KR101376872B1 - Two stage rotary compressor - Google Patents

Abstract

assignment
A rotary two-stage compressor capable of improving the followability of the refrigerant introduced into the high stage compression section and suppressing the pressure pulsation in the intermediate flow path and preventing the deterioration of the operation efficiency during low load operation is obtained.
Solution
The two stage compressor 100 which is a rotary two stage compressor of the internal high pressure type | mold has the low stage cover 19 which covers the low stage discharge port 16 and provided the low stage discharge space 20 inside. In the two-stage compressor 100, an intermediate flow path 51 in which the low stage discharge space 20 and the high stage compression chamber 35 communicate with each other is formed in the compression mechanism unit 3. In addition, the two-stage compressor 100 opens the low stage cover 19 when the load is lower than the predetermined load, and communicates the low stage discharge space 20 and the discharge pressure space 53 with each other. The mouth 23, the bypass valve 24, and the bypass valve stopper 25 are provided.

Description

Rotary two stage compressor {TWO STAGE ROTARY COMPRESSOR}

The present invention relates to a rotary two stage compressor having two compression units.

BACKGROUND ART Conventionally, a rotary two stage compressor in which two compression units (a low stage compression unit and a high stage compression unit) are provided in the compression mechanism unit and these low stage compression units and the high stage compression unit are connected in series is conventionally present. In such a rotary two stage compressor, the low stage compression unit compresses the refrigerant sucked from the heat pump cycle to a predetermined pressure (reaching pressure). This attained pressure is determined by setting the compression chamber volume of the low stage compression unit and the compression chamber volume of the high stage compression unit. The high stage compression unit further compresses the refrigerant compressed by the low stage compression unit. In the case of the internal high pressure rotary two-stage compressor, the refrigerant compressed in the high stage compression unit is discharged into the inner space of the hermetic container in the high stage compression unit, and is discharged from the inner space of the hermetic container to the heat pump cycle.

Conventionally, in an internal high pressure rotary two stage compressor, an intermediate flow path for introducing a medium pressure refrigerant compressed by a low stage compression unit into a high stage compression unit is formed so as to pass through the outside of the sealed container.

However, in the conventional rotary two-stage compressor in which the intermediate flow path is formed to pass through the outside of the sealed container, the intermediate communication passage is extremely long. As a result, there is a problem that the followability when the refrigerant in the intermediate flow path is introduced into the high stage compression section is deteriorated, resulting in pressure pulsation in the intermediate flow path, and the effect of suppressing sufficient pressure pulsation cannot be obtained.

Therefore, the conventional internal high pressure rotary two-stage compressor has been proposed in which an intermediate flow path is formed inside a sealed container.

As such a conventional rotary two-stage compressor, a discharge space constituting an intermediate flow path is formed in an intermediate partition plate that divides the low stage compression unit and the high stage compression unit, and the medium pressure refrigerant (the refrigerant discharged from the low stage compression unit) in the discharge space. Is discharged to prevent the medium pressure refrigerant from excessively flowing out to the high stage compression section (see Patent Document 1, for example).

In addition, as such a conventional rotary two-stage compressor, an intermediate flow path is provided in the compression mechanism part by shifting the phase of the suction port of the high stage compression unit from the phase of the suction port of the low stage compression unit (for example, a patent document). 2).

In addition, as such a conventional rotary two-stage compressor, an intermediate flow path is disposed between the vane groove, the low stage, and the high stage suction flow path, and the intermediate flow path is provided by passing through the compression mechanism part (for example, Patent Document 3). Reference).

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-87892 Patent Document 2: Japanese Patent Application Laid-Open No. 2007-113542 Patent Document 3: Japanese Patent Application Laid-Open No. 2010-156226

In a heat pump apparatus (heat pump cycle) using a compressor, the pressure of the refrigerant discharged by the compressor (in other words, the pressure of the refrigerant flowing into the condenser) may be low, such as when the load is small. However, the conventional rotary two-stage compressor (for example, see Patent Documents 1 to 3) in which an intermediate flow path is formed in the compression mechanism portion does not consider such a low load operation time, and therefore, the rotary two-stage compressor is used. The pressure of the refrigerant to be discharged may be higher than the desired pressure, resulting in an overcompression state. For this reason, the conventional rotary two-stage compressor in which the intermediate flow path is formed in the compression mechanism portion has a problem that the driving efficiency at the time of low load operation is lowered.

Moreover, since the rotary two stage compressor of patent document 1 forms the discharge space which discharges a medium pressure refrigerant | coolant in an intermediate partition board, it is provided in the distance between the bearings of a compression mechanism (upper and lower end of a compression mechanism, The distance between bearings for supporting the drive shaft freely in rotation increases. For this reason, the rotary two stage compressor of patent document 1 also has the problem that the curvature of the drive shaft when the load of a refrigerant | coolant acts in a compression chamber increases, and also reduces the reliability of a bearing.

Further, in the rotary two stage compressor described in Patent Document 2, since the phase of the suction port of the high stage compression section is shifted from the phase of the suction port of the low stage compression section, the use volume in the compression chamber of the high stage compression section increases, and the compression efficiency is increased. There is also a problem that causes a decrease.

In addition, in the rotary two-stage compressor described in Patent Document 3, since the installation region of the intermediate flow path is narrow, there is a problem that a restriction occurs in the flow path area of the intermediate flow path, which causes a decrease in efficiency due to pressure loss.

SUMMARY OF THE INVENTION The present invention has been made to solve at least one of the problems as described above, and can improve the followability of the refrigerant introduced into the high stage compression section to suppress pressure pulsation in the intermediate flow path, and thus the operation efficiency during low load operation. It is an object of the present invention to obtain a rotary two-stage compressor capable of preventing the deterioration.

The rotary two-stage compressor according to the present invention includes a sealed container, a compression mechanism portion disposed inside the sealed container, an electric motor disposed inside the sealed container and serving as a driving source of the compression mechanism portion, and a driving force of the electric motor. A drive shaft to be transmitted to the compression mechanism portion, wherein the compression mechanism portion is provided with a low end frame and a first through hole serving as a low end compression chamber, and the opening of one side of the first through hole is closed by the low end frame. The lower stage cylinder, the intermediate partition plate which closes the other opening part of the said 1st through hole, and the 2nd through hole used as a high stage compression chamber are formed, The said intermediate partition plate opens the one opening part of the said 2nd through hole. A high stage cylinder that is closed, a high stage frame that closes the other opening of the second through hole, and an eccentric portion of the drive shaft, A low stage rolling piston for eccentrically rotating the inside, a high stage rolling piston provided in an eccentric portion of the drive shaft and eccentrically rotating the inside of the high stage compression chamber, and the inside of the low stage compression chamber is divided into a suction space and a compression space. Low pressure vanes and high pressure vanes partitioning the inside of the high stage compression chamber into a suction space and a compression space, and the low stage frame, the low stage cylinder, the middle partition plate, the high stage cylinder, and the high stage frame are sequentially stacked, The high stage compression unit is formed, and the refrigerant sucked from the pipe connected to the low pressure suction port of the low stage compression unit is compressed in the low stage compression chamber, the refrigerant is introduced into the high stage compression chamber through an intermediate flow path and compressed again, and the high stage compression is performed. Rotary stage 2 for discharging the refrigerant compressed in the chamber into the discharge pressure space that is the inner space of the sealed container As compressors,

A low stage discharge port for discharging the refrigerant compressed in the low stage compression chamber is formed in the low stage frame, and has a low stage cover that covers the low stage discharge port and forms a low stage discharge space therein, and the intermediate flow path includes the low stage. It is formed through the frame, the low stage cylinder, and the intermediate partition plate, and the low stage discharge space and the high stage compression chamber communicate with each other. The low stage cover opens when the load is smaller than a predetermined load, and the low stage discharge space. And a bypass mechanism for communicating the discharge pressure space.

In the rotary two-stage compressor according to the present invention, since the intermediate flow path is formed inside the compression mechanism portion without being formed out of the sealed container, the intermediate flow path can be formed short. For this reason, the followability of the refrigerant | coolant introduced into a high stage compression part can be improved, and the pressure pulsation to an intermediate flow path can be suppressed.

Moreover, the rotary two stage compressor which concerns on this invention is equipped with the bypass mechanism which opens when a load is smaller than a predetermined load, and communicates the said low stage discharge space and the said discharge pressure space. Therefore, during low load operation, the refrigerant compressed by the low stage compression unit can be bypassed and discharged to the heat pump cycle without compressing the high stage compression unit. Therefore, the rotary two stage compressor which concerns on this invention can reduce the overcompression loss which arises at the time of low load operation, and can prevent the fall of the operation efficiency at the time of low load operation.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the two stage compressor which concerns on embodiment of this invention.
2 is a sectional view taken along the line AA of Fig.
3 is a cross-sectional view taken along line BB of FIG.
4 is a cross-sectional view taken along line CC of FIG. 1.
5 is a sectional view taken along line DD of FIG. 1.
6 is a cross-sectional view taken along line EE of FIG. 1.
FIG. 7 is a view comparing operation efficiency between a two stage compressor according to the present embodiment and a conventional rotary two stage compressor; FIG.

Embodiment of embodiment

Hereinafter, the structure of an example (two stage compressor 100) of the rotary two stage compressor which concerns on this invention is demonstrated.

1 is a longitudinal sectional view showing a two-stage compressor according to an embodiment of the present invention. Also, FIG. 2 shows the AA cross-sectional view of FIG. 1, FIG. 3 shows the BB cross-sectional view of FIG. 1, FIG. 4 shows the CC cross-sectional view of FIG. 1, FIG. 5 shows the DD cross-sectional view of FIG. 1, 6 shows a cross-sectional view of EE of FIG. 1. In addition, FIG. 1 is a figure which combined the longitudinal cross section cut | disconnected in several cutting position in order to make the structure of the two stage compressor 100 easy to understand. Therefore, the exact position of each structure in the planar view or the bottom view becomes a position shown in FIGS.

The two stage compressor 100 according to the present embodiment includes two compression units (the low stage compression unit 10 and the high stage compression unit 30) in the compression mechanism unit 3. The two stage compressor 100 includes an electric motor 2 (motor unit), a low stage compression unit 10, a high stage compression unit 30, a low stage cover 19, a high stage cover 39, a low stage frame 14, The high stage frame 34, the intermediate partition plate 50, the drive shaft 4, etc. are provided. In more detail, inside the sealed container 1, from the lower part to the upper part, the high stage cover 39, the high stage frame 34, the high stage compression part 30, the middle partition board 50, and the low stage compression part ( 10), the low stage frame 14, the low stage cover 19, and the electric motor 2 are arranged in this order. Moreover, the drive shaft 4 is provided along the up-down direction of the airtight container 1, and the lubricating oil storage part which stores the lubricating oil 6a in the lower part of the airtight container 1 (namely, the lower end part of the drive shaft 4). (6) is formed. This lubricating oil 6a lubricates the compression mechanism part 3, the bearing part, and the like.

The low stage compression unit 10 of the compression mechanism unit 3 is composed of a low stage cylinder 11, a low stage rolling piston 12, a low stage vane 26 (see FIG. 4), and the like. The low stage cylinder 11 has a substantially flat plate shape, and a roughly cylindrical through-hole which becomes the low stage compression chamber 15 is formed in the outline center part. In this through hole, the upper opening is closed by the low frame 14, the lower opening is blocked by the middle partition plate 50, and the low stage compression chamber 15 is formed. The low stage suction port 21 and the low stage discharge port 16 formed in the low stage frame 14 communicate with the low stage compression chamber 15. The low stage suction port 21 is connected to the suction pipe 8 via the connection pipe 9 and the suction muffler 7 provided outside the sealed container 1. That is, the low stage inlet port 21 is connected to the low pressure side of the heat pump cycle. Further, the low stage discharge port 16 is provided with a reed valve in which the plate-shaped low stage discharge valve 17 and the low stage valve presser 18 are attached by the rivets 18a (see FIG. 3). By pushing up the low stage discharge valve 17 of this reed valve and closing the low stage discharge port 16, the low stage compression chamber 15 will communicate with the low stage discharge space 20 mentioned later.

The low stage rolling piston 12 and the low stage vane 26 are provided in the low stage compression chamber 15. The low stage rolling piston 12 has a substantially cylindrical shape, and is provided in the eccentric part of the drive shaft 4. The low stage vane 26 is slidably provided in the low stage vane groove 27 formed in the low stage cylinder 11. In addition, the low stage vane 26 is biased in the direction of the drive shaft 4 by a biasing member such as a spring, and the front end thereof is free to follow the outer circumferential portion of the low stage rolling piston 12. Thereby, the low stage compression chamber 15 is partitioned into the suction space with which the low stage suction port 21 communicates, and the compression space with which the low stage discharge port 16 communicates. As can be seen from FIGS. 3 and 4, the low stage inlet 21 of the low stage compression chamber 15 communicates with the low stage compression chamber 15 near the left side of the low stage vane 26 in a plan view. have. In addition, the low stage discharge port 16 communicates with the low stage compression chamber 15 in the vicinity of the right side of the low stage vane 26 in plan view.

The high stage compression section 30 is composed of a high stage cylinder 31, a high stage rolling piston 32, a high stage vane 42 (see FIG. 5), and the like. The high stage cylinder 31 has a substantially flat plate shape, and a roughly cylindrical through-hole which becomes the high stage compression chamber 35 is formed in the outline center part. In this through hole, the upper opening is closed by the intermediate partition plate 50, the lower opening is closed by the high stage frame 34, and the high stage compression chamber 35 is formed. The high stage compression chamber 35 is formed so that the volume becomes smaller than the low stage compression chamber 15. Moreover, the high stage suction port 41 formed in the high stage cylinder 31 and the high stage discharge port 36 formed in the high stage frame 34 communicate with the high stage compression chamber 35. The high stage suction port 41 of the high stage compression unit 30 is able to communicate with the low stage discharge port 16 of the low stage compression unit 10 via the low stage discharge space 20 and the intermediate flow passage 51 described later. Further, the high stage discharge port 36 is provided with a reed valve in which the plate-shaped high stage discharge valve 37 and the high stage valve presser 38 are attached by the rivet 38a (see FIG. 6). By pushing up the high stage discharge valve 37 of this reed valve and opening the high stage discharge opening 36, the high stage compression chamber 35 will communicate with the high stage discharge space 40 mentioned later.

The high stage rolling piston 32 and the high stage vane 42 are provided in the high stage compression chamber 35. The high stage rolling piston 32 has a substantially cylindrical shape, and is provided in the eccentric part of the drive shaft 4. In this embodiment, the high stage rolling piston 32 is set to the low stage rolling piston 12 and the rough antiphase (a position which rotated approximately 180 degrees about the rotating shaft of the drive shaft 4) in planar view. . The high stage vane 42 is provided to slide freely in the high stage vane groove 43 formed in the high stage cylinder 31. The high vane 42 is biased in the direction of the drive shaft 4 by a biasing member such as a spring, and its tip is free to follow the outer circumferential portion of the high stage rolling piston 32. Thereby, the high stage compression chamber 35 is partitioned into the suction space which the high stage suction port 41 communicates with, and the compression space which the high stage discharge port 36 communicated. As can be seen from FIG. 5 and FIG. 6, the high stage suction port 41 communicates with the high stage compression chamber 35 near the left side of the high stage vane 42 when viewed in a plan view. In addition, the high stage discharge port 36 communicates with the high stage compression chamber 35 in the vicinity of the right side of the high stage vane 42 in a plan view.

3 to 6, the low stage suction port 21 of the low stage compression chamber 15 and the high stage suction port 41 of the high stage compression chamber 35 have approximately the same phase in plan view. It is. The low stage discharge port 16 and the high stage discharge port 36 are in substantially the same phase in plan view. For this reason, unlike the rotary two stage compressor shown in patent document 2, the two stage compressor 100 which concerns on this embodiment does not increase the usability of the high stage compression chamber 35, and does not reduce compression efficiency. .

The low end frame 14 is provided with the upper bearing part, and supports the substantially intermediate part of the drive shaft 4 rotatably. The low stage discharge port 16 of the low stage compression part 10 is formed in the low stage frame 14 as mentioned above. The bottom cover 19 is a cup-shaped container with an open bottom. The low stage cover 19 is provided to cover the low stage discharge port 16 from above, and forms a low stage discharge space 20 therein.

In addition, the intermediate flow path 51 also communicates with the low stage discharge space 20. The intermediate passage 51 penetrates through the low stage frame 14, the low stage cylinder 11, and the intermediate partition plate 50 in the vertical direction, and communicates with the low stage discharge space 20 and the high stage suction port 41. That is, the refrigerant flowing into the low stage discharge space 20 is sucked into the high stage compression unit 30 through the intermediate partition plate 50.

In addition, when viewed in a plan view, the intermediate flow passage 51 is the left side of the low stage vane 26 when passing through the low stage cylinder 11, and is the lower stage vane 26 (that is, the low stage vane) than the low stage suction port 21. It penetrates the position away from the groove (27). In other words, when the rotation direction of the side from which the distance from the lower stage vane 26 to the lower stage inlet port 21 is close to the center axis of the drive shaft 4 as a positive direction (arrow direction shown in FIG. 4), the middle The flow path 51 is formed downstream from the low stage suction port 21 in the forward direction.

The high stage frame 34 is provided with the lower bearing part, and supports the lower end part of the drive shaft 4 rotatably. In the high stage frame 34, the high stage discharge port 36 of the high stage compression unit 30 is formed as described above. The high stage cover 39 is a cup-shaped container with an upper opening. The high stage cover 39 is provided to cover the high stage discharge port 36 from below, and forms a high stage discharge space 40 therein.

In the high stage discharge space 40, a discharge passage 52 is formed in which the internal space of the hermetic container 1 communicates with each other. The discharge passage 52 penetrates through the high stage frame 34, the high stage cylinder 31, the middle partition plate 50, the low stage cylinder 11, and the low stage frame 14 in the vertical direction, and the high stage discharge space 40. ) And the internal space of the airtight container 1 are communicated. That is, the two-stage compressor 100 according to the present embodiment includes a discharge pressure space 53 inside the sealed container 1 (a space which becomes the pressure of the high-pressure refrigerant discharged from the high stage compression unit 30 during normal operation). This is an internal high pressure compressor. For example, a discharge tube 5 is provided at an upper portion of the sealed container 1, and the high pressure refrigerant discharged into the sealed container 1 is discharged from the discharge tube 5 to the outside. In addition, when viewed in plan, the discharge flow passage 52 penetrates the intermediate flow passage 51 at a point symmetrical position with respect to the center axis of the drive shaft 4.

The electric motor 2 becomes a drive source of the low stage compression unit 10 and the high stage compression unit 30. This electric motor 2 is provided with the stator 2a and the rotor 2b. The stator 2a has a substantially cylindrical shape, and is fixed to the inner circumferential portion of the airtight container 1. The rotor 2b has a substantially cylindrical shape and is disposed in the inner circumferential portion of the stator 2a through a predetermined gap. Moreover, the upper end part of the drive shaft 4 is inserted in the inner peripheral part of the rotor 2b.

In the second stage compressor 100 according to the present embodiment, the injector 60 is provided in the low stage cover 19. One end of the injector 60 is opened in the low stage discharge space 20, and an injection pipe 61 is connected to the other end. And the injector 60 is for injecting the refrigerant | coolant in heat pump cycles other than the two stage compressor 100 with the refrigerant discharged | emitted from the low stage compression part 10. As shown in FIG. For this reason, the connection position of the injector 60 is not limited to the low stage cover 19, but the flow path until the refrigerant discharged from the low stage compression unit 10 is sucked into the high stage compression unit 30 (low stage discharge space). ), It is possible to connect to any position.

In addition, the two-stage compressor 100 according to the present embodiment bypasses the low stage cover 19 with the low stage discharge space 20 and the discharge pressure space 53 which is an internal space of the sealed container 1. The sphere 23 is formed. The bypass port 23 is provided with a reed valve in which the plate-shaped bypass valve 24 and the bypass valve stopper 25 are attached by the rivet 29 (see FIG. 2). These are called bypass mechanisms.

In addition, in this embodiment, the positional relationship of the bypass port 23 and the intermediate | middle flow path 51 is as shown in FIG. That is, when the rotation direction of the side from which the distance from the low stage discharge port 16 to the bypass port 23 is near is made into the normal direction based on the center axis of the drive shaft 4 (the arrow direction shown in FIG. 2), the intermediate | middle The flow path 51 is formed downstream from the bypass port 23 in the forward direction.

Next, the operation of the two stage compressor 100 will be described.

When electric power is supplied, the electric motor 2 operates. The electric motor 2 and the compression mechanism part 3 are connected by the drive shaft 4, and the power generate | occur | produced in the electric motor 2 is transmitted to the compression mechanism part 3 via the drive shaft 4. Specifically, when the electric power is supplied, the rotor 2b of the electric motor 2 rotates. When the rotor 2b rotates, the drive shaft 4 subtracted from the rotor 2b also rotates. When the drive shaft 4 rotates, the low stage rolling piston 12 and the high stage rolling piston 32 into which the drive shaft 4 is inserted are eccentric in the low stage compression chamber 15 and the high stage compression chamber 35, respectively. Rotate When the low stage rolling piston 12 and the high stage rolling piston 32 are eccentrically rotated, the refrigerant is compressed in the low stage compression unit 10 and the high stage compression unit 30.

In the two stage compressor 100 thus operated, a refrigerant flows as follows.

First, a low pressure refrigerant flows into the suction muffler 7 through the suction pipe 8 from the outside. The low pressure refrigerant flowing into the suction muffler 7 is sucked into the low stage compression chamber 15 through the connecting pipe 9. The low pressure refrigerant sucked into the low stage compression chamber 15 is compressed to the intermediate pressure in the low stage compression chamber 15. When the refrigerant is compressed to an intermediate pressure, the low stage discharge valve 17 is opened by the pressure difference between the refrigerant in the low stage compression chamber 15 and the refrigerant in the low stage discharge space 20, and the refrigerant in the low stage compression chamber 15 is low stage. It discharges from the discharge port 16 to the low stage discharge space 20. Here, the intermediate pressure is a pressure determined from the ratio of the volume of the suction chamber of the low stage compression chamber 15 and the volume of the suction chamber of the high stage compression chamber 35.

The medium pressure refrigerant discharged into the low stage discharge space 20 is sucked into the high stage compression chamber 35 through the intermediate passage 51. The medium pressure refrigerant sucked into the high stage compression chamber 35 is compressed to the discharge pressure in the high stage compression chamber 35. When the refrigerant is compressed to the discharge pressure, the high stage discharge valve 37 is opened by the pressure difference between the refrigerant in the high stage compression chamber 35 and the refrigerant in the high stage discharge space 40, and the refrigerant in the high stage compression chamber 35 is high stage. It discharges from the discharge port 36 to the high stage discharge space 40. The refrigerant of the discharge pressure discharged into the high stage discharge space 40 is discharged into the discharge pressure space 53 above the low stage compression unit 10 through the discharge passage 52. And the refrigerant | coolant of the discharge pressure discharged in the discharge pressure space 53 is discharged | emitted from the discharge pipe | tube 5 to the exterior.

And when the injection operation is performed in the heat pump apparatus (heat pump cycle using the 2nd stage compressor 100) provided with the 2nd stage compressor 100, the injector 60 from the injection pipe 61 shown in FIG. ), The injected refrigerant is injected into the low stage discharge space 20. The injection refrigerant is mixed in the medium pressure refrigerant discharged from the low stage compression chamber 15 and the low stage discharge space 20 and compressed in the high stage compression unit 30.

Overcompression that results in discharge pressure (in other words, the pressure of the refrigerant flowing into the condenser) only by the compression by the low stage compression section 10, such as when the load of the heat pump device is small (hereinafter also referred to as low load operation). It may be in a state. In other words, the intermediate pressure of the refrigerant described above may be higher than the required discharge pressure. In such a case, in the two-stage compressor 100 according to the present embodiment, the bypass valve 24 is opened due to the pressure difference between the refrigerant in the low stage discharge space 20 and the refrigerant in the discharge pressure space 53. The refrigerant in the low stage discharge space 20 is discharged from the bypass port 23 to the discharge pressure space 53. In other words, in the two stage compressor 100 according to the present embodiment, the bypass valve 24 deforms when the pressure in the low stage discharge space 20 becomes larger than the pressure in the discharge pressure space 53 by a predetermined value. The bypass port 23 is opened. That is, the refrigerant discharged from the low stage compression unit 10 to the low stage discharge space 20 is bypassed and discharged to the discharge pressure space 53 without being compressed by the high stage compression unit 30.

In the overcompression state, since the discharge pressure is generated only by the compression by the low stage compression unit 10, the compression by the high stage compression unit 30 is unnecessary, and the compression is deteriorated when the high stage compression unit 30 performs compression. However, in the two stage compressor 100, when the overcompression state is achieved, the refrigerant compressed by the low stage compression unit 10 is discharged by bypassing the high stage compression unit 30. Therefore, the loss (overcompression loss) can be suppressed when an overcompression condition occurs, and the operation efficiency can be improved at the time of low load operation.

In particular, in the two stage compressor 100 according to the present embodiment, a bypass port 23 is formed in the low stage cover 19. For this reason, the refrigerant discharged from the bypass port 23 to the discharge pressure space 53 is discharged to the discharge pressure space 53 in the sealed container 1 without passing through the intermediate flow path 51. That is, the refrigerant discharged from the bypass port 23 to the discharge pressure space 53 is discharged from the bypass port 23 without the compression loss caused by passing through the intermediate flow path 51. Is discharged to. Therefore, during low load operation, overcompression loss can be effectively suppressed.

In addition, as mentioned above, the lower side of the airtight container 1 forms the lubricating oil storage part 6, and the lubricating oil 6a is enclosed. Since the lubricating oil 6a is supplied to the mechanical part of the compression mechanism part 3, the amount which immerses to the compression part (low stage compression part 10 in FIG. 1) arrange | positioned at least at the upper side is enclosed. In general rotary two-stage compressors (see Patent Documents 1 to 3), when the rotary two-stage compressor is placed vertically, the low stage compression unit is provided below the high stage compression unit. For this reason, in the rotary two stage compressor which discharges the refrigerant | coolant compressed by the low stage compression part in the low stage cover (low stage discharge space) like the rotary two stage compressor of patent document 2 and patent document 3, the low stage discharge space is low stage compression. It is provided on the lower side of the wealth. That is, the low stage cover is provided below the low stage compression unit. Therefore, the low end cover is in the state immersed in lubricating oil. In this case, when it is going to form the bypass port 23 which concerns on this embodiment in a low stage cover, lubricating oil will invade a low stage discharge space from the bypass port 23. As shown in FIG. When the refrigerant is discharged from the bypass port 23, the lubricant is rolled up to increase the outflow of the lubricant from the rotary two-stage compressor. For this reason, in the general rotary two stage compressor, the bypass port 23 according to the present embodiment cannot be formed in the low stage cover. Therefore, in the rotary two-stage compressors described in Patent Documents 2 and 3, when the rotary two-stage compressor is placed vertically, the bypass port 23 must be provided in a narrow narrow flow path connecting the low stage discharge space and the high stage compression unit. none.

However, in the two stage compressor 100 according to the present embodiment, in the vertical position, the low stage compression unit 10 is provided on the upper side of the high stage compression unit 30 as opposed to the normal one. For this reason, the low stage discharge space 20 is provided above the low stage compression part 10, and the low stage cover 19 can be made into the height which is not submerged in lubricating oil 6a. As a result, the bypass port 23 can be provided in the low stage cover 19.

In addition, since the bypass port 23 is provided in the low stage cover 19 instead of the intermediate | middle flow path 51, the two-stage compressor 100 which concerns on this embodiment has a simple structure of the bypass valve 24. FIG. Can be used as a reed valve. For this reason, the bypass valve 24 and the bypass valve presser 25 are made of the same parts as the low stage discharge valve 17 and the low stage valve presser 18 or the high stage discharge valve 37 and the high stage valve presser 38. It becomes possible. By commonizing the parts, the cost can be kept low. In addition, since the structure of the bypass valve 24 is simplified, it is also possible to reduce the cost of assembly.

Next, the characteristic of the intermediate | middle flow path 51 of the two stage compressor 100 which concerns on this embodiment is demonstrated.

As described above, the intermediate passage 51 penetrates through the low stage frame 14, the low stage cylinder 11, and the intermediate partition plate 50 in the vertical direction, and passes through the low stage discharge space 20 and the high stage suction port 41. Communicating. That is, the refrigerant compressed by the low stage compression unit 10 flows into the intermediate flow path 51 after being discharged into the low stage discharge space 20. For this reason, unlike the rotary two stage compressor of patent document 1, it is not necessary to form the discharge space of the low stage compression part 10 in the intermediate | middle partition board 50. FIG. For this reason, unlike the rotary two stage compressor of patent document 1, the two stage compressor 100 which concerns on this embodiment is the low stage frame 14 and the high stage frame 34 which also function as a bearing part of the drive shaft 4. Can reduce the distance between the two stage compressor 100 (more specifically, the low stage frame 14 and the high stage frame 34, which also function as bearings of the drive shaft 4).

Moreover, the intermediate | middle flow path 51 is located in the position away from the lower stage vane 26 (in other words, the lower vane groove 27) rather than the lower stage inlet port 21, ie, the lower stage inlet port 21 and the lower stage vane 26 (in other words, The lower surface is formed at a position other than the bottom vane groove 27. For this reason, unlike the intermediate flow path described in patent document 3, the intermediate flow path 51 which concerns on this embodiment can ensure a large flow path area, and can eliminate the factor of the efficiency fall by a pressure loss. Moreover, since the intermediate | middle flow path 51 does not interfere with the low stage suction port 21 and the low stage vane 26 (in other words, the low stage vane groove 27), the freedom degree of installation of a flow path will increase. In addition, although the intermediate | middle flow path 51 which the opening part made the outline circular shape is shown in FIG. 4 etc., as long as an opening part is formed larger than the area of the low stage discharge port 16, what kind of shape may be sufficient.

Pressure pulsation is generated in the intermediate flow path due to the amount of refrigerant flowing in and the density of density. In particular, in the rotary two stage compressor of inverter control, since a rotation speed increases and decreases, a pressure pulsation tends to occur. In the conventional rotary two-stage compressor in which the intermediate flow path is disposed outside the sealed container, since the followability of the refrigerant introduced into the high stage compression part is poor, there are several kinds of methods for dissipating the pressure pulsation in the intermediate flow path by resonance. The intermediate channel of the length of the channel shall be set. However, since the two-stage compressor 100 according to the present embodiment shortens the length of the flow path by providing the intermediate flow path 51 in the compression mechanism part 3, from the low-stage compression part 10 to the high stage compression part ( Since the followability of the refrigerant introduced into 30 can be improved and the pressure pulsation can be suppressed, the operating efficiency can be improved.

As described above, the rotational direction on the side of which the distance from the low stage discharge port 16 to the bypass port 23 is close to the center axis of the drive shaft 4 is defined as the positive direction (arrow direction shown in FIG. 2). ), The intermediate flow passage 51 is formed downstream from the bypass port 23 in the forward direction. This forward direction is the main flow direction of the refrigerant flowing from the low stage discharge port 16 to the bypass port 23. By arranging the bypass port 23 and the intermediate flow path 51 in such a positional relationship, the refrigerant in the overcompressed state discharged from the low stage compression unit 10 is bypassed (bypass port 23, bypass). By the pass valve 24 and the bypass valve stopper 25, it is discharged from the bypass port 23 into the sealed container 1 before reaching the intermediate flow path 51. For this reason, the refrigerant discharged to the discharge pressure space 53 is discharged to the discharge pressure space 53 without passing through the intermediate | middle flow path 51 more reliably, and the effect of the said bypass mechanism becomes large. On the other hand, even if the bypass mechanism (bypass mechanism provided in the low pressure cover) concerning this invention is provided in the conventional rotary two-stage compressor which arrange | positioned the intermediate flow path outside the sealed container 1, the flow path length of an intermediate flow path will be long. As a result, the refrigerant in the overcompressed state is not completely discharged from the bypass port 23, and part of the overcompressed refrigerant flows into the high stage compression unit, which causes unnecessary compression, thereby deteriorating the efficiency.

Finally, the improvement effect of the operation efficiency of the two stage compressor 100 which concerns on this embodiment is demonstrated.

7 is a diagram comparing the operation efficiency between the two stage compressor according to the present embodiment and the conventional rotary two stage compressor. The conventional rotary two-stage compressor shown in FIG. 7 is an internal high-pressure rotary two-stage compressor in which an intermediate flow path is disposed outside the sealed container, and does not include a bypass mechanism as in the present embodiment. . 7 shows the operation efficiency of the two stage compressor 100 which concerns on this embodiment with the operation efficiency of the conventional rotary two stage compressor as a reference | standard (100%).

Comparing the operating efficiency during normal operation (rated condition shown in FIG. 7), the operating efficiency of the two-stage compressor 100 according to the present embodiment is approximately 102%, which is approximately lower than that of the conventional rotary two-stage compressor. 2% operating efficiency is improving. From this result, by forming the intermediate | middle flow path 51 in the compression mechanism part 3, the followability of the refrigerant | coolant introduced into the high stage compression part 30 can be improved, and the pressure pulsation to an intermediate flow path can be suppressed, and operation efficiency is improved. It can be seen that the improvement.

When the operation efficiency at the time of low load operation (low load condition shown in FIG. 7) is compared, the operation efficiency of the two stage compressor 100 according to the present embodiment becomes approximately 101.5%, and the conventional rotary two stage compressor The driving efficiency is approximately 1/5% higher than that. From this result, the two-stage compressor 100 according to the present embodiment includes a bypass mechanism (bypass port 23, bypass valve 24, and bypass valve presser 25) on the low stage cover 19. It can be seen that when the over compression state is provided, the refrigerant compressed by the low stage compression unit 10 can be discharged by bypassing the high stage compression unit 30, thereby improving operation efficiency.

In addition, the two-stage compressor 100 in which the intermediate flow path 51 is formed in the compression mechanism unit 3 does not protrude from the airtight container 1 because the member serving as the intermediate flow path is reduced in size, ease of packaging and transport, and disassembly. Effects such as ease of use can be obtained.

1: sealed container 2: electric motor
2a: stator 2b: rotor
3: compression mechanism part 4: drive shaft
5: discharge pipe 6: lubricating oil storage unit
6a: Lubricant 7: Suction muffler
8: suction pipe 9: connector
10: low stage compression unit 11: low stage cylinder
12: low stage rolling piston 14: low stage frame
15: low stage compression chamber 16: low stage discharge port
17: low stage discharge valve 18: low stage valve presser
18a: Rivet 19: Lower Cover
20: low stage discharge space 21: low stage inlet
23: bypass port 24: bypass valve
25: bypass valve presser 26: low vane
27: Low End Vane Home 29: Rivet
30: high stage compression unit 31: high stage cylinder
32: high stage rolling piston 34: high stage frame
35 high stage compression chamber 36 high stage discharge port
37: high stage discharge valve 38: high stage valve presser
38a: Rivet 39: High Cover
40: high stage discharge space 41: high stage suction port
42: Godan Bain 43: Godan Bain Home
50: middle partition plate 51: middle euro
52: discharge passage 53: discharge pressure space
60: injector 61: injection pipe
100: two stage compressor

Claims (7)

With sealed containers,
A compression mechanism portion disposed inside the sealed container,
An electric motor disposed inside the sealed container and serving as a driving source of the compression mechanism unit;
A driving shaft for transmitting a driving force of the electric motor to the compression mechanism,
The compression mechanism unit,
Low frame,
A low stage cylinder in which a first through hole serving as a low stage compression chamber is formed, and one opening of the first through hole is closed by the low stage frame;
An intermediate partition plate for closing the other opening of the first through hole;
A high stage cylinder in which a second through hole to be a high stage compression chamber is formed, and one opening of the second through hole is closed by the intermediate partition plate;
A high end frame for closing the other opening of the second through hole;
A low stage rolling piston provided in an eccentric portion of the drive shaft and eccentrically rotating the inside of the low stage compression chamber;
A high stage rolling piston provided in an eccentric portion of the drive shaft to eccentrically rotate the inside of the high stage compression chamber;
A low pressure vane partitioning the inside of the low stage compression chamber into a suction space and a compression space;
It has a high pressure vane partitioning the inside of the high stage compression chamber into a suction space and a compression space,
The low stage frame, the low stage cylinder, the middle partition plate, the high stage cylinder, and the high stage frame are sequentially stacked to form a low stage compression unit and a high stage compression unit,
The refrigerant sucked from the pipe connected to the low pressure suction port of the low stage compression chamber of the low stage compression section is compressed in the low stage compression chamber, the refrigerant is introduced into the high stage compression chamber through an intermediate flow path and compressed again, and the high stage compression chamber is used. A rotary two-stage compressor for discharging the refrigerant compressed in the discharge pressure space, which is an inner space of the sealed container,
A low stage discharge port for discharging the compressed refrigerant in the low stage compression chamber is formed in the low stage frame,
A low stage cover covering the low stage discharge port and forming a low stage discharge space therein;
The intermediate flow passage is formed through the low stage frame, the low stage cylinder, and the intermediate partition plate, and communicates the low stage discharge space with the high stage compression chamber.
The low stage cover is provided with a bypass mechanism that opens when the load is smaller than a predetermined load, and communicates the low stage discharge space with the discharge pressure space.
And the bypass mechanism opens when the pressure in the low stage discharge space becomes higher than the pressure in the discharge pressure space by a predetermined value or more. The method of claim 1,
The compression mechanism portion, wherein the low stage compression unit is disposed above the high stage compression unit,
The bypass mechanism,
A bypass port formed in the low end cover;
And a valve which is provided to close the bypass port, deforms when a predetermined value or more is applied, and opens the bypass port. 3. The method according to claim 1 or 2,
When the rotational direction on the side near the distance from the low stage discharge port to the bypass mechanism is set to the forward direction based on the center axis of the drive shaft,
The opening part of the said intermediate | middle flow path to the said low stage discharge space is formed downstream from the said bypass mechanism in the said forward direction, The rotary two stage compressor characterized by the above-mentioned. 3. The method according to claim 1 or 2,
A rotary two stage compressor, wherein a pipe for injecting a refrigerant into the low stage discharge space is connected. 3. The method according to claim 1 or 2,
And a suction position of the refrigerant in the low stage compression chamber is substantially in phase with a suction position of the refrigerant in the high stage compression chamber. 3. The method according to claim 1 or 2,
When the direction of rotation of the side where the distance from the lower vane to the suction port is close to the center axis of the drive shaft is set as the forward direction,
The intermediate | middle flow path is formed in the said forward direction downstream from the said suction port, The rotary two-stage compressor characterized by the above-mentioned. delete

Images