Scroll compressor and air conditioner having the same

A scroll compressor according to the present disclosure and an air conditioner having the scroll compressor may include a drive motor provided in an inner space of a casing; a rotation shaft coupled to the drive motor; a frame provided on a lower side of the drive motor; a first scroll provided on a lower side of the frame, one side of which is formed with a first wrap; a second scroll in which a second wrap engaged with the first wrap is formed, and the rotation shaft is eccentrically coupled to the second wrap to overlap therewith in a radial direction, a compression chamber is formed between the first scroll and the second scroll while being orbitally moved with respect to the first scroll, and the compression chamber is connected to an evaporator outlet side of the cooling cycle; and an injection unit one end of which is branched from a refrigerant pipe between the condenser and the evaporator, and the other end of which is connected to the compression chamber through the first scroll.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure relates to subject matter contained in priority Korean Application No. 10-2017-0078851, filed on Jun. 22, 2017, which are herein expressly incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a scroll compressor and an air conditioner having the same, and more particularly, to a scroll compressor having a compression unit located at a lower side of an electric motor unit and an air conditioner having the same.

2. Description of the Related Art

An air conditioner is a home appliance for maintaining indoor air in a state suitable for its use and purpose. Such an air conditioner is driven by a cooling cycle for compressing, condensing, expanding and evaporating refrigerant, thereby performing a cooling or heating operation in an indoor space. Such an air conditioner may be divided into a separate air conditioner in which an indoor unit and an outdoor unit are separated from each other and an integrated air conditioner in which the indoor unit and the outdoor unit are combined into one unit depending on whether or not the indoor unit and the outdoor unit are separated from each other.

The outdoor unit includes an outdoor heat exchanger that performs heat exchange with outdoor air, and the indoor unit includes an indoor heat exchanger that performs heat exchange with indoor air. The air conditioner may be operated so as to be switchable to a cooling mode or a heating mode. When the air conditioner is operated in a cooling mode, the outdoor heat exchanger functions as a condenser and the indoor heat exchanger functions as an evaporator. On the contrary, when the air conditioner is operated in a heating mode, the outdoor heat exchanger functions as an evaporator and the indoor heat exchanger functions as a condenser.

Typically, when the outdoor air condition is poor, the cooling or heating performance of the air conditioner may be restricted. For example, a sufficient amount of circulation of refrigerant should be secured to obtain desired cooling and heating performance of the air conditioner when the outside temperature of a region in which the air conditioner is installed is very high or very low. For this purpose, when a compressor having a large capacity is provided, there is a problem in which the manufacturing and installation cost of the air conditioner is increased.

In view of this, a part of the refrigerant discharged from the compressor may be bypassed in the middle of the refrigeration cycle and injected into the middle of the compression chamber without increasing the capacity of the compressor. This is referred to as an injection cycle, and an air conditioner to which such an injection cycle is applied and a scroll compressor applied to the injection cycle type air conditioner are known.

As is known, a scroll compressor is a compressor that forms a compression chamber consisting of a suction chamber, an intermediate pressure chamber, and a discharge chamber between two scrolls when a plurality of scrolls perform a relative orbiting motion while being engaged with each other. The scroll compressor may obtain a stable torque due to suction, compression, and discharge strokes of the refrigerant being smoothly carried out while obtaining a relatively high compression ratio as compared with other types of compressors. Therefore, the scroll compressor is widely used for refrigerant compression in air conditioning devices or the like. In recent years, a high-efficiency scroll compressor having a reduced eccentric load at an operation speed above 180 Hz has been introduced.

A scroll compressor may be divided into a low-pressure type in which the suction pipe communicates with an inner space of the casing constituting a low-pressure portion, and a high-pressure type in which the suction pipe directly communicates with the compression chamber. Accordingly, the driving unit is provided in the suction space, which is a low-pressure portion, for the low-pressure type, while the driving unit is provided in the discharge space, which is a high-pressure portion, for the low-pressure type.

Such a scroll compressor may be divided into an upper compression type and a lower compression type according to the positions of the driving unit and the compression unit, and it is referred to as an upper compression type when the compression unit is located above the driving unit, and a lower compression type when the compression unit is located below the driving unit.

The scroll compressor receives a gas force in a direction that the orbiting scroll moves away from the fixed scroll (or including the non-orbiting scroll capable of moving up and down) while the pressure of the compression chamber usually rises. Then, as the orbiting scroll moves away from the fixed scroll, a leakage occurs between the compression chambers to increase compression loss.

In view of this, in a scroll compressor, a tip chamber method in which a sealing member is inserted into a front end surface of the fixed wrap and the orbiting wrap is applied, or a back pressure method in which a back pressure chamber making an intermediate pressure or discharge pressure is formed on a rear surface of the orbiting scroll or the fixed scroll to pressurize the orbiting scroll or the fixed scroll to the counterpart scroll by the pressure of the back pressure chamber.

As described above, there are prior arts related to a scroll compressor and an air conditioner applied to an injection cycle, such as Korean Patent Publication No. 10-2010-0096791 (Scroll compressor and cooling apparatus using the same) and Korean Patent No. 101382007 (Scroll compressor and air conditioner including the same) applied to an injection cycle.

However, all of these prior arts are applied to an upper compression scroll compressor, and there is a problem that the structure of the compressor itself is complicated, and oil feeding according to the operation speed of the compressor is not constant and the manufacturing cost is excessively high.

In addition, the upper compression scroll compressor has a structure in which the injected refrigerant is injected from an upper side to a lower side of the compression chamber, and thus there is a limitation in blocking liquid refrigerant from flowing into the compression chamber. In other words, the upper compression scroll compressor is provided with a main frame at a lower portion thereof, and a fixed scroll is provided at an upper side of the main frame, and an orbiting scroll is disposed between the main frame and the fixed scroll. Therefore, when an injection hole is formed in the main frame, the injection hole must pass through an end plate of the orbiting scroll, which may not be a practical structure. Accordingly, the injection hole is generally formed so as to pass through the fixed scroll forming an upper side of the compression chamber. However, when the injection hole is penetrated from an upper side of the compression chamber, gas refrigerant and liquid refrigerant are injected together into the compression chamber during the process of injecting the refrigerant into the compression chamber through the injection hole, thereby causing compression loss.

SUMMARY OF THE INVENTION

An object of the present disclosure is to provide a scroll compressor capable of simplifying the structure of the compressor to reduce the manufacturing cost of a cooling cycle to which the compressor is applied as well as the compressor, and an air conditioner having the same.

Furthermore, another object of the present disclosure is to provide a scroll compressor capable of enhancing lubrication performance irrespective of the operation speed of the compressor to enhance the performance of a cooling cycle to which the compressor is applied as well as the compressor, and an air conditioner having the same.

In addition, still another object of the present disclosure is to provide a scroll compressor capable of effectively suppressing liquid refrigerant from flowing into an intermediate pressure chamber of the compressor applied to an injection cycle, and an air conditioner having the same.

In order to accomplish the objectives of the present disclosure, there is provided a scroll compressor, including a casing an inner space of which is communicably coupled to a discharge pipe connected to a condenser inlet side of a cooling cycle device; a drive motor provided in an inner space of the casing; a rotation shaft coupled to the drive motor; a frame provided on a lower side of the drive motor; a first scroll provided on a lower side of the frame, one side of which is formed with a first wrap; a second scroll in which a second wrap engaged with the first wrap is formed, and the rotation shaft is eccentrically coupled to the second wrap to overlap therewith in a radial direction, a compression chamber is formed between the first scroll and the second scroll while being orbitally moved with respect to the first scroll, and the compression chamber is connected to an evaporator outlet side of the cooling cycle; and an injection unit one end of which is branched from a refrigerant pipe between the condenser and the evaporator, and the other end of which is connected to the compression chamber through the first scroll.

Here, the injection unit may include an injection pipe one end of which is branched from a refrigerant pipe between the condenser and the evaporator, and the other end of which is penetrated and coupled to the casing; and an injection passage connected to the other end of the injection pipe and communicated with the compression chamber through an inside of the first scroll.

Furthermore, the injection passage may include a first passage formed toward the center from an outer circumferential surface of the first scroll; and a second passage one end of which is connected to the first passage and the other end of which is communicated with the compression chamber.

Furthermore, a bypass hole for discharging refrigerant compressed in the compression chamber prior to the final compression chamber may be formed in the first scroll, and an outlet of the injection unit may be communicated with another compression chamber having a pressure lower than a compression chamber communicating with the bypass hole.

Furthermore, a back pressure chamber may be formed between the frame and the second scroll, and an oil feeding path communicating between the back pressure chamber and the compression chamber may be formed in the first scroll, and an outlet of the injection unit may be communicated with another compression chamber having a pressure lower than a compression chamber communicating with the oil feeding path.

Furthermore, an outlet of the injection unit may be communicated with a compression chamber formed in a compression chamber subsequent to the suction completion of refrigerant being sucked into the compression chamber.

Furthermore, the injection unit may include a plurality of injection units, and the plurality of injection units may be formed at different angles with respect to a rotation angle of the rotation axis.

Furthermore, the plurality of injection units may communicate with compression chambers having different pressures, respectively.

Furthermore, the plurality of injection units may include a first injection unit and a second injection unit, and the first injection unit may be communicated with a compression chamber prior to the suction completion of refrigerant being sucked into the compression chamber, and the second injection unit may be communicated with a compression chamber subsequent to the suction completion of refrigerant being sucked into the compression chamber.

In addition, in order to accomplish the objectives of the present disclosure, there is provided a scroll compressor, including a casing an inner space of which is communicably coupled to a discharge pipe connected to a condenser inlet side of a cooling cycle device; a drive motor provided in an inner space of the casing; a rotation shaft coupled to the drive motor; a frame provided on a lower side of the drive motor; a first scroll provided on a lower side of the frame, one side of which is formed with a first wrap; a second scroll in which a second wrap engaged with the first wrap is formed, and a compression chamber is formed between the first scroll and the second scroll while being orbitally moved with respect to the first scroll, and the compression chamber is connected to an evaporator outlet side of the cooling cycle; and an injection unit one end of which is branched from a refrigerant pipe between the condenser and the evaporator, and the other end of which is connected to the compression chamber through the first scroll.

Moreover, in order to accomplish the objectives of the present disclosure, there is provided an air conditioner, including a condensing unit; a first expansion unit connected to an outlet of the condensing unit; an injection heat exchange unit connected to an outlet of the first expansion unit; a second expansion unit connected to an outlet of the injection heat exchange unit; an evaporation unit connected to an outlet of the second expansion unit; and a compressor having a suction unit connected to an outlet of the evaporation unit, a discharge unit connected to an inlet of the condensing unit, and an injection unit connected to an outlet of the injection connection unit, wherein the compressor includes the foregoing scroll compressor.

Here, the air conditioner may further include a refrigerant switching unit configured to switch a flow direction of refrigerant between the discharge unit and the condensing unit of the compressor.

Furthermore, the injection heat exchange unit may include an injection expansion unit; and an internal heat exchange unit configured to exchange heat between refrigerant that has passed through the injection expansion unit and refrigerant that has passed through the first expansion unit.

Furthermore, the injection heat exchange unit may include a plurality of injection heat exchange units connected in series, and the plurality of injection heat exchange units may include the injection expansion unit and the internal heat exchange unit, respectively.

Furthermore, the plurality of injection heat exchange units may communicate with compression chambers having different pressures.

The scroll compressor according to the present disclosure may be configured such that the compression unit composed of two pairs of scrolls is located below the electric motor unit, thereby simplifying the structure of the compressor to reduce the manufacturing cost of a cooling cycle to which the compressor is applied as well as the compressor.

Furthermore, as the compression unit is located below the electric motor unit as described above, the present disclosure may enhance oil feeding performance irrespective of the operation speed of the compressor to enhance the performance of a cooling cycle to which the compressor is applied as well as the compressor

In addition, as an injection passage is formed in a scroll constituting a lower surface of the compression chamber even in the foregoing compression unit, liquid refrigerant may be effectively suppressed from flowing into the compression chamber, thereby enhancing an efficiency of the compressor and an efficiency of a cooling cycle having the same.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a scroll compressor according to the present disclosure and an air conditioner having the same will be described in detail with reference to an embodiment illustrated in the accompanying drawings. For reference, the scroll compressor according to the present disclosure is a lower compression scroll compressor in which a compression unit is positioned below an electric motor unit, and a rotary shaft is overlapped on the same plane as the orbiting wrap. This type of scroll compressor is known to be suitable for applications to cooling cycles under high temperature and high compression ratio conditions.

FIG. 1is a longitudinal cross-sectional view showing a lower compression scroll compressor according to the present disclosure, andFIG. 2is a transverse cross-sectional view showing a compression unit inFIG. 1, andFIG. 3is a front view showing a part of a rotation shaft for explaining a sliding portion inFIG. 1, andFIG. 4is a longitudinal cross-sectional view for explaining an oil feeding path and an injection passage between the back pressure chamber and the compression chamber inFIG. 1.

Referring toFIG. 1, the lower compression scroll compressor1according to the present embodiment may be provided with an electric motor unit20formed with a drive motor inside a casing10to generate a rotational force, and provided with a compression unit30disposed at a predetermined space (hereinafter, intermediate space) below the electric motor unit20to receive the rotational force of the electric motor unit20so as to compress refrigerant.

The casing10includes a cylindrical shell11constituting a sealed container, an upper shell12covering an upper portion of the cylindrical shell11to constitute a sealed container together therewith, and a lower shell13covering a lower portion of the cylindrical shell11to form a storage space10cwhile constituting a sealed container together therewith.

A refrigerant suction pipe15may pass through a side surface of the cylindrical shell11to directly communicate with a suction chamber of the compression unit30, and a refrigerant discharge pipe16communicating with an upper space10bof the casing10may be provided at an upper portion of the upper shell12. The refrigerant discharge pipe16corresponds to a passage through which compressed refrigerant discharged to an upper space10bof the casing10from the compression unit30is discharged to the outside, and the refrigerant discharge pipe16may be inserted to the middle of the upper space10bof the casing10so that the upper space10bcan form a type of oil separation space. Furthermore, according to circumstances, an oil separator (not shown) for separating oil mixed into refrigerant may be connected to the refrigerant suction pipe15inside the casing10including the upper space10bor within the upper space10b.

The electric motor unit20includes a stator21and a rotor22which rotates inside the stator21. The stator21is formed with teeth and slots constituting a plurality of coil winding portions (not shown) on an inner circumferential surface of the stator21in a circumferential direction to wind a coil25, and a gap between an inner circumferential surface of the stator21and an outer circumferential surface of the rotor22is combined with the coil winding portion to form a second refrigerant passage (PG2). As a result, refrigerant discharged to the intermediate space10cbetween the electric motor unit20and the compression unit30through a first refrigerant passage (PG1) which will be described later flows into the upper space10bformed above the electric motor unit20through the second refrigerant passage (PG2) formed in the electric motor unit20.

Moreover, a plurality of D-cut faces21amay be formed on an outer circumferential surface of the stator21along an circumferential direction, and a first oil passage (PO1) may be formed between the D-cut faces21aand an inner circumferential surface of the cylindrical shell11to allow oil to pass therethrough. As a result, oil separated from refrigerant in the upper space10bmoves to the lower space10cthrough the first oil passage (PO1) and the second oil passage (PO2) which will be described later.

A frame31constituting the compression unit30may be fixedly coupled to an inner circumferential surface of the casing10at a predetermined distance below the stator21. An outer circumferential surface of the frame31may be shrink-fitted or welded and fixedly coupled to an inner circumferential surface of the cylindrical shell11.

Besides, an annular frame sidewall portion (first sidewall portion)311is formed at an edge of the frame31, and a plurality of communication grooves311bare formed along a circumferential direction on an outer circumferential surface of the first sidewall portion311. The communication grooves311btogether with the communication grooves322bof the first scroll32which will be described later form the second oil passage (PO2).

Furthermore, a first shaft receiving portion312for supporting a main bearing portion51of a rotation shaft50which will be described later may be formed at the center of the frame31, and a first shaft receiving hole312amay be formed in an axial direction in the first shaft receiving portion to pass therethrough such that the main bearing portion51of the rotation shaft50is rotatably inserted and supported in a radial direction.

In addition, a fixed scroll (hereinafter, referred to as a first scroll)32may be provided on a lower surface of the frame31with an orbiting scroll (hereinafter, referred to as a second scroll33) eccentrically coupled to the rotation shaft50interposed therebetween. The first scroll32may be fixedly coupled to the frame31, but may also be movable coupled thereto in an axial direction.

On the other hand, for the first scroll32, a fixed end plate portion (hereinafter, referred to as a first end plate portion)321may be formed in a substantially disk shape, and a scroll sidewall portion (hereinafter, referred to as a second sidewall portion)322coupled to a lower end of the frame31may be formed at an edge of the first end plate portion321.

A suction port324through which the refrigerant suction pipe15communicates with the suction chamber may be formed in a penetrating manner at one side of the second sidewall portion322, and a discharge port325communicated with the discharge chamber to discharge compressed refrigerant may be formed at the center of the first end plate portion321. Only one discharge port325may be formed to communicate with both a first compression chamber (V1) and a second compression chamber (V2) which will be described later, but a first discharge port325aand a second discharge port325bmay be formed to communicate independently the first compression chamber (V1) and the second compression chamber (V2).

Furthermore, the communication groove322bdescribed above is formed on an outer circumferential surface of the second sidewall portion322, and the communication groove322bforms the second oil passage (PO2) for guiding oil collected together with the communication groove311bof the first sidewall portion311to the lower space10c.

In addition, a discharge cover34for guiding refrigerant discharged from the compression chamber (V) to a refrigerant passage which will be described later may be coupled to a lower side of the first scroll32. An inner space of the discharge cover34may be formed to receive the discharge ports325a,325bwhile receiving an inlet of the first refrigerant passage (PG1) for guiding refrigerant discharged from the compression chamber (V) through the discharge ports325a,325bto the upper space10bof the casing10, more precisely, to a space between the electric motor unit20and the compression unit30.

Here, the first refrigerant passage (PG1) may be formed by sequentially passing through the second sidewall portion322of the fixed scroll32and the first sidewall portion311of the frame31from an inner side of the passage separation unit40, that is, a side of the rotation shaft50on an inner side with respect to the passage separation unit40. As a result, the second oil passage (PO2) described above is formed outside the passage separation unit40so as to communicate with the first oil passage (PO1).

Furthermore, a fixed wrap (hereinafter, referred to as a first wrap)323engaged with an orbiting wrap (hereinafter, referred to as a second wrap)332to form a compression chamber (V) may be formed on an upper surface of the first end plate portion321. The first wrap323will be described later with the second wrap332.

In addition, a second shaft receiving portion326for supporting a sub-bearing portion52of the rotation shaft50which will be described later may be formed at the center of the first end plate portion321, and the second bearing portion326may be formed with a second shaft receiving hole326apassing therethrough in an axial direction to support the sub-bearing portion52in a radial direction.

Moreover, a bypass hole381for bypassing part of refrigerant to be compressed in advance is formed in the first end plate portion321, and a bypass valve385is provided at the outlet end of the bypass hole381. At least one or more bypass holes381may be formed at appropriate positions along the advancing direction of the compression chamber (V) to be positioned between the suction chamber and the discharge chamber. Besides, an interval between the bypass holes381may be formed to be smaller toward the discharge side in the compression chamber (V2) having a large compression gradient.

On the other hand, for the second scroll33, an orbiting plate portion (hereinafter, referred to as a second plate portion)331may be formed in a substantially circular plate shape. A second wrap332engaged with the first wrap322to form a compression chamber may be formed on a lower surface of the second end plate331.

The second wrap332may be formed in an involute shape together with the first wrap323, but may be formed in various other shapes. For example, as shown inFIG. 2, the second wrap332may have a shape in which a plurality of arcs having different diameters and origin points are connected to each other, and an outermost curve may be formed in a substantially elliptical shape having a major axis and a minor axis. The first wrap323may be formed in the same manner.

A rotation axis coupling portion333which forms an inner end portion of the second wrap332and to which an eccentric portion53of the rotation shaft50which will be described later is rotatably inserted and coupled may be formed in an axially penetrating manner at a central portion of the second end plate portion331.

An outer circumferential portion of the rotation shaft coupling portion333is connected to the second wrap332to form the compression chamber (V) together with the first wrap322during the compression process.

Furthermore, the rotation shaft coupling portion333may be formed to have a height that overlaps with the second wraps332on the same plane, and disposed at a height where the eccentric portion53of the rotation axis50overlaps with the second wraps332on the same plane. Through this, the repulsive force and the compressive force of the refrigerant are canceled each other while being applied to the same plane with respect to the second end plate portion, thereby preventing an inclination of the second scroll33due to an action of the compressive force and the repulsive force.

Furthermore, the rotation shaft coupling portion333is formed with a concave portion335to be engaged with a protrusion portion328of the first wrap323which will be described later in an outer circumferential portion opposed to an inner end portion of the first wrap323. One side of this concave portion335is formed with an increasing portion335afor increasing a thickness from an inner circumferential portion to an outer circumferential portion of the rotation shaft coupling portion333on an upstream side along the direction of forming the compression chamber (V). It may increase a compression path of the first compression chamber (V1) immediately before discharge, thereby increasing a compression ratio of the first compression chamber (V1) to be close to that of the second compression chamber (V2) as a result. The first compression chamber (V1) is a compression chamber formed between an inner surface of the first wrap323and an outer surface of the second wrap332, which will be described later, separately from the second compression chamber (V2).

The other side of the concave portion335is formed with an arc compression surface335bhaving an arc shape. A diameter of the arc compression surface335bis determined by a thickness of an inner end portion of the first wrap323(i.e., a thickness of the discharge end) and an orbiting radius of the second wrap332, and thus the diameter of the arc compression surface335bincreases when increasing the thickness of the inner end portion of the first wrap323. As a result, the thickness of the second wrap around the arc compression surface335bmay also increase to secure durability, and a compression path may be lengthened to increase a compression ratio of the second compression chamber (V2) accordingly.

Furthermore, a protrusion portion328protruded toward an outer circumferential portion of the rotation shaft coupling portion333may be formed adjacent to an inner end portion (suction end or start end) of the first wrap323corresponding to the rotation shaft coupling portion333, and a contact portion328aprotruded from the protrusion portion and engaged with the concave portion335may be formed on the protrusion portion328. In other words, the inner end portion of the first wrap323may be formed to have a larger thickness than the other portions. Therefore, a wrap strength of the inner end portion that receives the greatest compressive force on the first wrap323is improved to improve durability.

On the other hand, the compression chamber (V) may be formed between the first end plate portion321and the first wrap323, and between the second wrap332and the second end plate portion331, and a suction chamber, an intermediate pressure chamber, and a discharge chamber may be consecutively formed according to an advancing direction of the wrap.

As shown inFIG. 2, the compression chamber (V) includes a first compression chamber (V1) formed between an inner surface of the first wrap323and an outer surface of the second wrap332, and a second compression chamber (V2) formed between an outer surface of the first wrap323and an inner surface of the second wrap332.

In other words, the first compression chamber (V1) includes a compression chamber formed between two contact points (P11, P12) formed by the inner surface of the first wrap323and the outer surface of the second wrap332being in contact with each other, and the second compression chamber (V2) includes a compression chamber formed between two contact points (P21, P22) formed by the outer surface of the first wrap323and the inner surface of the second wrap332being in contact with each other.

Here, when an angle having a large value between angles formed by two lines connecting the center of the eccentric portion, that is, the center (O) of the rotation shaft coupling portion, and the two contact points (P11, P12) is α, the first compression chamber (V1) immediately before discharge has α<360° immediately before at least the start of discharge, and a distance (I) between normal vectors at the two contact points (P11, P12) also has a value larger than zero.

Due to this, the first compression chamber immediately before discharge may have a smaller volume than the case where the first compression chamber has the fixed wrap and the orbiting wrap made of an involute curve, and thus it may be possible to improve both a compression ratio of the first compression chamber (V1) and a compression ratio of the second compression chamber (V2).

On the other hand, as described above, the second scroll33may be orbitably installed between the frame31and the fixed scroll32. Furthermore, an oldham ring35for preventing the rotation of the second scroll33may be provided between an upper surface of the second scroll33and a lower surface of the frame31corresponding thereto, and a sealing member36forming a back pressure chamber (S1) which will be described later may be provided on an inner side of the oldham ring35.

Furthermore, an intermediate pressure space is formed by the oil feeding hole321aprovided in the second scroll32on an outer side of the sealing member36. The intermediate pressure space communicates with the intermediate pressure chamber (V) to function as a back pressure chamber as the intermediate pressure refrigerant is filled. Therefore, the back pressure chamber formed on the inner side around the sealing member36may be referred to as a first back pressure chamber (S1), and the intermediate pressure space formed on the outside may be referred to as a second back pressure chamber (S2). As a result, the back pressure chamber (S1) is a space formed by a lower surface of the frame31and an upper surface of the second scroll33around the sealing member36, and the back pressure chamber (S1) will be described again together with a sealing member which will be described later.

On the other hand, the passage separation unit40is provided in an intermediate space10awhich is a through space formed between a lower surface of the electric motor unit20and an upper surface of the compression unit30to perform the role of preventing refrigerant discharged from the compression unit30from interfering with oil moving from an upper space10bof the electric motor unit20, which is an oil separation space, to a lower space10cof the compression unit30, which is an oil storage space.

To this end, the passage separation unit40according to the present embodiment includes a passage guide for dividing a space10ainto a space through which refrigerant flows (hereinafter, referred to as a refrigerant flow space) and a space through which oil flows (hereinafter, referred to as an oil flow space). Though the passage guide is able to divide the first space10ainto the refrigerant flow space and the oil flow space by the passage guide alone, in some cases, a plurality of passage guides may be combined to serve as the passage guide.

The passage separation unit according to the present embodiment includes a first passage guide410provided on the frame31to extend upward and a second passage guide420provided on the stator21to extend downward. The first passage guide410and the second passage guide420are overlapped in an axial direction such that the intermediate space10acan be divided into the refrigerant flow space and the oil flow space.

Here, the first passage guide410may be formed in an annular shape and fixedly coupled to an upper surface of the frame31, and the second passage guide420may be inserted into the stator21to extend from an insulator insulating a winding coil.

The first passage guide410includes a first annular wall portion411extended upward from the outside, a second annular wall portion412extended upward from the inside, and an annular surface portion413extended in a radial direction to connect between the first annular wall portion411and the second annular wall portion412. The first annular wall portion411may be formed higher than the second annular wall portion412, and a refrigerant through hole may be formed on the annular surface portion413to communicate with a refrigerant hole communicating to the intermediate space10afrom the compression unit30.

Furthermore, a first balance weight261is located at an inner side the second annular wall portion412, that is, in a direction of the rotation shaft, and the first balance weight261is coupled to the rotor22or the rotation shaft50to rotate. At this time, though the first balance weight261can stir refrigerant while rotating, the present disclosure may prevent refrigerant from moving toward the first balance weight261by the second annular wall portion412to suppress the refrigerant from being stirred by the first balance weight261.

The second passage guide420may include a first extension portion421extended downward from an outside of the insulator and a second extension portion422extended downward from an inside of the insulator. The first extension portion421is formed to overlap with the first annular wall portion411in an axial direction to perform the role of dividing the space into the refrigerant flow space and the oil flow space. The second extension portion422may not be formed as the need arises, but may not be overlapped with the second annular wall portion412in an axial direction even when formed or preferably formed at a sufficient distance in a radial direction to sufficiently flow refrigerant even when overlapped.

On the other hand, the upper portion of the rotation shaft50may be press-fitted to the center of the rotor22while the lower portion thereof is coupled to the compression unit30to be supported in a radial direction. As a result, the rotation shaft50transmits a rotational force of the electric motor unit20to the orbiting scroll33of the compression unit30. Then, the second scroll33eccentrically coupled to the rotation shaft50performs an orbiting motion with respect to the first scroll32.

A main bearing portion (hereinafter, referred to as a first bearing portion)51is formed in a lower half portion of the rotation shaft50to be inserted into the first shaft receiving hole312aof the frame31and supported in a radial direction, and a sub-bearing portion (hereinafter, referred to as a second bearing portion)52may be formed on a lower side of the first bearing portion51to be inserted into the second shaft receiving hole326aof the first scroll32and supported in a radial direction. Furthermore, the eccentric portion53may be formed between the first bearing portion51and the second bearing portion52to be inserted into the rotation shaft coupling portion333and coupled therewith.

The first bearing portion51and the second bearing portion52are coaxially formed to have the same axial center, and the eccentric portion53may be formed eccentrically in a radial direction with respect to the first bearing portion51or the second bearing portion52. The second bearing portion52may be formed to be eccentric with respect to the first bearing portion51.

An outer diameter of the eccentric portion53should be formed to be smaller than that of the first bearing portion51but larger than that of the second bearing portion52, and it may be advantageous to allow the rotation shaft50to pass through the shaft receiving holes312a,326aand the rotation shaft coupling portion333, respectively, and be coupled thereto. However, in the case where the eccentric portion53is not formed integrally with the rotation shaft50but formed using a separate bearing, the rotation shaft50may be inserted and coupled thereto without forming an outer diameter of the second bearing portion52to be smaller than that of the eccentric portion53.

In addition, an oil supply passage50afor supplying oil to each of the bearing portion and the eccentric portion may be formed along an axial direction within the rotation shaft50. The oil supply passage50amay be formed by grooving at a lower end of the rotation shaft50or a position approximately equal to the lower end or middle height of the stator21or higher than an upper end of the first bearing portion31as the compression unit30is positioned below the electric motor unit20. Of course, in some cases, it may be formed by passing through the rotation shaft50in an axial direction.

Furthermore, an oil feeder60for pumping oil filled in the lower space10cmay be coupled to a lower end of the rotation shaft50, that is, a lower end of the second bearing portion52. The oil feeder60includes an oil supply pipe61inserted into and coupled to the oil supply passage50aof the rotation shaft50and a blocking member62for receiving the oil supply pipe61to block the intrusion of foreign matter. The oil supply pipe61may be positioned to pass through the discharge cover34and to be immersed in oil in the lower space10c.

On the other hand, as shown inFIG. 3, a sliding portion oil feeding path (F1) connected to the oil supply passage50ato for supplying oil to each sliding portion is formed in each of the bearing portions51,52and the eccentric portion53of the rotation shaft50.

The sliding portion oil feeding path (F1) has a plurality of oil supply holes511,521,531penetrating from the oil supply passage50atoward an outer circumferential surface of the rotation shaft50, and a plurality of oil feeding grooves512,522,532communicating with the oil feeding holes511,521,531, respectively, to lubricate the bearing portions51,52and the eccentric portion53, respectively, on an outer circumferential surface of the bearing portions51,52and the eccentric portion53, respectively.

For example, the first oil feeding hole511and the first oil feeding groove512are formed in the first bearing portion51, the second oil feeding hole521and the second oil feeding groove522in the second bearing portion52, and the third oil feeding hole531and the third oil feeding groove532in the eccentric portion53, respectively. The first oil feeding groove512, the second oil feeding groove522, and the third oil feeding groove532are formed in an elongated groove shape in an axial direction or inclined direction, respectively.

Moreover, a first connection groove541and a second connection groove542are formed between the first bearing portion51and the eccentric portion53and between the eccentric portion53and the second bearing portion52, respectively. A lower end of the first oil feeding groove512communicates with the first connection groove541and an upper end of the second oil feeding groove522is connected to the second connection groove542. Accordingly, part of oil lubricating the first bearing portion51through the first oil feeding groove512flows down to be collected into the first connection groove541, and the oil flows into the first back pressure chamber (S1) to form a discharge pressure of the discharge pressure. Furthermore, oil lubricating the second bearing portion52through the second oil feeding groove522and oil lubricating the eccentric portion53through the third oil feeding groove532are collected to the second connection groove542to flow into the compression unit30through a space between a front end surface of the rotation shaft coupling portion333and the first end plate section321.

In addition, a small amount of oil that is sucked up toward an upper end of the first bearing portion51flows out of the bearing surface from an upper end of the first shaft receiving portion312of the frame31and flows down to an upper surface31aof the frame31along the first shaft receiving portion312, and then collected into the lower space10cthrough the oil passages (PO1, PO2) continuously formed on an outer circumferential surface of the frame31(or a groove communicating from the upper surface to the outer circumferential surface) and an outer circumferential surface of the first scroll32.

Moreover, oil discharged to the upper space10bof the casing10together with refrigerant from the compression chamber (V) is separated from refrigerant in the upper space10bof the casing10and collected into the lower space10cthrough the first oil passage (PO1) formed on an outer circumferential surface of the electric motor unit20and the second oil passage (PO2) formed on an outer circumferential surface of the compression unit30. At this time, a passage separation unit40is provided between the electric motor unit20and the compression unit30to move oil to the lower space10cand refrigerant to the upper space10bthrough different paths (PO1, PO2, PG1, PG2), respectively, without allowing oil separated from refrigerant in the upper space10band moved to the lower space10cto be intermixed again with refrigerant discharged from the compression unit20and moved to the upper space10b.

On the other hand, the second scroll33is formed with a compression chamber oil feeding path (F2) for supplying oil being sucked up through the oil supply passage50ato the compression chamber (V). The compression chamber oil feeding path (F2) is connected to the above-described sliding portion oil feeding path (F1).

The compression chamber oil feeding path (F2) includes a first oil feeding path371communicating between the oil feeding passage50aand the second back pressure chamber (S2) forming an intermediate pressure space, and a second oil feeding path372communicating with an intermediate pressure chamber between the second back pressure chamber (S2) and the compression chamber (V).

Of course, the compression chamber oil feeding path may be formed to directly communicate with the intermediate pressure chamber from the oil supply passage50awithout passing through the second back pressure chamber (S2). However, in this case, a refrigerant passage for communicating between the second back pressure chamber (S2) and the intermediate pressure chamber (V) should be additionally provided, and an oil passage for supplying oil to the oldham ring35located in the second back pressure chamber (S2) should be additionally provided As a result, a number of paths increases to complicate the processing. Therefore, in order to reduce the number of paths by integrating the refrigerant passage with the oil passage, it may be preferable to communicate the oil supply passage50awith the second back pressure chamber (S2) and communicate the second back pressure chamber (S2) with the intermediate pressure chamber (V).

To this end, the first oil feeding path371is formed with a first orbiting path portion371aformed up to the middle in the thickness direction from a lower surface of the second end plate portion331, and a second orbiting path portion371bformed toward an outer circumferential surface of the second end plate portion331from the first orbiting path portion371a, and a third orbiting path portion371cpenetrating toward an upper surface of the second end plate portion331from the second orbiting path portion371b.

Furthermore, the first orbiting path portion371ais formed at a position belonging to the first back pressure chamber (S1) and the third orbiting path portion371cis formed at a position belonging to the second back pressure chamber (S2). Furthermore, a pressure-reducing rod375is inserted into the second oil feeding path portion371bto reduce the pressure of oil moving from the first back pressure chamber (S1) to the second back pressure chamber (S2) through the first oil feeding path371. As a result, a cross-sectional area of the second orbiting path portion371bexcluding the pressure-reducing rod375is formed to be smaller than the first orbiting path portion371aor the third orbiting path portion371c.

Here, when an end portion of the third orbiting path portion371cis formed to be located on an inner side of the oldham ring35, that is, between the oldham ring35and the sealing member36, oil moving through the first oil feeding path371is blocked by the oldham ring35not to efficiently move to the second back pressure chamber (S2). Therefore, in this case, a fourth orbiting path portion371dmay be formed from an end portion of the third orbiting path portion371ctoward an outer circumferential surface of the second end plate portion331. The fourth orbiting path portion371dmay be formed as a groove on an upper surface of the second end plate portion331or formed as a hole inside the second end plate portion331as shown inFIG. 4.

The second oil feeding path372is formed with a first fixed path portion372ain a thickness direction on an upper surface of the second sidewall portion322, a second fixed path portion372ain a radial direction from the first fixed path portion372a, and a third fixed path portion372ccommunicating with the intermediate pressure chamber (V) from the second fixed path portion372b.

Reference numeral70in the drawing is an accumulator.

The foregoing lower compression scroll compressor according to this embodiment will be operated as follows.

In other words, when power is applied to the electric motor unit20, a rotational force is generated to the rotor21and the rotation shaft50to rotate, and as the rotation shaft50rotates, the orbiting scroll33eccentrically coupled to the rotation shaft50performs an orbiting motion by the oldham ring35.

Then, refrigerant supplied from the outside of the casing10through the refrigerant suction pipe15flows into the compression chamber (V), and the refrigerant is compressed and discharged to an inner space of the discharge cover34through the discharge ports325a,325bas the volume of the compression chamber (V) is reduced by the orbiting motion of the orbiting scroll33.

Then, the refrigerant discharged to the inner space of the discharge cover34is circulate in the inner space of the discharge cover34and moved to a space between the frame31and the stator21after reducing noise, and the refrigerant is moved to the upper space of the electric motor unit20through a gap between the stator21and the rotor22.

Then, after oil is separated from refrigerant in the upper space of the electric motor unit20, a series of processes of discharging the refrigerant to an outside of the casing10through the refrigerant discharge pipe16while collecting the oil into the lower space10cwhich is an oil storage space of the casing10through a passage between an inner circumferential surface of the casing10and the stator21and a passage between an inner circumferential surface of the casing10and an outer circumferential surface of the compression unit30are repeated.

At this time, oil in the lower space10cis sucked up through the oil supply passage50aof the rotation shaft50, and the oil lubricate the first bearing portion51, the second bearing portion52, and the eccentric portion53, respectively, through the respective oil feeding holes511,521,531and oil feeding grooves512,522,532.

The oil lubricating the first bearing portion51through the first oil feeding hole511and the first oil feeding groove512is collected into the first connection groove51between the first bearing portion51and the eccentric portion53, and the oil flows into the first back pressure chamber (S1). The oil almost forms a discharge pressure, and thus the pressure of the first back pressure chamber (S1) almost also forms the discharge pressure. Therefore, an center portion side of the second scroll33may be supported in an axial direction by the discharge pressure.

On the other hand, the oil of the first back pressure chamber (S1) is moved to the second back pressure chamber (S2) through the first oil feeding path371due to a pressure difference from the second back pressure chamber (S2). At this time, the pressure-reducing rod375is provided in the second orbiting path portion371bconstituting the first oil feeding path371, and thus a pressure of the oil moving toward the second back pressure chamber (S2) is reduced to an intermediate pressure.

Furthermore, the oil moving to the second back pressure chamber (intermediate pressure space) (S2) moves to the intermediate pressure chamber (V) through the oil feeding path372due to a pressure difference from the intermediate pressure chamber (V) while at the same time supporting an edge portion of the second scroll33. However, when the pressure of the intermediate pressure chamber (V) is higher than that of the second back pressure chamber (S2) during the operation of the compressor, refrigerant moves to the second back pressure chamber (S2) through the second oil feeding path372from the intermediate pressure chamber (V). In other words, the second oil feeding path372serves as a path for moving refrigerant and oil in an intersecting manner due to a difference between the pressure of the second back pressure chamber (S2) and the pressure of the intermediate pressure chamber (V).

Meanwhile, as described above, the air conditioner according to the embodiment of the present disclosure is provided with a cooling cycle device capable of performing cooling or heating using a phase change of circulating refrigerant.

The cooling cycle device includes a compressor, a condensing unit connected to a discharge side of the compressor to condense compressed refrigerant, an expansion unit configured to expand the refrigerant condensed in the condensing unit, an evaporation unit connected to a suction side of the compressor to evaporate the refrigerant expanded in the expansion unit, and an injection unit provided between the expansion unit and the evaporation unit to inject part of the refrigerant expanded in the expansion unit into the intermediate pressure chamber of the compressor other than the evaporation unit. The cooling cycle device will be described again later while describing the operation of an air conditioner, and first of all, the injection unit in the lower compression scroll compressor applied to the cooling cycle device of this embodiment will be described.

According to the present embodiment, as shown inFIG. 1, due to the characteristics of the lower compression scroll compressor, the compression unit30is located at a lower half of the casing10, that is, the cylindrical shell11, and above all, the first scroll31constituting the compression chamber constitutes a lower portion of the compression unit30. Accordingly, as shown inFIG. 5, an injection pipe connection hole11ais formed around a lower end of the cylindrical shell11to allow an injection pipe (more particularly, a connection pipe) (L4) which will be described later to be inserted and coupled thereto, and the intermediate member11bmay be coupled to the injection pipe connection hole11afor welding between the injection pipe (L4) and the cylindrical shell11. As a result, even when the injection pipe (L4) communicates with an inner space of the casing10having a high pressure, it may be possible to suppress refrigerant from leaking.

Furthermore, an injection passage391is formed in the first end plate portion321of the first scroll32to communicate with an injection unit which will be described later through an injection connection hole11aof the cylindrical shell11. The injection passage391includes a first passage391aformed in a radial direction from an outer circumferential surface of the first end plate portion321toward the center and a second passage391bpenetrated from a center-side end portion of the first passage391atoward the intermediate pressure chamber (Vm).

Here, an outlet end of the second passage391bmay be formed to communicate with the suction chamber (Vs), but in this case, refrigerant injected through the injection passage391(hereinafter, referred to as injection refrigerant) may have a relatively higher pressure than that of refrigerant being sucked (hereinafter, referred to as suction refrigerant), thereby causing suction loss. Therefore, the outlet end of the second passage391bmay be preferably communicated with the intermediate pressure chamber (Vm) having a higher pressure than the suction chamber (Vs).

Furthermore, though the outlet end of the second passage391bis preferably formed around the discharge port to reduce compression loss, the outlet end of the second passage391bmay be more preferably formed to communicate with the intermediate pressure chamber (Vm) typically having a lower pressure than the bypass hole381. However, when a plurality of bypass holes381are formed along the path of the compression chamber (V), the outlet end of the second passage391bmay not necessarily communicate with the intermediate pressure chamber having a lower pressure than the bypass hole381. In other words, in this case, the second passage391bmay communicate with the intermediate pressure chamber (Vm) between the bypass holes381.

Meanwhile, a cooling cycle device of an air conditioner to which a lower compression scroll compressor having the above-described injection unit is applied is as follows.

In other words, as described above, the cooling cycle device includes a compression unit, a condensing unit, an expansion unit, an evaporation unit, and an injection unit. Here, the compression unit may be configured with a compressor1, the condensing unit with a condenser2and a condensing fan2a, the expansion unit with a first expansion valve3aand a second expansion valve3b, the evaporation unit with an evaporator4, and the injection unit with an injection expansion valve5and an injection heat exchanger6, respectively.

Furthermore, the compressor1, the condenser2, the first expansion valve3aand the second expansion valve3b, the evaporator4, the injection expansion valve5, and the injection heat exchanger6are connected to the refrigerant pipe (L) for guiding the flow of refrigerant to form a closed loop, and among them, the injection expansion valve5and the injection heat exchanger6are connected to the refrigerant pipe (L) through the bypass pipe (L3) and the injection pipe (L4) to form an injection cycle.

Here, the injection expansion valve5may be configured with a valve capable of adjusting a degree of expansion by controlling its opening degree.

In addition, between a discharge side of the compressor1and an inlet of the condenser2, a refrigerant switching valve7for switching a flow direction of the refrigerant is provided. Accordingly, when the air conditioner is in a cooling operation, the outdoor heat exchanger may function as a condenser and the indoor heat exchanger as an evaporator. On the contrary, when the air conditioner is in a heating operation, the indoor heat exchanger may function as a condenser and the outdoor heat exchanger as an evaporator.

As described above, the compressor1is provided with a lower compression type axial through scroll compressor in which the compression unit30is located below the electric motor unit20while the rotation shaft50is coupled through the second scroll33constituting an orbiting scroll. The compressor has been described in detail above.

The condenser2, the first expansion valve3aand the second expansion valve3b, and the evaporator4are generally known constructions, and a detailed description thereof will be omitted. However, the injection expansion valve5may be configured with a valve capable of adjusting an opening amount to control a flow amount of refrigerant, and the injection heat exchanger6may be a double pipe heat exchanger having an outer pipe and an inner pipe.

As shown inFIG. 6, an inlet of an outer pipe6ais connected to an outlet of the first expansion valve3athrough the first refrigerant pipe (L1), and an outlet of the outer pipe6ais connected to an inlet of the second expansion valve3band the second refrigerant pipe (L2).

Furthermore, an inlet of an inner pipe6bof the injection heat exchanger6is connected to a bypass pipe (L3) branched from the first refrigerant pipe (L1), and an outlet of the inner pipe6bmay be connected to an injection passage391of the compressor1, which will be described later, through an injection pipe (L4).

In addition, the injection expansion valve5described above may be connected and provided at the middle of the bypass pipe (L3).

Thus, liquid refrigerant that has been primarily expanded while passing through the first expansion valve3aflows into the outer pipe6a, and the refrigerant is bypassed to the branched bypass pipe (L3) to pass through the injection expansion valve5while moving to the expansion valve3b. The refrigerant passing through the injection expansion valve5is secondarily expanded in the injection expansion valve5to a state in which the liquid refrigerant and the gas refrigerant are mixed.

The liquid refrigerant and the gas refrigerant that have passed through the injection expansion valve5flow into the inner pipe6bof the injection heat exchanger6, and the liquid refrigerant and the gas refrigerant flowing into the inner pipe6bexchange heat with the primarily expanded high-temperature refrigerant of the outer pipe6ato absorb heat from the refrigerant of the outer pipe6ato be converted into gas refrigerant, and the secondarily expanded gas refrigerant is guided to the injection passage391through the injection pipe (L4), which will be described later, and injected into the intermediate pressure chamber (Vm).

A pressure-enthalpy diagram (P-H diagram) of a refrigerant system circulating through the air conditioner will be described with reference toFIGS. 5 and 7. This is based on a heating operation, and thus the indoor heat exchanger operates as the condenser2and the outdoor heat exchanger as the evaporator4.

In other words, refrigerant (state A) sucked into the compressor1is compressed by the compressor1and mixed with refrigerant injected into the compressor1through the injection passage (L4). The mixed refrigerant indicates the state of B. The process in which refrigerant is compressed from the state A to the state B is referred to as a “one- stage compression.”

The refrigerant in the state B is compressed again, indicating the C state. The process in which the refrigerant is compressed from the state B to the state C is referred to as a “two-stage compression.” Then, the refrigerant indicates the state of D when the refrigerant is discharged in the state of C to flow into the indoor heat exchanger serving as the condenser2, and discharged from the condenser2.

The refrigerant that has passed through the condenser2is “primarily expanded” through the first expansion valve3ato become a state D, and the primarily expanded refrigerant passes through the outer pipe6aof the injection heat exchanger6and then most of the refrigerant (circulating refrigerant) moves in a direction toward the second expansion valve3bwhile part of the refrigerant (injection refrigerant) is bypassed to the bypass pipe (L3) while opening the injection expansion valve5. At this time, the circulating refrigerant is heat-exchanged with the injection refrigerant passing through the inner pipe6bof the injection heat exchanger6while passing through the outer pipe6aof the injection heat exchanger6to be re-condensed to a state E, which is referred to as “secondary condensation.” On the contrary, the injection refrigerant is “injection-expanded” to become a state G, and then “injection-evaporated” while passing through the inner pipe6bof the injection heat exchanger6to secure a degree of superheat.

A series of processes in which the circulating refrigerant that has passed through the second expansion valve3bpasses through the evaporator4to become a state A and is sucked into the suction chamber (Vs) of the compressor1through the suction pipe15while the injection refrigerant that has passed through the injection heat exchanger is injected into the intermediate pressure chamber (Vm) of the compressor through the injection pipe (L4) are repeated.

In the scroll compressor according to the present embodiment as described above, a series of processes in which refrigerant is guided from the cooling cycle to the suction groove324of the first scroll32through the suction pipe15, and the refrigerant flows into the intermediate pressure chamber (Vm) by passing through the suction chamber (Vs) through the suction groove, and compressed while moving toward the center between the second scroll33and the first scroll32by an orbiting motion of the second scroll33and then discharged to an inner space of the discharge cover34through the discharge port325of the first scroll32in the discharge chamber (Vd), and the refrigerant is discharged to the intermediate space10aof the casing10through the first refrigerant passage (PG1) and then moved to the upper space10bthrough the second refrigerant passage (PG2) and then discharged to the refrigeration cycle through the discharge pipe16are repeated.

At this time, the gas refrigerant discharged from the compressor1is converted into liquid refrigerant after passing through the condenser2to pass through the first expansion valve3a, and the liquid refrigerant that has passed through the first expansion valve3ais passed through the injection heat exchanger (supercooling device)6and then at least partially passed to the bypass pipe (L3), and the injection refrigerant is passed again through the injection heat exchanger6through the injection expansion valve5and injected into the intermediate pressure chamber (Vm) of the compressor1through the injection pipe (L4).

However, the injection refrigerant expands while passing through the injection expansion valve5to become a state in which the low-temperature low-pressure liquid refrigerant and the gas refrigerant are mixed together, and the injection refrigerant absorbs heat from the circulating refrigerant moving in a direction of the evaporator through the outer pipe6aof the injection heat exchanger6while passing through the inner pipe6bof the injection heat exchanger6. Accordingly, the injection refrigerant is converted into the gas refrigerant to move to the injection passage391through the injection pipe (L4) while the circulating refrigerant moves to the evaporator4in a state of being supercooled to a lower temperature.

Here, the injection refrigerant flowing into the injection passage391moves along the first passage391aand the second passage391bof the first scroll32and flows into the intermediate pressure chamber (Vm). At this time, as the compression chamber (V) is formed on an upper surface of the first scroll32, the first scroll itself is heated by compression heat. Moreover, the first scroll32is also heated by the refrigerant discharged into the inner space of the discharge cover34, and the first scroll32is heated to a high temperature as a whole. Accordingly, as the injection refrigerant is heat-exchanged with the first scroll32in the process of passing through the first passage391aand the second passage391bof the first scroll32and heated by heat conduction, a degree of superheat with respect to the injection refrigerant may be increased. thereby reducing the possibility that the liquid refrigerant flows into the compression chamber.

Meanwhile, a scroll compressor according to another embodiment of the present disclosure and an air conditioner having the scroll compressor will be described as follows.

In other words, the foregoing embodiment relates to a case where the injection unit is configured with one injection unit, but the present embodiment relates to a case where the injection unit is configured with two injection units, namely, a first injection unit and a second injection unit. Of course, the injection unit may be configured with two or more, and even in this case, it is substantially similar to a case of two to be described in the following.

Furthermore, the basic configuration of a compressor according to the present embodiment is the same as the foregoing embodiment. However, as shown inFIGS. 8 and 9, in the compressor according to the present embodiment, the first injection passage395and the second injection passage396are formed in the first end plate portion321of the first scroll32.

Here, the first injection passage395and the second injection passage396are configured with first passages395a,396aand second passages395b,396b, respectively, and an outlet of the second passage (first injection-side second passage)395bof the first injection passage395and an outlet of the second passage (second injection-side second passage)396bof the second injection passage396are communicated with different intermediate pressure chambers (Vm1, Vm2), respectively.

In this case, as shown inFIG. 8, the outlet of the first injection-side second passage395bmay be formed to be positioned prior to completing a suction stroke, and the outlet of the second injection-side second flow path396bsubsequent to completing the suction stroke, and more precisely, a rotation angle (β) between the first injection-side second passage395band the second injection-side second passage396bmay be formed within a range of about 150 to 200 degrees in the compression advancing direction of the refrigerant, and preferably formed to have a phase difference of about 170°.

In addition, the basic configuration of the first injection unit and the second injection unit is similar to the basic configuration of the above-described injection unit. For example, as shown inFIG. 10, the first injection unit8includes a first injection expansion valve81and a first injection heat exchanger82, and the second injection unit9includes a second injection expansion valve91and a second injection heat exchanger92. The first injection heat exchanger82and the second injection heat exchanger92may be formed in a double pipe structure such as the above-described injection heat exchanger6.

Furthermore, a first injection pipe (L41) connected to the first injection heat exchanger82may be connected to the first injection passage395, and a second injection pipe (L42) connected to the second injection heat exchanger92may be connected to the second injection passage396.

Here, in the condenser2, the first injection unit8is located on an upstream side of the second injection unit9, that is, on a side of the condenser2, with respect to the direction of the evaporator. Accordingly, the first expansion valve3ais connected to an upstream side of the first injection unit8, and the second expansion valve3bis connected to a downstream side of the second injection unit9, respectively.

Moreover, the first injection pipe (L41) is connected to an inner pipe (hereinafter, first inner pipe)82bof the first injection heat exchanger82and an outer pipe (hereinafter, first outer pipe)82aconstituting the first injection heat exchanger82together with the first inner pipe82bis connected to an outlet of the first injection expansion valve81by the first bypass pipe (L31).

Besides, the second injection pipe (L42) is connected to an inner pipe (hereinafter, second inner pipe)92bof the second injection heat exchanger92and an outer pipe (hereinafter, second outer pipe)92aconstituting the second injection heat exchanger92together with the second inner pipe92bis connected to an outlet of the second injection expansion valve91by the second bypass pipe (L32). The inlet of the second injection expansion valve91is connected to an outlet of the first outer pipe82a.

The operation of the scroll compressor and the air conditioner having the scroll compressor according to the present embodiment as described above is substantially similar to the foregoing embodiment. In this embodiment, however, a plurality of injection units are provided, and thus refrigerant is first injected through the first injection unit8communicating with the upstream side with respect to the compression advancing direction of the refrigerant, and refrigerant is injected later through the second injection unit9relatively communicating with the downstream.

As a result, the compression performance may be further improved as two injections proceed at a constant interval in one cycle in which the refrigerant is sucked and discharged. The effect of this may be confirmed through the P-H diagram illustrated inFIG. 12. This will be replaced with the description of the P-H diagram in the foregoing embodiment.

The foregoing description is merely embodiments for implementing a scroll compression compressor according to the present disclosure, and the present disclosure may not be necessarily limited to the foregoing embodiments, and it will be understood by those skilled in the art that various modifications can be made without departing from the gist of the invention as defined in the following claims.