JP7321018B2 - Compressors, outdoor units and air conditioners - Google Patents

Description

The present invention relates to a compressor for compressing fluid, an outdoor unit, and an air conditioner.

A rotary compressor contains an electric motor and a compression mechanism in an airtight container, and the electric motor rotates a rotating body (roller) that constitutes the compression mechanism via a rotating shaft, thereby compressing fluid in a compression chamber. Bearings that rotatably support the rotating shaft are provided above and below the compression mechanism.

Refrigerating machine oil used as lubricating oil is stored in the bottom of the sealed container, is sucked up through the inside of the rotating shaft, and is supplied to the compression mechanism and upper and lower bearings. The refrigerating machine oil supplied to the lower bearing returns directly to the oil reservoir at the bottom of the closed container, but the refrigerating machine oil supplied to the upper bearing is the fluid compressed by the compression mechanism between the electric motor and the compression mechanism. It is discharged upwards into the discharge space.

Most of the refrigerating machine oil discharged into the discharge space falls and returns to the oil reservoir, but part of it is discharged out of the sealed container together with the high-pressure fluid discharged from the compression mechanism. If the discharged amount increases, the oil level in the oil sump will drop, and the reliability of the compressor will drop.

In view of such problems, an annular groove is provided in the upper end of the upper bearing, an oil discharge hole extending radially from the annular groove is provided, and the diameter of the oil discharge hole is made larger than the radial width of the annular groove. A technique has been proposed to reduce the amount of oil discharged to the outside by reducing the passage resistance to the oil discharge hole from the discharge passage upward from the groove (see, for example, Patent Document 1).

Japanese Patent No. 4992496

In the above conventional technology, the amount of oil discharged to the outside is reduced by slanting the oil discharge hole downward, but the refrigerating machine oil is also discharged upward into the discharge space from the upper opening of the annular groove. Therefore, there is a problem that the amount discharged to the outside cannot be sufficiently reduced.

In view of the above problems, the present invention provides a compressor for compressing fluid,
an electric motor;
a rotating shaft driven by an electric motor and having an eccentric portion;
a container positioned below the electric motor and having a compression chamber for compressing the fluid;
a rotating body provided around the eccentric portion and rotating in the compression chamber while being in contact with the inner peripheral surface of the compression chamber;
a partition member that contacts the rotating body and partitions the compression chamber into two spaces;
an elastic body that presses one end of the partition member,
The container comprises a side body that constitutes the side of the compression chamber and is fitted with a partition member and an elastic body, and two bearings that close openings at both ends of the compression chamber and rotatably support the rotating shaft. including
Of the two bearings, the upper bearing on the motor side has a spiral groove for upwardly supplying the oil stored in the lower part of the container, and a spiral groove that is continuous with the spiral groove and discharges the supplied oil through the spiral groove. A compressor is provided having an oil drain hole for cooling, the oil drain hole sloping downwardly into the space between the motor and the container about the axis of rotation.

According to the present invention, it is possible to sufficiently reduce the amount of refrigerating machine oil discharged to the outside while ensuring the supply of refrigerating machine oil to required locations.

The figure which showed the structural example of an air conditioner. The figure which showed the structural example of an outdoor unit. The figure which showed the structural example of a compressor. The figure which showed the 1st example of the direction where an oil drain hole extends. The figure which showed the 2nd example of the direction where an oil drain hole extends. The figure which showed an example of the position of the oil discharge hole continuously provided in the spiral groove. The figure which showed the 4th example of the direction where an oil drain hole extends. The figure which showed the 5th example of the direction where an oil drain hole extends.

The compressor according to the present embodiment can be used alone as a device for compressing fluid, and can be mounted on any device or system. explain.

FIG. 1 is a diagram showing a configuration example of an air conditioner. An air conditioner includes one or more indoor units installed in the same space and one or more outdoor units installed outside the space. The apparatus illustrated in FIG. 1 includes one indoor unit 10 installed indoors and one outdoor unit 11 installed outdoors.

The indoor unit 10 and the outdoor unit 11 are connected by two pipes 12 , and a refrigerant is configured to circulate in the pipes 12 . Refrigerants are heat carriers used to transfer heat, for example hydrofluorocarbons (HFCs), which have no ozone-depleting effect, are used.

The indoor unit 10 sucks indoor air, cools or warms the indoor air with a circulating refrigerant, and blows out the cooled or warmed air. By repeating this, the room is cooled or warmed. The outdoor unit 11 supplies the refrigerant to the indoor unit, collects the refrigerant from the indoor unit, heats or cools the refrigerant, and supplies the refrigerant to the indoor unit 10 again.

FIG. 2 is a diagram showing a configuration example of the outdoor unit 11. As shown in FIG. The outdoor unit 11 includes a fan 20 that sucks in outside air and blows it out, a heat exchanger 21 that warms or cools the sucked air, a compressor 22 that circulates a refrigerant between the indoor unit 10 and the outdoor unit 11, and an outdoor unit. A control board 23 for controlling the machine 11 and an expansion valve 24 are provided. In addition, the outdoor unit 11 includes a temperature sensor that measures the outside air temperature, a sensor that measures the current supplied to the compressor 22, a sensor that measures the flow rate of the refrigerant, a sensor that measures the pressure of the refrigerant, a four-way valve, an accumulator, and the like. ing.

The control board 23 receives instructions from the indoor unit 10, operates or stops the outdoor unit 11, and based on the notified information, controls the fan 20 and the compressor 22 so that the indoor temperature reaches the set temperature. By changing the operating load, the temperature of the refrigerant supplied to the indoor unit 10, the flow rate of the refrigerant, and the like are adjusted. Expansion valve 24 is used to expand the compressed refrigerant and lower the temperature of the refrigerant.

Here, the operation of the outdoor unit 11 in the air conditioner in operation will be briefly described. When the operation of the outdoor unit 11 is started, the compressor 22 is started, and circulation of refrigerant between the indoor unit 10 and the outdoor unit 11 is started.

When the air conditioner is used for cooling, when the compressor 22 compresses and discharges refrigerant, the high-temperature, high-pressure refrigerant is supplied into the heat exchanger 21 . The refrigerant exchanges heat with the outside air sucked in by the fan 20 and is cooled. After cooling, the refrigerant is expanded by the expansion valve 24 to lower its temperature and is sent from the outdoor unit 11 to the indoor unit 10 through the pipe 12 .

The indoor unit 10 includes a fan, a heat exchanger, and a control board. Refrigerant is supplied to the inside of the heat exchanger, and heat is exchanged with indoor air sucked by the fan. The air is cooled by the refrigerant and blown indoors.

Refrigerant is returned to compressor 22 through line 12 . This operation is repeated to cool the room to the set temperature with the blown cold air.

When the air conditioner is used for heating, the operation is the reverse of that for cooling. sent to machine 10. In the indoor unit 10, refrigerant is supplied into the heat exchanger, and heat is exchanged with indoor air sucked in by the fan. The air is warmed by the refrigerant and blown out into the room.

The refrigerant gives heat to the air, is cooled, and is sent to the outdoor unit 11 through the pipe 12 . In the outdoor unit 11 , the expansion valve 24 expands the condensed high-pressure refrigerant. As a result, the refrigerant is in a state of low temperature and low pressure. After that, it is supplied into the heat exchanger 21 , heat-exchanged with the outside air sucked in by the fan 20 , and then returned to the compressor 22 . This operation is repeated to heat the room to the set temperature with the warm air blown out.

FIG. 3 is a diagram showing a configuration example of the compressor 22. As shown in FIG. Compressor 22 is a rotary compressor with a small number of parts, and includes electric motor 40 and compression mechanism 50 housed in closed container 30 . Electric motor 40 is configured to rotationally drive compression mechanism 50 via rotating shaft 31 and includes a stator 41 and a rotor 42 .

The stator 41 is composed of an iron core, coils, or the like, and the rotor 42 includes a permanent magnet. When an electric current is passed through the coils of the stator 41, an electromagnet is formed. rotate. Note that this is an example, and the stator 41 may include permanent magnets, and the rotor 42 may be composed of an iron core, coils, or the like.

The stator 41 is provided with an insulator (insulator) 43 for insulating the current so that it does not flow to anything other than the coil. The insulator 43 extends in the same vertical direction as the direction in which the rotating shaft 31 extends, is longer than the stator 41 in the vertical direction, and has a lower end serving as the lower end of the electric motor 40 . A gap exists between the sealed container 30 and the stator 41 and between the stator 41 and the rotor 42 . In addition to the gaps described above, the electric motor 40 may be provided with a through hole connecting the primary space 32 and the secondary space 33 in order to reduce the flow velocity of the coolant.

The compression mechanism 50 is arranged below the electric motor 40 with a space therebetween. A space between the electric motor 40 and the compression mechanism 50 is a primary space 32 , and a space above the electric motor 40 is a secondary space 33 . Refrigerating machine oil is stored in the lower portion of the compression mechanism 50 as oil used for lubrication of sliding portions of the compression mechanism 50 and for sealing compression chambers, which will be described later.

The compressor 22 has a gas-liquid separator 34 outside the closed container 30 . The gas-liquid separator 34 is connected to the closed container 30 , separates the liquid refrigerant, and supplies only the gas refrigerant into the closed container 30 .

The refrigerant supplied into the sealed container 30 enters the compression mechanism 50 , is compressed, becomes a high-temperature, high-pressure refrigerant, and is discharged to the primary space 32 . The rotating shaft 31 is driven by an electric motor 40 and has an eccentric portion. The eccentric portion is a disk-shaped member attached so as to surround the circumference of the rotating shaft 31, and the center of gravity of the eccentric portion is located at a position deviated from the center of the shaft.

The compression mechanism 50 is arranged below the electric motor 40 , is provided around a container having a compression chamber 51 for compressing the refrigerant, and around the eccentric portion of the rotating shaft 31 and is in contact with the inner peripheral surface of the compression chamber 51 . and a rotating body (roller) that rotates in the compression chamber 51 . The compression mechanism 50 also includes a partition member (vane) that contacts the roller and partitions the compression chamber 51 into two spaces, and an elastic body that presses one end of the vane. The elastic body can be, for example, a spring, but is not limited to this, and may be rubber.

The container constitutes the side of the compression chamber 51, and includes a side body (cylinder) 52 to which vanes and springs are mounted, and openings at both ends (upper and lower) of the compression chamber 51 are closed, and the rotating shaft 31 can be rotated. and two bearings (upper bearing, lower bearing) 53, 54 that support the The upper bearing 53 is provided with a muffler (silencer) 55 for silencing the sound generated when the high-pressure refrigerant is discharged. The silencer 55 has a hole through which the refrigerant passes. The high-pressure refrigerant compressed in the compression chamber 51 is discharged into the silencer 55 and discharged into the primary space 32 through holes provided in the silencer 55 .

The refrigerant discharged into the primary space 32 flows into the secondary space 33 through the gap between the sealed container 30 and the stator 41 and the gap between the stator 41 and the rotor 42 . A discharge pipe 35 that connects the secondary space 33 and the outside is provided at the top of the sealed container 30 , and the refrigerant that has flowed into the secondary space 33 is discharged to the outside through the discharge pipe 35 .

The refrigerating machine oil stored in the lower portion of the compression mechanism 50 is provided with helical blades (spiral shaft) in a shaft hole 36 formed in the longitudinal direction from the lower end of the rotating shaft 31. At least a portion, all of the lower bearing 54, and at least a portion of the cylinder 52 are immersed in refrigerating machine oil. The refrigerating machine oil is sucked into the shaft hole 36 as the spiral shaft rotates as the rotating shaft 31 rotates.

The refrigerator oil sucked into the shaft hole 36 is supplied between the rotating shaft 31 and the lower bearing 54, between the rotating shaft 31 and the roller, between the rotating shaft 31 and the upper bearing 53, and the like. The upper bearing 53 has a helical (spiral) groove 56 on its inner surface for supplying the refrigerating machine oil sucked into the shaft hole 36 further upward. The spiral groove 56 supplies refrigerating machine oil between the rotary shaft 31 and the upper bearing 53 , and excess oil is discharged to the outside of the upper bearing 53 .

The upper bearing 53 has an oil drain hole 57 for draining excess oil. The oil discharge hole 57 continues to the spiral groove 56 and extends obliquely downward toward the primary space 32 . The refrigerator oil supplied through the spiral groove 56 is also supplied between the rotating shaft 31 at the upper end of the oil discharge hole 57 and the upper bearing 53 , and excess oil is discharged from the oil discharge hole 57 .

The upper end portion of the upper bearing 53 is a portion where uneven contact is likely to occur due to whirling of the rotating shaft 31 . However, not all of the oil is discharged from the oil discharge hole 57, and the oil can be appropriately supplied to the upper end portion of the upper bearing 53 as well. Therefore, the reliability of the upper end portion of the upper bearing 53 is not lost.

Further, since the oil discharge hole 57 extends downward into the primary space 32 between the electric motor 40 and the upper bearing 53, the silencer 55 and the upper bearing 53 below the oil discharge hole 57 expand in the radial direction. It discharges onto the closure that closes the upper opening of the cylinder 52 and does not discharge toward the motor 40 above. Therefore, the flow of the refrigerant moving from the primary space 32 to the secondary space 33 through the gaps of the electric motor 40 (the gap between the closed container 30 and the stator 41, the gap between the stator 41 and the rotor 42, etc.) can reduce the amount of refrigerating machine oil discharged along.

The refrigerating machine oil discharged onto the silencer 55 flows toward the edge of the closed portion of the circular upper bearing 54 when viewed from above, drops through the oil return hole provided in the edge, and flows to the bottom of the sealed container 30. returns to the sump of the refrigerating machine oil stored in .

A small amount of the refrigerating machine oil discharged from the oil discharge hole 57 is carried to the secondary space 33 together with the high-pressure refrigerant and discharged to the outside of the sealed container 30 . The flow path through which the refrigerant circulates is a closed space, and the refrigerating machine oil contained in the refrigerant returns to the compressor again and is used to reduce friction when rollers contact the cylinder 52 or when vanes slide. be done.

FIG. 4 is a diagram showing a first example of the direction in which the oil drain hole 57 extends. The oil drain hole 57 may be any hole as long as it is continuous with the spiral groove 56 and extends downward toward the primary space 32. As shown in FIG. It is desirable that the insulator 43 provided in 41 is opened downward from the lower end thereof. This is because the refrigerating machine oil discharged from the oil discharge hole 57 is prevented from adhering to the insulator 43 and is prevented from being transported to the secondary space 33 together with the high-pressure refrigerant.

More preferably, the oil discharge hole 57 opens toward the closed portion of the upper bearing 53 and the silencer 55 . If the opening is directed between the closed portion of the upper bearing 53 and the lower end of the insulator 43 , the refrigerating machine oil is discharged toward the inner surface of the sealed container 30 . There is a gap between the closed container 30 and the stator 41, and a high-pressure refrigerant flows through the gap. Then, the refrigerating machine oil adhering to the inner surface of the sealed container 30 is carried to the secondary space 33 by the flow of the high-pressure refrigerant, and less refrigerating machine oil returns to the oil reservoir.

FIG. 5 is a diagram showing a second example of the direction in which the oil drain hole 57 extends. A substantially cross-shaped silencer 55 is provided above the closing portion 58 of the upper bearing 53 . Silencer 55 reduces the sound of high pressure refrigerant as it is discharged from compression chamber 51 . The reason why the silencer 55 is substantially cruciform is that a bolt hole for inserting a bolt for connecting the upper bearing 53 to the cylinder 52 or the like is provided in a concave portion 59 formed between each of the portions projecting in four directions. , and the purpose is to improve the silencing effect by repeating the compression and expansion of the flow path of the gas discharged from the compression mechanism 50 . The silencer 55 has a coolant discharge hole 60 through which the coolant is discharged to the primary space 32 .

One or more oil return holes 61 are provided in the edge of the closed portion 58 of the upper bearing 53, and the refrigerating machine oil discharged from the oil discharge hole 57 flows over the silencer 55 and the closed portion 58, and flows through the oil return hole. Drops from 61 into the oil pool.

The silencer 55 slopes downward from the center to the edge and the closure 58 also slopes downward from the center to the edge. Therefore, no matter where the refrigerating machine oil falls, it can be guided toward the edge of the closing portion 58 . Therefore, the oil drain hole 57 needs to extend downward toward the primary space 32 with an inclination with respect to the vertical direction, but it can extend in any direction with respect to the horizontal direction.

However, when the refrigerating machine oil is discharged onto the silencer 55, the oil that flows over the silencer 55 and the oil that flows down into the recesses 59 on both sides of the silencer 55 are divided into the oil that flows through each of the recesses 59, thereby expanding the flow range of the refrigerating machine oil. It takes time to collect the refrigerator oil in the oil sump. During this time, the oil level in the oil pool drops, the amount of oil sucked up by the shaft hole 36 decreases, and an appropriate amount of refrigerating machine oil cannot be supplied to each location.

Therefore, the oil drain hole 57 can be provided so that the direction extending in the horizontal direction extends toward any one of the four recesses 59 . As a result, the flow range of the refrigerating machine oil can be limited, and the discharged refrigerating machine oil can be quickly collected in the oil sump.

FIG. 6 is a diagram showing an example of positions of oil discharge holes provided continuously with the spiral groove. The oil discharge hole 57 is provided on the upper side of the upper bearing 53 so as to be continuous with the spiral groove 56 . It is desirable that the diameter of the oil discharge hole 57 is larger than the width of the spiral groove 56 . This limits the amount of refrigerating machine oil supplied between the upper bearing 53 and the rotating shaft 31 above the connecting portion between the oil discharge hole 57 and the spiral groove 56 , and is discharged from the upper end of the upper bearing 53 . , to reduce the amount of refrigerating machine oil carried to the secondary space 33 .

Since the rotary shaft 31 rotates in a predetermined direction, the position of the oil discharge hole 57 in the portion that continues to the spiral groove 56 is desirably behind the center of the width of the spiral groove 56 with respect to the rotation direction. The spiral groove 56 is spirally formed on the inner surface of the upper bearing 53 from the lower end to the upper end in a direction opposite to the rotating direction of the rotating shaft 31 . Therefore, the position behind the center of the width of the spiral groove 56 is a position closer to the side where the spiral groove 56 is formed toward the upper end from the center. In the example shown in FIG. 6, the rotary shaft 31 rotates in the direction indicated by the arrow A, and an oil discharge hole 57 continuous with the spiral groove 56 is provided at a position shifted in the direction opposite to the direction indicated by the arrow A. ing.

Since the refrigerating machine oil rising through the spiral groove 56 moves in a direction opposite to the rotation direction of the rotating shaft 31, by providing the oil discharge hole 57 at a position behind the center of the width of the spiral groove 56, It becomes easier to enter the oil discharge hole 57 . Therefore, more refrigerating machine oil can be discharged from the oil discharge hole 57, and the amount of refrigerating machine oil discharged from the upper end portion of the upper bearing 53 can be reduced.

FIG. 7 is a diagram showing a third example of the direction in which the oil drain hole 57 extends. Similarly to the example shown in FIG. 5, FIG. 7 also illustrates the direction in which the oil drain hole 57 extends in the horizontal direction. The oil discharge hole 57 extends above one of the four directions projecting portions of the substantially cross-shaped silencer 55 so as to discharge the refrigerating machine oil. Here, the oil discharge hole 57 extends so as to discharge the refrigerating machine oil above the projecting portion of the silencer 55 , but it is not limited to this and may extend toward the recess 59 .

In this example, no oil return hole 61 exists at the edge of the closed portion 58 of the upper bearing 53 in the direction in which the oil discharge hole 57 extends. For this reason, the refrigerating machine oil collides with the wall provided on the outer peripheral side of the edge, splits into two, moves in the circumferential direction along the wall surface, drops from the nearby oil return hole 61, You will return to the pool. By splitting into two, the amount of refrigerating machine oil flowing in one direction decreases, the flow speed becomes slower, and it takes time to collect the refrigerating machine oil in the oil reservoir.

Therefore, the above wall is provided with a convex portion toward the central portion where the rotating shaft 31 exists, and is used as a guide wall 62 that guides the flow in one direction. The guide wall 62 has a surface that is inclined with respect to the direction in which the oil drain hole 57 extends. In addition, the surface is not limited to a flat surface, and may be a curved surface.

In the example shown in FIG. 7, the refrigerating machine oil discharged from the oil discharge hole 57 collides with the guide wall 62, flows in the direction indicated by the arrow B, and returns to the oil reservoir through the oil return hole 61. By inducing the refrigerating machine oil to flow only in one direction in this manner, the refrigerating machine oil can be quickly recovered.

FIG. 8 is a diagram showing a fourth example of the direction in which the oil drain hole 57 extends. Below the upper bearing 53, there is a cylinder 52, which is provided with vanes 63 that abut the eccentrically rotating rollers and divide the compression chamber 51 into two. The cylinder 52 has an elastic body that presses the back surface of the other end in order to keep the tip of one end of the vane 63 in constant contact with the roller. The elastic body may be rubber, but may be, for example, a coil spring.

Since the vane 63 slides to maintain contact with the roller, the contact portion between the vane 63 and the cylinder 52 is rubbed, and the frictional resistance gradually increases. For this reason, it is necessary to supply refrigerating machine oil to the sliding portion in order to suppress an increase in frictional resistance. The sliding portion is continuous with the spring hole in which the coil spring is accommodated.

Therefore, an opening 64 connected to the spring hole is provided below the oil return hole 61 , and an oil discharge hole 57 is provided so that the refrigerating machine oil is discharged toward the oil return hole 61 . In the example shown in FIG. 8 , the oil discharge hole 57 extends in the radial direction of the upper bearing 53 toward one of the projections of the silencer 55 , and the oil returns to the oil return hole 61 after flowing through the upper portion of the projection. is present, and the opening 64 is provided immediately below the oil return hole 61 .

Therefore, the refrigerating machine oil that has fallen through the oil return hole 61 enters the spring hole through the opening 64 and is supplied to the sliding portion where the vane 63 and the cylinder 52 contact each other. Thereby, the frictional resistance of the sliding portion can be reduced.

In this way, by reducing the amount of refrigerating machine oil discharged to the refrigerating cycle outside the compressor together with the refrigerant, the efficiency of the refrigerating cycle can be improved, and the reliability of the compressor can be improved.

Although the compressor, the outdoor unit, and the air conditioner of the present invention have been described in detail with the above-described embodiments, the present invention is not limited to the above-described embodiments, and other embodiments and additional , change, deletion, etc., can be changed within the range that a person skilled in the art can conceive.

DESCRIPTION OF SYMBOLS 10... Indoor unit 11... Outdoor unit 12... Piping 20... Fan 21... Heat exchanger 22... Compressor 23... Control board 24... Expansion valve 30... Closed container 31... Rotary shaft 32... Primary space 33... Secondary space 34... Gas-liquid separator 35 Discharge pipe 36 Shaft hole 40 Electric motor 41 Stator 42 Rotor 43 Insulator 50 Compression mechanism 51 Compression chamber 52 Cylinder 53 Upper bearing 54 Lower bearing 55 Silencer 56 Spiral groove 57 Oil discharge hole 58 Closed portion 59 Recess 60 Refrigerant discharge hole 61 Oil return hole 62 Guide wall 63 Vane 64 Opening

Claims (7)

A compressor for compressing a fluid,
an electric motor;
a rotating shaft driven by the electric motor and having an eccentric portion;
a container disposed below the electric motor and having a compression chamber for compressing the fluid;
a rotating body provided around the eccentric portion and rotating in the compression chamber while being in contact with the inner peripheral surface of the compression chamber;
a partition member that abuts against the rotating body and partitions the compression chamber into two spaces;
an elastic body that presses one end of the partition member,
The container includes a side body to which the partition member and the elastic body are attached, and a side body which closes openings at both ends of the compression chamber and rotatably supports the rotating shaft. and two bearings for
Of the two bearings, the upper bearing on the electric motor side has a spiral groove for upwardly supplying the oil stored below the container, and a spiral groove that is continuous with the spiral groove and supplies oil through the spiral groove. and an oil drain hole for draining the oil, the oil drain hole being provided at a position on the side opposite to the rotating direction of the rotating shaft from the center of the width of the spiral groove, and A compressor extending sloping downward into the space between the electric motor and the container about an axis. 2. The compressor according to claim 1, wherein an opening of said oil drain hole facing a space between said electric motor and said container is located below a lower end of said electric motor. a muffler attached to the upper bearing for silencing the sound generated by the discharge of the fluid;
The muffler has two or more protrusions extending in a radial direction of the upper bearing and one or more recesses formed between the protrusions,
3. A compressor according to claim 1 or 2, wherein said oil drain hole extends towards one of said one or more recesses. The compressor according to any one of claims 1 to 3 , wherein the upper bearing has a guide wall on the outer peripheral portion that guides the oil discharged from the oil discharge hole to flow in a predetermined direction. The side body has an accommodation groove in which the partition member is slidably accommodated,
The upper bearing has an oil return hole formed on the accommodation groove,
The compressor according to any one of claims 1 to 3 , wherein said oil drain hole extends in a direction in which said oil return hole exists. An outdoor unit comprising the compressor according to any one of claims 1 to 5 . An air conditioner comprising the compressor according to any one of claims 1 to 5 .