KR20020061798A - Rotary compressor for refrigerating cycle - Google Patents

Abstract

PURPOSE: A rotary compressor for refrigerating cycle is provided to prevent discharge of oil mixed with refrigerant through a refrigerant outlet. CONSTITUTION: A rotary compressor includes a hermetic vessel(10) storing oil in a lower part thereof; a driving device(20) stored in the hermetic vessel and having a stator(21) and a rotor(22); a compression device(40) installed on one side of the driving device and receiving power from the driving device to compress refrigerant; a refrigerant outlet(12) installed on the other side of the driving device to guide refrigerant compressed by the compression device to a condenser; and a bypass pipe bypassing part of refrigerant compressed by the compression device so as to reduce flow rate of refrigerant passing a passage among the stator, the rotor and the hermetic vessel.

Description

Rotary compressors for refrigeration cycles {Rotary compressor for refrigerating cycle}

The present invention relates to a rotary compressor for a refrigerating cycle, and relates to a rotary compressor for a refrigerating cycle in which lubrication of the driving unit is performed by oil.

In general, a rotary compressor is a device that compresses and discharges a refrigerant at high temperature and high pressure in a refrigeration cycle in which a compression, condensation, expansion, and evaporation process is performed through a refrigerant, and is used for an air conditioner and a refrigerator.

Conventional rotary compressors having such a function are provided with a sealed container constituting an outer body, a driving device built into the sealed container to generate power, and a compression device for sucking and discharging the refrigerant by receiving power from the driving device.

In the sealed container, oil is stored to lubricate each driving unit in the lower part, and a refrigerant inlet pipe and a refrigerant discharge pipe are provided to guide the suction / discharge of the refrigerant. The refrigerant inlet pipe is provided under the side of the sealed container so as to be adjacent to the compression device, and the refrigerant discharge pipe is provided directly above the sealed container to facilitate the refrigerant discharge.

The driving apparatus includes a rotating shaft in which an eccentric part is integrally formed, a rotor into which the upper end of the rotating shaft is press-fitted, and a stator for forming a magnetic field when power is applied to rotate the rotor at high speed. In addition, the lower end of the rotation shaft is accommodated in the oil, and pumps the oil at high speed rotation to supply to each drive unit.

Compressor is a cylinder having both sides open to form a compression chamber therein, a roller coupled to the eccentric portion of the rotating shaft to rotate and rotate in the compression chamber, and arranged above and below the cylinder respectively to form a compression chamber It consists of an upper bearing, a lower bearing, etc. which rotatably support a rotating shaft.

In addition, the cylinder is provided with a vane continuously in contact with the outer circumference of the roller, and a refrigerant suction port to which the refrigerant inlet pipe is connected. In the upper bearing, a discharge port is processed to discharge the refrigerant compressed in the compression chamber.

As the conventional rotary compressor configured as described above, as the power is applied, the rotating shaft rotates at a high speed together with the rotor of the driving device, and the eccentric portion and the roller perform the eccentric rotation and the rotating motion in the compression chamber of the cylinder.

Accordingly, the refrigerant is compressed into the compression chamber through the refrigerant inlet pipe and the refrigerant inlet, and when a predetermined pressure is reached, the discharge valve is opened and discharged into the sealed container through the discharge port. Subsequently, the refrigerant rises above the sealed container, and the discharged refrigerant flows out of the sealed container through the refrigerant discharge pipe and is supplied to the refrigeration cycle again. Subsequently, the refrigerant rises above the sealed container, exits through the refrigerant discharge pipe and is sent to the refrigeration cycle. At this time, the oil is also pumped during the rotation of the rotary shaft to lubricate each drive unit.

However, a part of the pumped oil is introduced into the compression chamber, which is compressed together with the refrigerant and is discharged while flying into the sealed container. The oil mixed in the refrigerant continues to the upper portion of the sealed container through the flow path between the stator, the rotor, and the sealed container, and then flows out through the refrigerant discharge pipe.

By repeating this phenomenon, the oil in the sealed container gradually escapes to other refrigeration cycle components such as a condenser and an evaporator, so that in the conventional rotary compressor, the oil in the sealed container becomes insufficient during long-term operation.

As a result, the oil supply is not smoothly supplied to each drive unit, so the frictional resistance is increased, and the compression compressor and the reliability of the product are deteriorated because the rotary compressor cannot be driven stably, and the efficiency of the entire refrigeration cycle by the oil introduced into the refrigeration cycle together with the refrigerant Falls too.

Therefore, in the related art, there is a case in which an oil separator for separating and returning oil from the refrigerant that has passed through the rotary compressor is separately installed. However, there is a problem that the configuration of the refrigeration cycle is difficult and the manufacturing cost is increased.

In addition, if the oil separator is installed in the middle of the refrigerant pipe, there is a problem that the vibration is amplified by the oil separator when the vibration occurs, there is a possibility that noise, etc. occur.

The present invention is to solve this problem, it is an object of the present invention to provide a rotary compressor that can effectively prevent the oil mixed in the refrigerant to escape through the refrigerant discharge pipe without installing an oil separator.

1 is a side cross-sectional view showing the overall structure of a rotary compressor for a refrigeration cycle according to the present invention.

FIG. 2 is a cross-sectional view taken along line II-II 'of FIG. 1.

3 is a cross-sectional view showing another embodiment of the present invention.

Figure 4 is a cross-sectional view showing another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: airtight container 11: oil

12: refrigerant discharge pipe 20: drive device

21: stator 22: rotor

30: Euro 40: Compressor

50a: upper bearing 50b: lower bearing

60: discharge valve 70: bypass pipe

Rotary compressor for a refrigeration cycle according to the present invention for achieving this object,

An airtight container with oil stored underneath

A driving device accommodated in the sealed container and having a stator and a rotor;

A compression device installed at one side of the driving device and receiving power from the driving device to compress the refrigerant;

A refrigerant discharge pipe installed at the other side of the driving device to guide the refrigerant compressed by the compression device to the condenser;

A bypass pipe for bypassing a portion of the refrigerant compressed by the compression device is provided to reduce the flow rate of the refrigerant passing through the flow path between the stator, the rotor and the hermetically sealed container.

In addition, both ends of the bypass pipe is installed in the sealed container, one end is installed between the drive device and the compression device and the other end is installed between the drive device and the refrigerant discharge pipe.

In addition, one end of the bypass pipe is installed between the driving device and the compression device of the sealed container and the other end is installed in the refrigerant discharge pipe.

In addition, the bypass pipe,

A connecting pipe installed on the compression device side so that oil and refrigerant flow;

Is connected to the rotary compressor by the connecting tube, provided with another compressor for discharging the refrigerant of a relatively low pressure compared to the rotary compressor,

A portion of the refrigerant compressed by the compression device is bypassed through the connecting pipe and the other compressor.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

The rotary compressor for a refrigeration cycle according to the present invention, as shown in FIG. 1, is hermetically sealed and includes a sealed container 10 in which an oil 11 is stored at the bottom, and is built in an upper space of the sealed container 10 and is a power source. It is provided with a drive device 20 for receiving the drive to generate a rotational force, and a compression device 40 for receiving, compressing and ejecting the refrigerant by receiving the rotational force generated by the drive device 20.

The driving device 20 includes a stator 21 that forms a magnetic field by applying power, a rotor 22 rotatably installed on the stator 21, and an upper end of which is pressed into the rotor 22, and is fixed to the lower end portion. The rotating shaft 23 with the core part 24 is provided.

Therefore, while the rotor 22 and the rotation shaft 23 are integrally rotated, the eccentric portion 24 is eccentrically rotated. In addition, a hollow portion 23a is provided in the axial direction inside the rotating shaft 23, and an oil paddle 25 for pumping the lower portion of the rotating shaft 23 accommodated in the oil 11 is mounted.

Therefore, the refrigerant is compressed and discharged by the rotation of the rotary shaft 23, and the oil 11 accumulated in the sealed container 10 is pumped. Reference numerals "26a" and 26b "are discharge holes for ejecting the pumped oil 11 to each drive part side.

In addition, the compression device 40 operating by the rotational force of the driving device 20 has a compression chamber 41a formed therein, and a cylinder 41 having a refrigerant suction port 41b formed therein so as to communicate with the compression chamber 41a. And the rollers 42 coupled to the eccentric 24 to rotate and rotate, respectively, and are installed at upper and lower portions of the cylinder 41 to seal the compression chamber 41a and to rotate the rotation shaft 23. And upper and lower bearings 50a and 50b that possibly support them.

In the cylinder 41, a vane (not shown) for dividing the compression chamber 41a into the suction chamber and the discharge chamber by the front end continuously in contact with the outer circumference of the roller 42 is disposed to be able to move forward and backward, and the refrigerant suction opening 41b around the vane. In the part facing the side, a half moon groove 41c for guiding the refrigerant discharge and a resonator (not shown) for reducing the discharge noise are provided.

The lower bearing 50b is mounted under the cylinder 41 to seal the lower portion of the compression chamber 41a and to rotatably support the lower end of the rotation shaft 23. On the other hand, the upper bearing 50a is mounted on the cylinder 41 together with the lower bearing 50b to seal the upper portion of the compression chamber 41a to support the rotation shaft 23.

In addition, a discharge port 51 perforated in communication with the compression chamber 41a and a discharge valve 60 for selectively opening and closing the discharge port 51 are provided at one side of the upper bearing 50a corresponding to the half moon groove 41c. Is installed.

On the other hand, the sealed container 10 forms the appearance of the rotary compressor, the refrigerant inlet pipe 13 and the refrigerant discharge pipe 12 for guiding the refrigerant flow in and out is directly connected. The refrigerant inlet pipe 13 is coupled to the lower side of the sealed container 10 so that one end is in communication with the refrigerant inlet 41b, and the other end thereof is coupled to the accumulator 14 to prevent the liquid refrigerant from entering.

The refrigerant discharge pipe 12 is installed on the upper surface of the sealed container 10 so that the refrigerant is easily discharged, and the tip is disposed so as to be adjacent to the driving device 20 through the top of the sealed container 10.

When power is applied to the rotary compressor configured as described above, the rotor 22 rotates in the stator 21, and accordingly, the rotating shaft 23 rotating together with the rotor 22 rotates and pumps oil 11. Each drive part is lubricated.

That is, the oil 11 pumped into the hollow portion 23a through the oil paddle 25 is between the roller 42 and the eccentric portion 24 and the rotary shaft 23 through the respective discharge holes 26a and 26b. It is supplied between and the upper bearing 50a, whereby each drive unit operates smoothly.

As described above, a part of the oil 11 pumped by the high speed rotation of the rotary shaft 23 is mixed into the refrigerant and moves together with the refrigerant toward the refrigerant discharge pipe 12 provided on the upper side of the rotary compressor.

The oil 11 mixed in the refrigerant rises upward through the flow path 30 provided between the rotor 22 and the stator 21 and adheres to the surfaces of the rotor 22 and the stator 21.

The oil 11 adhered as described above receives a force acting downward by gravity and a force acting upward by the refrigerant passing through the flow path 30.

Of these two forces, the force acting upward by the refrigerant is a force proportional to the refrigerant flow rate (u). When the flow rate increases more than a certain amount and becomes greater than the force acting downward by its own weight, the oil 11 is moved upward. Pushed up to discharge the refrigerant to the discharge pipe (12).

Therefore, in order to prevent the discharge of the refrigerant, it is preferable to maintain the refrigerant flow rate u below a certain level.

Refrigerant flow rate (u) by the compressor can be calculated through the following equation (1).

[Equation 1]

In Equation 1, the cooling capacity of the rotary compressor, the high-pressure gas phase refrigerant density, and the low-evaporation latent heat are values determined accordingly when the rotary compressor and the refrigerant are selected, so the refrigerant flow rate u is inversely proportional to the cross-sectional area of the cross section through which the refrigerant flows. It can be seen that the refrigerant flow rate (u) is reduced by increasing the cross-sectional area of the cross section through which the refrigerant flows.

Here, the coefficient 0.8 is a value for calculating the amount of refrigerant used for actual refrigeration. In general, since the dryness of the refrigerant in the refrigeration cycle varies from approximately 0.2 to 1.0, it can be seen that about 80% of the total refrigerant is used for actual refrigeration. have.

Therefore, the rotary compressor according to the present invention is provided with a bypass tube 70 to increase the cross-sectional area of the cross section through which the refrigerant flows.

One end of the bypass tube 70 communicates with the lower end of the sealed container 10 and the other end communicates with the upper end of the sealed container 10 so that the upper and lower portions of the sealed container 10 can be directly communicated without passing through the flow path. Thus, the speed of the coolant can be reduced by increasing the cross-sectional area of the cross section through which the coolant flows.

In the rotary compressor provided with the bypass pipe 70, the cross-sectional area A of the cross section through which the refrigerant flows can be represented by the sum of the flow path cross-sectional area A ₁ and the bypass pipe cross-sectional area A ₂ . In summary, the cross-sectional area of the pass pipe 70 is expressed as shown in Equation 2 below.

[Equation 2]

By substituting the critical refrigerant flow rate u _{crt into the} refrigerant flow rate u in Equation 2, the minimum cross-sectional area of the bypass tube 70 can be obtained.

Here, the critical refrigerant flow rate u _crt represents the flow rate of the refrigerant in the case where there is no flow of the oil 11 because the gravity acting on the oil 11 and the force transmitted by the refrigerant coincide.

Critical refrigerant flow rate (u _crt ) is a value that is influenced by various factors such as the capacity of the compressor, the width and shape of the flow path 30, the physical properties of the refrigerant, and the compression performance of the compressor. It has a value less than sec.

Therefore, when the refrigerant flow rate u is faster than the critical refrigerant flow rate u _crt , the cross-sectional area A ₂ of the bypass pipe 70 is widened so that the refrigerant flow rate u falls below the critical refrigerant flow rate u _crt . When the oil is dropped, the oil 11 flows downward by gravity to reduce the oil 11 discharged through the refrigerant discharge pipe 12.

In this embodiment, both ends of the bypass tube 70 are both installed in the hermetically sealed container 10, but as shown in FIG. 3, one end of the bypass tube 70 is disposed below the hermetic container 10. The other end may be installed in the refrigerant discharge pipe 12.

In addition, Figure 4 shows another embodiment of the present invention, as shown by connecting the compressor Y, which is relatively low pressure compared to the rotary compressor X through the first connector 71 and the second connector 72 By allowing the refrigerant compressed by the rotary compressor X to bypass the low pressure compressor Y, allowing the compressor Y to act as a bypass tube, thereby reducing the refrigerant flow rate u passing through the flow path 30 of the rotary compressor X. Configuration is also possible.

Here, the first connecting pipe (71) is installed at the bottom of the two sealed containers so that the oil and refrigerant of the two rotary compressors X, Y can communicate, the second connecting pipe (72) is the refrigerant of the two rotary compressors X, Y It is installed on top of two sealed containers so that they can communicate.

Next will be described the operation and effect of the rotary compressor according to the present invention configured as described above.

First, when power is applied to the rotary compressor according to the present invention, the rotor 22 and the rotating shaft 23 rotates at high speed integrally by interacting with the stator 21, the roller with the eccentric portion 24 is eccentrically rotated 42 eccentrically rotates and rotates in the compression chamber 41a.

Therefore, the coolant flows into the compression chamber 41a through the accumulator 14 → the coolant inlet pipe 13 → the coolant suction port 41b, and when the predetermined pressure is reached, the discharge valve 60 is opened so that the coolant groove 41c and The liquid is discharged into the sealed container 10 through the discharge port 51.

At this time, while the rotating shaft 23 rotating together with the rotor 22 rotates, the oil 11 accumulated in the lower portion is pulled upward and transferred to the driving unit through the discharge holes 26a and 26b. Some of the oil 11 is incorporated into the refrigerant.

The refrigerant is moved to the refrigerant discharge pipe 12 provided on the upper side through the flow path 30 between the rotor 22 and the stator 21, the sealed container 10, and the bypass pipe 70 by the pressure. In this case, the oil 11 mixed in the refrigerant passes through the flow path 30 and adheres to the surfaces of the rotor 22 and the stator 21 and the inner surface of the bypass pipe 70.

Since the flow rate of the refrigerant is set lower than the critical refrigerant flow rate u _crt due to the installation of the bypass pipe 70, the oil 11 adhered to the flow path 30 and the bypass pipe 70 is lowered by its own weight. Flowing down to join the oil (11) collected in the lower side of the sealed container 10 is used for lubrication again.

Therefore, since the oil 11 may be prevented from being discharged into the refrigerant discharge pipe 12, there is no need to install an oil separator separately.

On the other hand, the compression performance of the rotary compressor can be increased by increasing the number of revolutions, when only the number of revolutions increases the flow rate passing through the flow path 30 between the stator 21 and the rotor and the sealed container 10 and proportional thereto Since the amount of oil discharge also increases, it has been limited to increase the compression performance more than a certain amount.

However, the rotary compressor for a refrigerating cycle according to the present invention increases the number of revolutions of the rotary compressor to increase the compression performance, by installing a bypass pipe 70 correspondingly, to increase the cross-sectional area through which the refrigerant flows through the flow path 30 Since the coolant flow rate u drops below a predetermined level, the discharge of the oil 11 is prevented.

As detailed above,

The rotary compressor according to the present invention includes a bypass pipe, and the oil adhered to the flow path may flow downward by maintaining a flow rate of the refrigerant passing through the flow path between the stator, the rotor, and the sealed container in the rotary compressor to a predetermined level or less. It is possible to prevent the oil from being discharged through the refrigerant discharge pipe.

Therefore, there is an effect that there is no need to install an oil separator.

In addition, even if the rotational speed is increased to improve the compression performance of the rotary compressor, the flow rate of the refrigerant passing through the flow path can be controlled by increasing the cross-sectional area of the bypass pipe.

Therefore, the increase in the oil discharge amount due to the improvement of the compression performance of the rotary compressor is prevented, there is an effect that it is possible to have a higher compression performance of the rotary compressor of a certain capacity.

Claims (4)

An airtight container with oil stored underneath A driving device accommodated in the sealed container and having a stator and a rotor; A compression device installed at one side of the driving device and receiving power from the driving device to compress the refrigerant; A refrigerant discharge pipe installed at the other side of the driving device to guide the refrigerant compressed by the compression device to the condenser; And a bypass pipe for bypassing a part of the refrigerant compressed by the compression device to reduce the flow rate of the refrigerant passing through the flow path between the stator, the rotor and the hermetically sealed container. compressor. The method of claim 1, Both ends of the bypass pipe is installed in the sealed container, one end is installed between the drive device and the compression device and the other end is installed between the drive device and the refrigerant discharge pipe. compressor. The method of claim 1, One end of the bypass pipe is installed between the driving device and the compression device of the hermetic container, and the other end is installed in the refrigerant discharge pipe. The method of claim 1, The bypass pipe, A connecting pipe installed on the compression device side so that oil and refrigerant flow; Is connected to the rotary compressor by the connecting tube, provided with another compressor for discharging the refrigerant of a relatively low pressure compared to the rotary compressor, And a portion of the refrigerant compressed by the compression device bypasses the connection pipe and the other compressor.