces of the plurality of fixed scroll 50.

[0076] Further, some of the oil supplied between the fixed scroll 50 and the orbiting scroll 60 is discharged through the side surface of the disc portion 61 of the orbiting scroll 60 via the second oil path 67, and then is supplied to the back pressure chamber 28. The oil supplied to the back pressure chamber 28 may press the orbiting scroll 60 upwardly so that the orbiting scroll 60 is orbited with respect to the fixed scroll 50 in a sealed state.

[0077] On the other hand, some of the oil filled in the boss inserting groove 25 is supplied between the mirror surface 61-1 of the disc portion 61 of the orbiting scroll 60 and the mirror surface 26-1 of the main frame 20. Also, some of the oil filled in the boss inserting groove 25 is returned to the oil storage tank 35 provided in the lower portion of the casing 10 via the bearing metal 23 disposed in the projecting portion 21 of the main frame 20.

[0078] Further, some of the oil supplied to the top end of the drive shaft 75 via the oil passage 78 of the drive shaft 75 is directly supplied to the bearing metal 23 disposed in the projecting portion 21 of the main frame 20 via an auxiliary oil passage 79 provided in the shaft portion 76 of the drive shaft 75.

[0079] When the scroll compressor 1 is disposed in the air conditioner 100 (see FIG. 1), the capacity of the scroll compressor 1 is varied in accordance with the load acting on the air conditioner 100. In other words, if the load becomes larger, the scroll compressor 1 increases the capacity for compressing the refrigerant by increasing the operation speed of the scroll compressor 1. When the load becomes smaller, the scroll compressor 1 decreases the capacity for compressing the refrigerant by reducing the operation speed of the scroll compressor 1.

[0080] When the operation speed of the scroll compressor 1 is taken at a high speed in order to increase the capacity of the scroll compressor 1, high-pressure is applied to the oil storage tank 35 so that a large amount of oil is supplied to the boss portion 65 via the oil passage 78 of the drive shaft 75. Therefore, the sufficient amount of oil is supplied between the plurality of orbiting scroll wraps 63 and the plurality of fixed scroll wraps 53 through the first oil path 66 of the disc portion 61 of the orbiting scroll 60, and the amount of oil being supplied to the back pressure chamber 28 via the first oil path 66 and the second oil path 67 becomes sufficient so that a proper back pressure is applied to the back pressure chamber 28, and thus the sealing of the compression chamber P is effectively performed. Accordingly, in this case, the flow control valve 90 blocks the oil, which is stored in the oil storage tank 35 of the casing 10, from being supplied to the back pressure chamber 28 via the oil feed passage 80 by cutting off the oil feed passage 80. For example, when the scroll compressor 1 rotates at a maximum speed, the flow control valve 90 may cut off the oil feed passage 80 so that the oil stored in the oil storage tank 35 of the casing 10 is not supplied to the back pressure chamber 28 via the oil feed passage 80.

[0081] However, when the operation speed of the scroll compressor 1 is at a low speed since the load of the air conditioner 100 (see FIG. 1) is small, low-pressure is applied to the oil storage tank 35 so that the amount of oil being supplied to the boss portion 65 of the orbiting scroll 60 via the oil passage 78 of the drive shaft 75 becomes small. Therefore, the amount of oil being supplied between the plurality of orbiting scroll wraps 63 and the plurality of fixed scroll wraps 53 through the first oil path 66 of the disc portion 61 of the orbiting scroll 60 is decreased, and in particular, the amount of oil being supplied to the back pressure chamber 28 via the first oil path 66 and the second oil path 67 is rapidly reduced.

[0082] As described above, when the amount of oil being supplied via the oil passage 78 of the drive shaft 75 is small due to the low operation speed of the scroll compressor 1, in the scroll compressor 1 according to an embodiment of the present disclosure, the oil accommodated in the oil storage tank 35 of the casing 10 is supplied to the back pressure chamber 28 of the main frame 20 via the oil feed passage 80. At this time, the flow control valve 90 controls properly the amount of oil passing through the oil feed passage 80 in accordance with the suction pressure of the refrigerant being sucked into the scroll compressor 1, the discharge pressure of the refrigerant being discharged from the scroll compressor 1, and the rotational frequency or velocity of the drive motor 70. Accordingly, in the scroll compressor 1 according to an embodiment of the present disclosure, even when the scroll compressor 1 is rotated at a low speed, the oil stored in the oil storage tank 35 of the casing 10 is supplied to the back pressure chamber 28 via the oil feed passage 80 disposed in the outside of the casing 10 as well as via the oil passage 78 of the drive shaft 75 so that a proper back pressure is generated in the back pressure chamber 28. In other words, the oil of the oil storage tank 35 may be supplied to the back pressure chamber 28 via the oil feed passage 80 so that the back pressure in the back pressure chamber 28 becomes a value between the suction pressure and the discharge pressure of the refrigerant.

[0083] For example, when a ratio of the discharge pressure Pd to the suction pressure Ps is 2 or less, namely, Pd/Ps.ltoreq.2, and the rotational frequency or velocity is 30 revolutions per second (RPS) or less, namely, RPS.ltoreq.30, the controller 130 may be set to open the flow control valve 90 so that the oil in the oil storage tank 35 is supplied to the back pressure chamber 28 through the oil feed passage 80.

[0084] Accordingly, in the scroll compressor 1 according to an embodiment of the present disclosure having the structure as described above, when the scroll compressor 1 is rotated at a high speed due to the high load of the scroll compressor 1 so that a high pressure is applied to the inside of the casing 10, the oil is sufficiently supplied to the back pressure chamber 28 via the oil passage 78 of the drive shaft 75 so that the compression chamber P formed by the fixed scroll 50 and the orbiting scroll 60 is effectively sealed. Also, when the scroll compressor 1 is rotated at a low speed due to the low load of the scroll compressor 1 so that a low pressure is applied to the inside of the casing 10, the oil of the oil storage tank 35 is directly supplied to the back pressure chamber 28 via the oil feed passage 80 disposed outside the casing 10 in addition to the oil passage 78 of the drive shaft 75 so that a proper back pressure is applied to the back pressure chamber 28. As a result, the compression chamber P formed by the fixed scroll 50 and the orbiting scroll 60 is effectively sealed. Accordingly, even if the size of the load acting on the air conditioner 100 varies, the scroll compressor 1 according to an embodiment of the present disclosure may be operated at a high efficiency.

[0085] Hereinafter, a scroll compressor according to another embodiment of the present disclosure will be described with reference to FIG. 4.

[0086] FIG. 4 is a cross-sectional view illustrating a scroll compressor according to another embodiment of the present disclosure.

[0087] Referring to FIG. 4, a scroll compressor 1' according to an embodiment of the present disclosure may include a casing 10, a main frame 20, a sub frame 30, a compression mechanism 40, a drive motor 70, an oil feed passage 80', and a flow control valve 90.

[0088] The casing 10, the main frame 20, the sub frame 30, the compression mechanism 40, and the drive motor 70 are the same as those of the scroll compressor 1 according to the above-described embodiment; therefore, detailed descriptions thereof will be omitted.

[0089] The scroll compressor 1' according to the present embodiment is different from the scroll compressor 1 according to the above-described embodiment in that oil separated by an oil separator 200 is supplied to the back pressure chamber 28 instead of oil of the oil storage tank 35 of the casing 10.

[0090] Accordingly, the oil separator 200 for separating oil from the refrigerant discharged from the scroll compressor 1' is disposed in one side of the scroll compressor 1' according to an embodiment of the present disclosure. An inlet 201 to which the discharge pipe 5 of the scroll compressor 1' is connected is provided in a side surface of the oil separator 200. A refrigerant discharge pipe 203 is connected to a top end of the oil separator 200, and an oil return pipe 205 is provided at a bottom end of the oil separator 200. The refrigerant containing oil is introduced into the oil separator 200 through the inlet 201, and the oil is separated from the refrigerant by the oil separator 200. The refrigerant from which the oil has been removed is supplied to the condenser 113 (see FIG. 1) through the refrigerant discharge pipe 203, and the separated oil is discharged through the oil return pipe 205.

[0091] The oil feed passage 80' is configured to connect the oil return pipe 205 of the oil separator 200 and the back pressure chamber 28 of the casing 10. Accordingly, the main frame 20 of the scroll compressor 1' is provided with an oil feed hole 24 which is connected to a discharge end 81 of the oil feed passage 80'. The oil feed hole 24 includes a vertical hole 24-1, which is connected to the back pressure chamber 28 and is parallel to the drive shaft 75 of the drive motor 70, and a horizontal hole 24-2, which is formed substantially perpendicular to the vertical hole 24-1 and is connected to the discharge end 81 of the oil feed passage 80'. Accordingly, the oil separated in the oil separator 200 may be supplied to the back pressure chamber 28 through the oil feed passage 80' connecting the oil separator 200 and the back pressure chamber 28 of the scroll compressor 1'. At this time, the oil separated in the oil separator 200 is supplied to the back pressure chamber 28 by the difference in pressure acting on the oil separator 200 and the back pressure chamber 28.

[0092] Also, the oil feed passage 80' is provided with a flow control valve 90 to control the amount of oil that passes through the oil feed passage 80' and moves to the back pressure chamber 28. The flow control valve 90 may be configured to adjust the amount of the oil passing through the oil feed passage 80' by controlling an opening area of the oil feed passage 80'. The flow control valve 90 may use an electronic proportional solenoid valve that can adjust the opening area in accordance with electric signals. The flow control valve 90 may be configured to control the amount of the oil supplied via the oil feed passage 80' in accordance with the suction pressure of the refrigerant being sucked through the inlet pipe 3 of the casing 10, the discharge pressure of the refrigerant being discharged through the discharge pipe 5 of the casing 10, and the rotational frequency or velocity of the drive motor 70. The flow control valve 90 is the same as the flow control valve 90 of the scroll compressor 1 according to the above-described embodiment; therefore, a detailed description thereof will be omitted.

[0093] In the scroll compressor 1' according to an embodiment of the present disclosure having the above-described structure, when the scroll compressor 1' is rotated at a high speed because a high load is applied to the air conditioner 100, the oil is sufficiently supplied to the compression chamber P formed by the fixed scroll 50 and the orbiting scroll 60 and the back pressure chamber 28 formed by the orbiting scroll 60 and the main frame 20 via the oil passage 78 of the drive shaft 75 in the same as the scroll compressor 1 according to the above-described embodiment. Accordingly, the scroll compressor 1' may efficiently compress and discharge the refrigerant being sucked. At this time, the flow control valve 90 blocks the oil collected by the oil separator 200 from being supplied to the back pressure chamber 28 by cutting off the oil feed passage 80'.

[0094] However, when the scroll compressor 1' is rotated at a low speed since a low load is applied to the air conditioner 100, the amount of oil being supplied to the compression chamber P formed by the fixed scroll 50 and the orbiting scroll 60 and the back pressure chamber 28 formed by the orbiting scroll 60 and the main frame 20 via the oil passage 78 of the drive shaft 75 is reduced. In this case, the flow control valve 90 properly controls the amount of oil being supplied to the back pressure chamber 28 in accordance with the load being applied to the scroll compressor 1'.

[0095] In detail, the flow control valve 90 properly controls the amount of the oil that passes through the oil feed passage 80' and is supplied to the back pressure chamber 28 in accordance with the suction pressure of the refrigerant being sucked into the scroll compressor 1', the discharge pressure of the refrigerant being discharged from the scroll compressor 1', and the rotational frequency or velocity of the drive motor 70. At this time, the flow control valve 90 may be controlled by the controller 130 of the air conditioner 100. Accordingly, in the scroll compressor 1' according to an embodiment of the present disclosure, even when the scroll compressor 1' is rotated at a low speed, the oil collected by the oil separator 200 is supplied to the back pressure chamber 28 via the oil feed passage 80' connected to the oil separator 200 that is disposed in the outside of the casing 10 as well as the oil passage 78 of the drive shaft 75 so that a proper pressure is generated in the back pressure chamber 28.

[0096] Accordingly, in the scroll compressor 1' according to an embodiment of the present disclosure having the structure as described above, when the scroll compressor 1' is rotated at a high speed due to the high load of the scroll compressor 1, the oil is sufficiently supplied to the back pressure chamber 28 via the oil passage 78 of the drive shaft 75 so that the compression chamber P formed by the fixed scroll 50 and the orbiting scroll 60 is effectively sealed. Also, when the scroll compressor 1' is rotated at a low speed since a low load acts on the scroll compressor 1', the oil separated in the oil separator 200 is directly supplied to the back pressure chamber 28 via the oil feed passage 80' disposed outside the casing 10 in addition to the oil passage 78 of the drive shaft 75 so that the compression chambers P formed by the fixed scroll 50 and the orbiting scroll 60 are effectively sealed. Accordingly, even if the size of the load acting on the air conditioner 100 varies, the scroll compressor 1' according to an embodiment of the present disclosure may be operated at a high efficiency.

[0097] Hereinafter, a scroll compressor according to another embodiment of the present disclosure will be described with reference to FIG. 5.

[0098] FIG. 5 is a cross-sectional view illustrating a scroll compressor according to another embodiment of the present disclosure.

[0099] Referring to FIG. 5, a scroll compressor 2 according to an embodiment of the present disclosure may include a casing 10, a main frame 20', a sub frame 30, a compression mechanism 40, a drive motor 70, an oil feed passage 80'', and a flow control valve 90.

[0100] The casing 10, the sub frame 30, the compression mechanism 40, and the drive motor 70 are the same as those of the scroll compressor 1 according to the above-described embodiment; therefore, detailed descriptions thereof will be omitted. However, the main frame 20' has a structure similar to that of the scroll compressor 1 as described above, but is different from the main frame 20 of the scroll compressor 1 according to the above described embodiment in that the main frame 20' is not provided with the oil feed hole 24.

[0101] The scroll compressor 2 according to the present embodiment is different from the scroll compressor 1 according to the above-described embodiment in the structure in which the oil of the oil storage tank 35 of the casing 10 is supplied to not the back pressure chamber 28 but the compression chamber P.

[0102] Accordingly, the scroll compressor 2 according to the present embodiment includes an oil feed passage 80'' that is provided in the outside of the casing 10 and connects the oil storage tank 35 of the casing 10 and the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60. An auxiliary oil feed hole 54 is formed in a side surface of the fixed scroll 50' in order to connect the oil feed passage 80'' and the compression chamber P. The auxiliary oil feed hole 54 is formed so that the side surface of the body portion 51 of the fixed scroll 50' is in fluid communication with the bottom surface of the body portion 51 on which the plurality of fixed scroll wraps 53 are not formed. In detail, the auxiliary oil feed hole 54 includes a horizontal hole 54-1 which is formed at the side surface of the body portion 51 and parallel to body portion 51 and a vertical hole 54-2 which is formed substantially perpendicular to the horizontal hole 54-1 and is formed to meet the horizontal hole 54-1 in a surface of the body portion 51 between the plurality of fixed scroll wraps 53. At this time, the vertical hole 54-2 may be disposed adjacent to the fixed scroll wrap 53 which is located outermost.

[0103] A discharge end 81 of the oil feed passage 80'' is connected to the horizontal hole 54-1 of the auxiliary oil feed hole 54. Accordingly, the oil stored in the oil storage tank 35 of the casing 10 may be supplied to the compression chamber P formed by the fixed scroll wraps 53 and the orbiting scroll wraps 63 through the oil feed passage 80'' and the auxiliary oil feed hole 54.

[0104] Also, a flow control valve 90 is provided in the oil feed passage 80'' to control the amount of oil that passes through the oil feed passage 80'' and is supplied to the compression chamber P. The flow control valve 90 may be configured to adjust the amount of the oil passing through the oil feed passage 80'' by controlling an opening area of the oil feed passage 80''. The flow control valve 90 may use an electronic proportional solenoid valve that can adjust the opening area in accordance with electric signals. The flow control valve 90 may be configured to control the amount of the oil supplied via the oil feed passage 80'' in accordance with the suction pressure of the refrigerant being sucked through the inlet pipe 3 of the casing 10, the discharge pressure of the refrigerant being discharged through the discharge pipe 5 of the casing 10, and the rotational frequency or velocity of the drive motor 70. The flow control valve 90 is the same as the flow control valve 90 of the scroll compressor 1 according to the above-described embodiment; therefore, a detailed description thereof will be omitted.

[0105] In the scroll compressor 2 according to an embodiment of the present disclosure having the above-described structure, when the scroll compressor 2 is rotated at a high speed because a high load is applied to the air conditioner 100, the oil is sufficiently supplied to the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60 via the oil passage 78 of the drive shaft 75 and the first oil path 66 of the orbiting scroll 60 in the same as the scroll compressor 1 according to the above-described embodiment. Also, some of the oil supplied to the compression chamber P may be supplied to the back pressure chamber 28 via the second oil path 67 provided in the orbiting scroll 60. Accordingly, the scroll compressor 2 may efficiently compress and discharge the refrigerant being sucked. At this time, the flow control valve 90 blocks the oil stored in the oil storage tank 35 of the casing 10 from being supplied to the compression chamber P by cutting off the oil feed passage 80''.

[0106] However, when the scroll compressor 2 is rotated at a low speed since a low load is applied to the air conditioner 100 (see FIG. 1), the amount of oil being supplied to the compression chamber P formed by the fixed scroll 50 and the orbiting scroll 60 via the oil passage 78 of the drive shaft 75 is reduced. In this case, the flow control valve 90 properly controls the amount of oil being supplied to the compression chamber P via the oil feed passage 80'' in accordance with the load being applied to the scroll compressor 2.

[0107] In detail, the flow control valve 90 properly controls the amount of the oil that passes through the oil feed passage 80'' and is supplied to the compression chamber P in accordance with the suction pressure of the refrigerant being sucked into the scroll compressor 2, the discharge pressure of the refrigerant being discharged from the scroll compressor 2, and the rotational frequency or velocity of the drive motor 70. At this time, the flow control valve 90 may be controlled by the controller 130 of the air conditioner 100. Accordingly, in the scroll compressor 2 according to an embodiment of the present disclosure, even when the scroll compressor 2 is rotated at a low speed, the oil of the oil storage tank 35 is supplied to the compression chamber P via the oil feed passage 80'' that is disposed in the outside of the casing 10 and is connected to the oil storage tank 35 as well as the oil passage 78 of the drive shaft 75 so that the compression chamber P is sufficiently sealed. Also, the oil is supplied to the back pressure chamber 28 through the second oil path 67 of the orbiting scroll 60 so that a proper back pressure is generated in the back pressure chamber 28.

[0108] Accordingly, in the scroll compressor 2 according to an embodiment of the present disclosure having the structure as described above, when the scroll compressor 2 is rotated at a high speed since the high load is applied to the scroll compressor 2, the oil is sufficiently supplied to the compression chamber P and the back pressure chamber 28 via the oil passage 78 of the drive shaft 75 so that the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60 is effectively sealed. Also, when the scroll compressor 2 is rotated at a low speed since a low load is applied to the scroll compressor 2, the oil of the oil storage tank 35 of the casing 10 is directly supplied to the compression chamber P via the oil feed passage 80'' disposed outside the casing 10 in addition to the oil passage 78 of the drive shaft 75 so that the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60 is effectively sealed. Accordingly, even if the size of the load acting on the air conditioner 100 varies, the scroll compressor 2 according to an embodiment of the present disclosure may be operated at a high efficiency.

[0109] Hereinafter, a scroll compressor according to another embodiment of the present disclosure will be described with reference to FIG. 6.

[0110] FIG. 6 is a cross-sectional view illustrating a scroll compressor according to another embodiment of the present disclosure.

[0111] Referring to FIG. 6, a scroll compressor 2' according to an embodiment of the present disclosure may include a casing 10, a main frame 20', a sub frame 30, a compression mechanism 40, a drive motor 70, an oil feed passage 80', and a flow control valve 90.

[0112] The casing 10, the main frame 20', the sub frame 30, the compression mechanism 40, and the drive motor 70 are the same as those of the scroll compressor 2 according to the above-described embodiment; therefore, detailed descriptions thereof will be omitted.

[0113] The scroll compressor 2' according to the present embodiment is different from the scroll compressor 2 according to the above-described embodiment in that it further includes a vapor refrigerant injection pipe 300 for supplying refrigerant to the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60.

[0114] Accordingly, a refrigerant injection hole 57 is provided in the one side surface of the fixed scroll 50'. The refrigerant injection hole 57 is formed so that the one side surface of the body portion 51 of the fixed scroll 50' is in fluid communication with a portion of the bottom surface of the body portion 51 on which the plurality of fixed scroll wraps 53 are not formed. In detail, the refrigerant injection hole 57 includes a horizontal hole 57-1 which is formed at the one side surface of the body portion 51 and parallel to body portion 51 and a vertical hole 57-2 which is formed substantially perpendicular to the horizontal hole 57-1 and is formed to meet the horizontal hole 57-1 in a portion of the bottom surface of the body portion 51 between the plurality of fixed scroll wraps 53. At this time, the vertical hole 57-2 may be disposed at a portion of the bottom surface of the body portion 51 adjacent to the fixed scroll wrap 53 which is located outermost. The vapor refrigerant injection pipe 300 is connected to the horizontal hole 57-1 of the refrigerant injection hole 57.

[0115] The oil feed passage 80''' of the scroll compressor 2' according to the present embodiment is disposed to connect the vapor refrigerant injection pipe 300 and the oil storage tank 35 of the casing 10 in the outside of the casing 10. A discharge end 81 of the oil feed passage 80''' is connected to the vapor refrigerant injection pipe 300. Accordingly, the oil stored in the oil storage tank 35 of the casing 10 is supplied to the vapor refrigerant injection pipe 300 through the oil feed passage 80''', and then is supplied to the compression chamber P formed by the fixed scroll 50 and the orbiting scroll 60 along with the refrigerant being introduced into the vapor refrigerant injection pipe 300.

[0116] Also, a flow control valve 90 is provided in the oil feed passage 80''' to control the amount of oil that passes through the oil feed passage 80' and is supplied to the vapor refrigerant injection pipe 300. The flow control valve 90 may be configured to adjust the amount of the oil passing through the oil feed passage 80''' by controlling an opening area of the oil feed passage 80'''. The flow control valve 90 may use an electronic proportional solenoid valve that can adjust the opening area in accordance with electric signals. The flow control valve 90 may be configured to control the amount of the oil supplied via the oil feed passage 80''' in accordance with the suction pressure of the refrigerant being sucked through the inlet pipe 3 of the casing 10, the discharge pressure of the refrigerant being discharged through the discharge pipe 5 of the casing 10, and the rotational frequency or velocity of the drive motor 70. The flow control valve 90 is the same as the flow control valve 90 of the scroll compressor 1 according to the above-described embodiment; therefore, a detailed description thereof will be omitted.

[0117] In the scroll compressor 2' according to an embodiment of the present disclosure having the above-described structure, when the scroll compressor 2' is rotated at a high speed because a high load is applied to the air conditioner 100, the oil is sufficiently supplied to the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60 via the oil passage 78 of the drive shaft 75 and the first oil path 66 of the orbiting scroll 60 in the same as the scroll compressor 1 according to the above-described embodiment. Also, some of the oil supplied to the compression chamber P may be supplied to the back pressure chamber 28 via the second oil path 67 provided in the orbiting scroll 60. Accordingly, the scroll compressor 2' may efficiently compress and discharge the refrigerant being sucked. At this time, the flow control valve 90 blocks the oil stored in the oil storage tank 35 of the casing 10 from being supplied to the compression chamber P via the vapor refrigerant injection pipe 300 by cutting off the oil feed passage 80'''. Accordingly, only vapor refrigerant is supplied to the compression chamber P through the vapor refrigerant injection pipe 300.

[0118] However, when the scroll compressor 2' is rotated at a low speed since a low load is applied to the air conditioner 100, the amount of oil being supplied to the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60 via the oil passage 78 of the drive shaft 75 is reduced. In this case, the flow control valve 90 properly controls the amount of oil being supplied to the vapor refrigerant injection pipe 300 via the oil feed passage 80''' in accordance with the load being applied to the scroll compressor 2'.

[0119] In detail, the flow control valve 90 properly controls the amount of the oil that passes through the oil feed passage 80''' and is supplied to the vapor refrigerant injection pipe 300 in accordance with the suction pressure of the refrigerant being sucked into the scroll compressor 2', the discharge pressure of the refrigerant being discharged from the scroll compressor 2, and the rotational frequency or velocity of the drive motor 70. At this time, the flow control valve 90 may be controlled by the controller 130 of the air conditioner 100. Accordingly, in the scroll compressor 2' according to an embodiment of the present disclosure, even when the scroll compressor 2' is rotated at a low speed, the oil of the oil storage tank 35 is supplied to the vapor refrigerant injection pipe 300 via the oil feed passage 80''', which is disposed in the outside of the casing 10 and is connected to the oil storage tank 35, and then is supplied to the compression chamber P together with the refrigerant through the vapor refrigerant injection pipe 300 as well as the oil passage 78 of the drive shaft 75 so that the compression chamber P is sufficiently sealed. Also, some of the oil in the compression chamber P is supplied to the back pressure chamber 28 through the second oil path 67 of the orbiting scroll 60 so that a proper back pressure is generated in the back pressure chamber 28.

[0120] Accordingly, in the scroll compressor 2' according to an embodiment of the present disclosure having the structure as described above, when the scroll compressor 2' is rotated at a high speed since a high load is applied to the scroll compressor 2', the oil is sufficiently supplied to the compression chamber P and the back pressure chamber 28 via the oil passage 78 of the drive shaft 75 so that the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60 is effectively sealed. Also, when the scroll compressor 2' is rotated at a low speed since a low load is applied to the scroll compressor 2', the oil of the oil storage tank 35 of the casing 10 is directly supplied to the compression chamber P with the refrigerant via the oil feed passage 80''' and the vapor refrigerant injection pipe 300 disposed outside the casing 10 in addition to the oil passage 78 of the drive shaft 75 so that the compression chamber P formed by the fixed scroll 50' and the orbiting scroll 60 is effectively sealed. Accordingly, even if the size of the load acting on the air conditioner 100 varies, the scroll compressor 2' according to an embodiment of the present disclosure may be operated at a high efficiency.

[0121] While the embodiments of the present disclosure have been described, additional variations and modifications of the embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims shall be construed to include both the above embodiments and all such variations and modifications that fall within the spirit and scope of the inventive concepts.

Claims

1. A scroll compressor which comprises a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber provided proximate to the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, and a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing, the scroll compressor comprising: an oil feed passage configured to connect the back pressure chamber and an oil storage tank provided in the casing so that oil of the oil storage tank is supplied to the back pressure chamber; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational velocity of the drive motor.

2. The scroll compressor of claim 1, wherein the flow control valve is configured to control an opening area of the oil feed passage.

3. The scroll compressor of claim 1, wherein the scroll compressor is disposed in an outdoor unit of an air conditioner, and the flow control valve is controlled by a controller of the air conditioner.

4. The scroll compressor of claim 1, further comprising: a main frame configured to support the orbiting scroll and provided with the back pressure chamber, wherein the main frame is provided with an oil feed hole connected to a discharge end of the oil feed passage.

5. The scroll compressor of claim 4, wherein the oil feed hole comprises: a vertical hole which is connected to the back pressure chamber and is parallel to a drive shaft of the drive motor; and a horizontal hole which is formed perpendicular to the vertical hole and is connected to the discharge end of the oil feed passage.

6. The scroll compressor of claim 1, wherein, when the drive motor is rotated at a low speed, the flow control valve increases an amount of oil passing through the oil feed passage so that a back pressure of the back pressure chamber is a value between the suction pressure and the discharge pressure.

7. The scroll compressor of claim 1, wherein, when the discharge pressure of the scroll compressor is maximum, the flow control valve cuts off the oil feed passage.

8. A scroll compressor which comprises a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber proximate to the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing, and an oil separator that is connected to the discharge pipe, and separates and collects oil from the discharged refrigerant, the scroll compressor comprising: an oil feed passage configured to connect the oil separator and the back pressure chamber so that oil collected in the oil separator is supplied to the back pressure chamber; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational velocity of the drive motor.

9. The scroll compressor of claim 8, wherein the flow control valve is configured to control an opening area of the oil feed passage.

10. The scroll compressor of claim 8, wherein the scroll compressor is disposed in an outdoor unit of an air conditioner, and the flow control valve is controlled by a controller of the air conditioner.

11. The scroll compressor of claim 8, further comprising: a main frame configured to support the orbiting scroll and provided with the back pressure chamber, wherein the main frame is provided with an oil feed hole connected to a discharge end of the oil feed passage.

12. The scroll compressor of claim 11, wherein the oil feed hole comprises: a vertical hole which is connected to the back pressure chamber and is parallel to a drive shaft of the drive motor; and a horizontal hole which is formed perpendicular to the vertical hole and is connected to the discharge end of the oil feed passage.

13. The scroll compressor of claim 8, wherein, when the drive motor is rotated at a low speed, the flow control valve increases an amount of oil passing through the oil feed passage so that a back pressure of the back pressure chamber is a value between the suction pressure and the discharge pressure.

14. The scroll compressor of claim 8, wherein, when the discharge pressure of the scroll compressor is maximum, the flow control valve cuts off the oil feed passage.

15. A scroll compressor which comprises a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber proximate to the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, and a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing, the scroll compressor comprising: an oil feed passage configured to connect the compression chamber and an oil storage tank provided in the casing so that oil of the oil storage tank is supplied to the compression chamber; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the compression chamber via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational velocity of the drive motor.

16. The scroll compressor of claim 15, wherein the fixed scroll comprises an auxiliary oil feed hole connecting the compression chamber and a discharge end of the oil feed passage.

17. The scroll compressor of claim 15, wherein the scroll compressor is disposed in an outdoor unit of an air conditioner, and the flow control valve is controlled by a controller of the air conditioner.

18. The scroll compressor of claim 15, wherein, when the drive motor is rotated at a low speed, the flow control valve increases an amount of oil passing through the oil feed passage.

19. A scroll compressor which comprises a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber proximate to the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing, and a vapor refrigerant injection pipe, the scroll compressor comprising: an oil feed passage configured to connect an oil storage tank provided in the casing and the vapor refrigerant injection pipe so that oil in the oil storage tank is supplied to the compression chamber through the vapor refrigerant injection pipe; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the vapor refrigerant injection pipe via the oil feed passage, wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational velocity of the drive motor.

20. An air conditioner comprising: an outdoor unit in which a scroll compressor is disposed; and a controller configured to control the scroll compressor in accordance with set conditions, wherein the scroll compressor comprises a casing, a drive motor accommodated in the casing, an orbiting scroll to be rotated by the drive motor, a fixed scroll engaged with the orbiting scroll, a back pressure chamber proximate to the orbiting scroll, an inlet pipe that is disposed in the casing and supplies refrigerant to a compression chamber formed by the orbiting scroll and the fixed scroll, and a discharge pipe that is disposed in the casing and discharges the refrigerant discharged from the compression chamber outside the casing, wherein the scroll compressor comprises, an oil feed passage configured to connect the back pressure chamber and an oil storage tank provided in the casing so that oil of the oil storage tank is supplied to the back pressure chamber; and a flow control valve disposed in the oil feed passage, the flow control valve configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage, and wherein the flow control valve controls the amount of oil to be supplied via the oil feed passage in accordance with a suction pressure of the refrigerant to be sucked through the inlet pipe, a discharge pressure of the refrigerant to be discharged through the discharge pipe, and a rotational velocity of the drive motor.

21. A scroll compressor, comprising: a fixed scroll of the scroll compressor engaged with an orbiting scroll; a back pressure chamber proximate to the orbiting scroll and connected to an oil source by an oil feed passage so that oil is supplied to the back pressure chamber; a flow control valve disposed in the oil feed passage and configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage in accordance with a suction pressure of refrigerant to be sucked through an inlet pipe, a discharge pressure of the refrigerant to be discharged through a discharge pipe, and a rotational velocity of a drive motor that rotates the orbiting scroll.

22. The scroll compressor of claim 21, wherein the flow control valve is configured to control the amount of oil to be supplied to the back pressure chamber.

23. The scroll compressor of claim 21, wherein the scroll compressor is disposed in an air conditioner, and the flow control valve is controlled by a controller of the air conditioner.

24. The scroll compressor of claim 21, wherein, the flow control valve maintains a back pressure of the back pressure chamber between the suction pressure and the discharge pressure when the drive motor is rotated at a low speed.

25. The scroll compressor of claim 21, wherein, the flow control valve cuts off the oil feed passage when the discharge pressure of the scroll compressor reaches a maximum.

26. The scroll compressor of claim 21, wherein the flow control valve is configured to supply oil to the back pressure chamber via the oil feed passage when a ratio of the discharge pressure to the suction pressure is 2 or less and the rotational velocity of the drive motor is 30 revolutions per second or less.

27. The scroll compressor of claim 21, wherein, the flow control valve comprises an electronic proportional solenoid valve.

28. An air conditioner having a scroll compressor, comprising: a fixed scroll of the scroll compressor engaged with an orbiting scroll; a back pressure chamber proximate to the orbiting scroll and connected to an oil source by an oil feed passage so that oil is supplied to the back pressure chamber; a flow control valve disposed in the oil feed passage and configured to control an amount of oil to be supplied to the back pressure chamber via the oil feed passage in accordance with a suction pressure of refrigerant to be sucked through an inlet pipe, a discharge pressure of the refrigerant to be discharged through a discharge pipe, and a rotational velocity of a drive motor that rotates the orbiting scroll.