WO2018131111A1 - Multi-stage scroll compressor - Google Patents

Abstract

Provided is a multi-stage scroll compressor configured such that vibration and noise can be suppressed and the multi-stage scroll compressor is highly reliable. This multi-stage scroll compressor is provided with: a closed container; at least two compression mechanisms arranged within the closed container and compressing a refrigerant; and a drive mechanism for driving the compression mechanisms. The closed container has three internal spaces, which are a low-pressure space into which the refrigerant is sucked by one compression mechanism, an intermediate-pressure space into which the refrigerant sucked in from the low-pressure chamber and compressed by the one compression mechanism is discharged, and a high-pressure space into which the refrigerant sucked in from the intermediate-pressure space and compressed by the other compression mechanism is discharged. The compression mechanisms each have: a compression chamber formed by combining a stationary scroll and an orbiting scroll, which have spiral bodies protruding from base plates; and a discharge port located at the center of the spiral bodies and providing communication between the compression chamber and the internal spaces. At least one compression mechanism has a sub-port for providing communication between the compression chamber and the internal spaces, and the sub-port provides communication between the compression chamber and the internal spaces before the compression chamber is in communication with the discharge port.

Description

Multistage scroll compressor

The present invention mainly relates to a multistage scroll compressor mounted on a refrigerator, an air conditioner, or a water heater.

Conventionally, a motor using carbon dioxide as a refrigerant, a rolling piston type compression mechanism disposed at one end in a sealed housing, and a scroll type compression mechanism disposed at the other end, which drives two compression mechanisms therebetween. A multi-stage compressor having a multi-stage compression mechanism provided with an (electric motor) is known.

According to the place disclosed in Patent Document 1, in the multistage compressor, the compression mechanism on the low pressure side is constituted by a rolling piston type compression mechanism, and the compressor on the high pressure side is constituted by a scroll type compression mechanism. A scroll type compression mechanism, which is a compression mechanism on the high pressure side, forms a compression chamber by combining a fixed scroll and an orbiting scroll. The thickness of the end plate of the orbiting scroll is Worb, and the wrap height of the orbiting scroll is L. In this case, L ≧ Worb is satisfied. Thereby, deformation of each end plate of the fixed scroll and the orbiting scroll is suppressed, and the capacity of the compressor can be increased.

Japanese Patent Laid-Open No. 2008-232041 (page 8, FIG. 1)

However, in the multistage compressor disclosed in Patent Document 1, a rolling piston type compression mechanism is disposed at one end in the hermetic housing, and the low stage side rolling due to liquid return from the refrigerant circuit is performed. A suction muffler must be provided to prevent damage to the piston. If the suction muffler is attached to the side of the compressor, the balance of the compressor becomes worse, and vibration and noise increase. In particular, when the refrigerant operates at a high pressure such as carbon dioxide, the thickness of the suction muffler increases and the weight increases, which causes a problem that vibration and noise increase.

The present invention has been made in order to solve the above-described problems, and has a multistage structure having two or more scroll-type compression mechanisms in a hermetically sealed housing, suppressing an increase in vibration and noise, and maintaining performance. A scroll compressor is obtained.

A multi-stage scroll compressor according to the present invention includes a hermetic container, at least two compression mechanism parts that are disposed in the hermetic container and compress refrigerant, and a drive mechanism part that drives the compression mechanism part, The sealed container includes a low pressure space in which one of the compression mechanism portions sucks the refrigerant, an intermediate pressure space in which the refrigerant sucked from the low pressure space is compressed and discharged by the one compression mechanism portion, and the intermediate pressure space. And a high-pressure space in which the refrigerant sucked in from the other compression mechanism is compressed and discharged by the other compression mechanism, and the compression mechanism includes a fixed scroll in which a spiral body protrudes from the base plate, and A compression chamber formed by combining an orbiting scroll; and a discharge port located at a central portion of the spiral body and communicating with the compression chamber and the internal space. At least one of the compression mechanism portions includes: Above A subport that communicates the compression chamber and the internal space, and the subport communicates the compression chamber and the internal space before the compression chamber communicates with the discharge port in the compression process of the refrigerant. .

Since the multi-stage scroll compressor according to the present invention is configured as described above, even if the compression mechanism compresses the liquid refrigerant when the liquid returns from the refrigerant circuit, the refrigerant is discharged from the subport, thereby preventing excessive pressure increase. be able to. Thereby, it is possible to ensure reliability without a suction muffler, and to efficiently operate without excessively compressing the refrigerant in both the two compression mechanisms while suppressing an increase in vibration and noise generated in the multistage scroll compressor, A decrease in the performance of the multistage scroll compressor can be suppressed.

It is explanatory drawing which shows the cross section of the sealed two-stage scroll compressor which concerns on Embodiment 1 of this invention. 1 is a refrigerant circuit with a gas-liquid separator to which a sealed two-stage scroll compressor according to Embodiment 1 of the present invention is applied. It is a COP calculation result in the refrigerating cycle with a gas-liquid separator to which the hermetic two-stage scroll compressor according to Embodiment 1 of the present invention is applied. It is a Mollier diagram in the refrigerating cycle with a gas-liquid separator to which the hermetic type two-stage scroll compressor concerning Embodiment 1 of the present invention is applied. It is a figure explaining the compression process of the 1st compression chamber of the sealed two-stage scroll compressor which concerns on Embodiment 1 of this invention. It is the pressure | voltage rise curve calculation result in the 1st compression chamber when the subport is installed in the 1st compression mechanism part, and when it is not installed. It is a figure which shows the relationship between the low stage side built-in volume ratio (rho) 1 of the sealed two-stage scroll compressor which concerns on Embodiment 1 of this invention, the high stage displacement, and the low stage displacement. It is sectional drawing of the sealed two-stage scroll compressor which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the horizontal direction cross section of the 2nd eccentric part provided in the upper end part of the crankshaft of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings, devices and the like having the same reference numerals represent the same or equivalent devices, which are common throughout the entire specification. Moreover, the form of the component which appears in the whole specification is an illustration to the last, and this invention is not limited only to description in a specification. In particular, the combination of the components is not limited to the combination in each embodiment, and the components described in the other embodiments can be applied to another embodiment. Furthermore, when there is no need to distinguish or identify a plurality of similar devices that are distinguished by subscripts, the subscripts may be omitted. In the drawings, the size relationship of each component may be different from the actual one.

Embodiment 1 FIG.
FIG. 1 is an explanatory view showing a cross section of a hermetic two-stage scroll compressor 100 according to Embodiment 1 of the present invention. The hermetic two-stage scroll compressor 100 sucks a fluid such as a refrigerant, compresses it, and discharges it as a high-temperature and high-pressure state. The hermetic two-stage scroll compressor 100 includes a hermetic container 11 that is a hermetic container constituting an outer shell. Inside the sealed container 11, a first compression mechanism part 35, a second compression mechanism part 36, a drive mechanism part 37, and other components are accommodated. As shown in FIG. 1, in the sealed container 11, a first compression mechanism portion 35 is disposed below the drive mechanism portion 37, and a second compression mechanism portion 36 is disposed above the drive mechanism portion 37. A lower part of the sealed container 11 is an oil sump 21.

The first compression mechanism 35 compresses the refrigerant sucked from the suction pipe 8 communicating with the pipe outside the sealed container 11 and discharges it to the intermediate pressure space 23 in the sealed container 11. The second compression mechanism 36 compresses the fluid sucked from the intermediate pressure space 23 and discharges it to the high pressure space 24 formed above the sealed container 11. The high-temperature and high-pressure refrigerant discharged into the high-pressure space 24 is discharged from the discharge pipe 9 to a pipe outside the first compression mechanism unit 35. In order to compress the fluid, the driving mechanism unit 37 includes a first orbiting scroll 2 constituting the first compression mechanism unit 35 and a second orbiting scroll 5 constituting the second compression mechanism unit 36, respectively. And drive. That is, when the drive mechanism unit 37 drives the first or second scroll 2 and 5 via the crankshaft 7, the first compression mechanism unit 35 and the second compression mechanism unit 36 supply the refrigerant. It comes to compress.

The first compression mechanism unit 35 includes a first fixed scroll 1 and a first swing scroll 2. As shown in FIG. 1, the first orbiting scroll 2 is disposed on the upper side, and the first fixed scroll 1 is disposed on the lower side. Although it is possible to arrange the first orbiting scroll 2 on the lower side and the first fixed scroll 1 on the upper side, the first fixed scroll is fixed to the first frame 3 fixed in the sealed container 11. Thereafter, it is necessary to combine the first orbiting scroll 2 with the first fixed scroll and to add a housing for holding the first orbiting scroll 2 from the lower side. Therefore, the sealed two-stage scroll compressor 100 of the first embodiment has an advantage that the number of parts is small and the cost can be suppressed.

The first fixed scroll 1 has a first fixed base plate 1c and a first fixed spiral body 1b which is a spiral projection standing on one surface of the first fixed base plate 1c. The first swing scroll 2 includes a first swing base plate 2c and a first swing spiral body 2b which is a spiral projection standing on one surface of the first swing base plate 2c. The first fixed scroll 1 and the first orbiting scroll 2 are provided in the hermetic container 11 by meshing the first fixed spiral body 1b and the first orbiting scroll body 2b. A first compression chamber 12 is formed between the first fixed spiral body 1b and the first oscillating spiral body 2b. The first compression chamber 12 decreases in volume as it goes inward in the radial direction. In other words, a space between the spiral protrusions of the first fixed spiral body 1b and the first swing spiral body 2b is a refrigerant flow path when compressing the refrigerant. By engaging the first fixed spiral body 1b and the first swing spiral body 2b with each other, the refrigerant flow path is partitioned by the first fixed spiral body 1b and the first swing spiral body 2b at a predetermined volume, One compression chamber 12 is formed. When the first orbiting scroll 2 rotates, the first compression chamber 12 moves while decreasing in volume from the outer periphery of the first fixed scroll 1 and the first orbiting scroll 2 toward the center, Compress the refrigerant.

The first fixed scroll 1 is fixed to the first frame 3. The first frame 3 is fixed to the sealed container 11. A first discharge port 1 a is formed at the central portion of the first fixed scroll 1 to discharge a fluid that has been compressed to an intermediate pressure. A first valve 15 made of a leaf spring is provided at the outlet opening of the first discharge port 1a so as to cover the outlet opening and prevent backflow of fluid. When compressed to an intermediate pressure in the central portion of the first compression chamber 12, the first valve 15 is lifted against its elastic force, and the compressed refrigerant enters the intermediate pressure space 23 from the first discharge port 1a. Discharged. The first valve 15 is provided with a first valve presser 14 that limits the lift amount of the first valve 15. The first valve presser 14 covers the first valve 15 covering the outlet opening from the lower side, and restricts the movement of the first valve 15 lifted by the refrigerant discharged from the first discharge port to a predetermined amount. ing.

The first fixed scroll 1 is formed with a sub port 1d communicating with the intermediate pressure space 23 in addition to the first discharge port 1a. The subport 1d is installed on the way from the outer periphery to the center of the refrigerant flow path formed by the first fixed spiral body 1b of the first fixed scroll 1. The subport 1d is a hole for communicating the first compression chamber 12 and the intermediate pressure space 23 formed by dividing the refrigerant flow path. Yes. A sub-port valve 29 made of a leaf spring is provided at the outlet opening of the subport 1d so as to cover the outlet opening and prevent the reverse flow of the refrigerant. At one end of the subport valve 29, a subport valve presser 28 for limiting the lift amount of the subport valve 29 is provided. That is, when the refrigerant in the middle of compression in the first compression chamber 12 is compressed to an intermediate pressure or higher, the subport valve 29 is lifted against the elastic force, and the compressed refrigerant is introduced into the intermediate pressure space 23 from the subport 1d. Discharged.

The first orbiting scroll 2 performs an eccentric turning motion without rotating with respect to the first fixed scroll 1 by the first Oldham ring 25. A first rocking bearing portion 2 d that receives a driving force is formed at the center of the first rocking scroll 2. A first eccentric portion 7a of the crankshaft 7 described later is fitted to the first rocking bearing portion 2d of the first rocking scroll 2 with a slight gap.

The second compression mechanism unit 36 includes a second fixed scroll 4 and a second swing scroll 5. As shown in FIG. 1, the second orbiting scroll 5 is arranged on the lower side, and the second fixed scroll 4 is arranged on the upper side. The second fixed scroll 4 includes a second fixed base plate 4c, and a second fixed spiral body 4b which is a spiral projection standing on one surface of the second fixed base plate 4c. The second orbiting scroll 5 includes a second orbiting base plate 5c and a second orbiting spiral body 5b that is a spiral protrusion standing on one surface of the second orbiting base plate 5c. The second fixed scroll 4 and the second swing scroll 5 are disposed in the hermetic container 11 with the second fixed spiral body 4b and the second swing spiral body 5b meshing with each other. A second compression chamber 13 is formed between the second fixed spiral body 4b and the second oscillating spiral body 5b. The second compression chamber 13 decreases in volume as it goes inward in the radial direction. In other words, a space between the spiral protrusions of the second fixed spiral body 4b and the second swing spiral body 5b is a refrigerant flow path when compressing the refrigerant. By engaging the second fixed spiral body 4b and the second swing spiral body 5b with each other, the refrigerant flow path is partitioned by the second fixed spiral body 4b and the second swing spiral body 5b with a predetermined volume, Two compression chambers 13 are formed. When the second orbiting scroll 5 rotates, the second compression chamber 13 moves while decreasing in volume from the outer periphery of the second fixed scroll 4 and the second orbiting scroll 5 toward the center, Compress the refrigerant.

The second fixed scroll 4 is fixed to the second frame 6. The second frame 6 is fixed to the sealed container 11. A second discharge port 4 a that discharges the compressed high-pressure refrigerant is formed at the center of the second fixed scroll 4. A second valve 17 made of a leaf spring is provided at the outlet opening of the second discharge port 4a so as to cover the outlet opening and prevent the reverse flow of the refrigerant. A second valve presser 16 that restricts the lift amount of the second valve 17 is provided at one end of the second valve 17. When the fluid is compressed to a predetermined pressure in the second compression chamber 13, the second valve 17 is lifted against its elastic force, and the compressed refrigerant is discharged into the high-pressure space 24 from the second discharge port 4a. Then, it is discharged outside the hermetic two-stage scroll compressor 100 through the discharge pipe 9.

The second orbiting scroll 5 performs an eccentric turning motion without rotating with respect to the second fixed scroll 4 by the second Oldham ring 26. A second rocking bearing portion 5 d that receives a driving force is formed at the center of the second rocking scroll 5. A second eccentric portion 7b of the crankshaft 7 described later is fitted to the second rocking bearing portion 5d of the second rocking scroll 5 with a slight gap. The surface of the second rocking scroll 5 opposite to the surface on which the second rocking spiral body 5 b is formed is supported in the axial direction by a thrust bearing portion 6 b provided on the second frame 6.

The drive mechanism portion 37 is fixedly held inside the sealed container 11, is rotatably disposed on the inner peripheral surface side of the stator 20, is fixed to the crankshaft 7, and is installed in the sealed container 11. And a crankshaft 7 that is housed in a vertical direction and rotates together with the rotor 19. The stator 20 has a function of rotating the rotor 19 when energized. The stator 20 is fixedly supported on the sealed container 11 by an outer peripheral surface by shrink fitting or the like. The rotor 19 is rotationally driven when the stator 20 is energized to rotate the crankshaft 7. The rotor 19 has a permanent magnet inside, is fixed to the outer periphery of the crankshaft 7, and is held with a slight gap from the stator 20.

The crankshaft 7 is rotated with the rotation of the rotor 19 to drive the first orbiting scroll 2 and the second orbiting scroll 5 to rotate. The crankshaft 7 is rotatably supported by a bearing portion 6 a formed at the center of the second frame 6 in the upper part of the sealed container 11. Further, the crankshaft 7 is rotatably supported by a bearing portion 3 a formed at the center portion of the first frame 3 fixedly disposed on the sealed container 11 in the lower part of the sealed container 11. The lower end portion of the crankshaft 7 is provided with a first eccentric portion 7a that is fitted to the first rocking bearing portion 2d so that the first rocking scroll 2 can be rotated while being eccentric. Is provided with a second eccentric part 7b fitted to the second rocking bearing part 5d so that the second rocking scroll 5 can be rotated while being eccentric. The second frame 6 may be fixed to the inner peripheral surface of the sealed container 11 by shrink fitting or welding.

The sealed container 11 includes a suction pipe 8 for sucking the refrigerant into the sealed container 11, a discharge pipe 9 for discharging the refrigerant out of the sealed container 11, and an injection pipe 10 for guiding the refrigerant that cools the intermediate pressure space 23. It is connected.

In the sealed container 11, the first frame 3 is fixed below the drive mechanism 37 and the second frame 6 is fixed above the drive mechanism 37. The first frame 3 is fixed to the inner peripheral surface of the sealed container 11, and a through hole is formed at the center for supporting the crankshaft 7. The first frame 3 supports the crankshaft 7 rotatably by a bearing portion 3a. The bearing portion 3a is configured by, for example, a rolling bearing. The second frame 6 is fixed to the inner peripheral surface of the sealed container 11, and a through hole is formed at the center for supporting the crankshaft 7. The second frame 6 supports the second orbiting scroll 5 and supports the crankshaft 7 rotatably by a bearing portion 6a.

An oil pump 40 is disposed below the crankshaft 7. The first fixed scroll 1 is provided with a through hole so that the rotational force of the crankshaft 7 can be transmitted to the oil pump 40. The oil pump 40 is a positive displacement pump, and according to the rotation of the crankshaft 7, the refrigerating machine oil held in the oil sump 21 passes through the oil circuit 27 provided in the crankshaft 7 to the first rocking bearing portion 2 d and the bearing portion 3 a. The second rocking bearing portion 5d, the bearing portion 6a, and the thrust bearing portion 6b are supplied.

In the sealed container 11, the first Oldham ring 25 for preventing the rotation of the first orbiting scroll 2 during the eccentric orbiting movement and the rotation of the second orbiting scroll 5 during the eccentric orbiting movement are prevented. A second Oldham ring 26 is provided for this purpose. The first Oldham ring 25 is disposed between the first orbiting scroll 2 and the first frame 3 so as to prevent the rotation of the first orbiting scroll 2 and to perform a revolving motion. It has become. The second Oldham ring 26 is disposed between the second orbiting scroll 5 and the second frame 6 and functions to prevent the rotation of the second orbiting scroll 5 and to enable a revolving motion. It is like that.

Here, the operation of the hermetic two-stage scroll compressor 100 will be described. When a power supply terminal (not shown) provided in the sealed container 11 is energized, torque is generated in the stator 20 and the rotor 19 and the crankshaft 7 rotates. The first orbiting scroll 2 is rotatably fitted to the first eccentric portion 7a of the crankshaft 7, and the second orbiting scroll 5 is rotatably fitted to the second eccentric portion 7b of the crankshaft 7. A first swing scroll 2 having a spiral body (first fixed spiral body 1b, first swing spiral body 2b, second fixed spiral body 4b, second swing spiral body 5b) created in accordance with an involute curve; A plurality of first compression chambers 12 are engaged with the first fixed scroll 1, and a plurality of second compression chambers 13 are formed with the second rocking scroll 5 and the second fixed scroll 4.

The first compression chamber 12 that has taken in the gas from the suction pipe 8 reduces the volume while compressing the refrigerant while moving from the outer peripheral portion toward the center along with the eccentric orbiting motion of the first swing scroll 2. The refrigerant gas compressed in the first compression chamber 12 is discharged from the first discharge port 1 a provided in the first fixed scroll 1 to the intermediate pressure space 23 against the first valve 15. The refrigerant compressed in the first compression chamber 12 is mixed with the refrigerant that has flowed from the injection pipe 10 that connects the intermediate pressure space 23 and the piping outside the sealed container 11.

Then, the second compression chamber 13 that has taken in the refrigerant from the intermediate pressure space 23 reduces the volume while moving in the central direction from the outer peripheral portion with the eccentric orbiting motion of the second orbiting scroll 5, and compresses the refrigerant. The refrigerant gas compressed in the second compression chamber 13 is discharged from the second discharge port 4 a provided in the second fixed scroll 4 against the second valve 17 and discharged from the discharge pipe 9 to the outside of the sealed container 11. The deformation of the first valve 15 and the second valve 17 is restricted so as not to be deformed more than necessary by the first valve retainer 14 and the second valve retainer 16, respectively, thereby preventing the first valve 15 and the second valve 17 from being damaged. is doing.

FIG. 2 is a refrigerant circuit with a gas-liquid separator to which the sealed two-stage scroll compressor 100 according to Embodiment 1 of the present invention is applied. The high-temperature and high-pressure refrigerant discharged from the compressor 100 is cooled by the gas cooler 51. The refrigerant cooled by the gas cooler 51 is expanded to an intermediate pressure by the first expansion valve 52. Thereafter, the refrigerant enters the gas-liquid separator 54. The liquid refrigerant accumulated at the bottom of the gas-liquid separator 54 is expanded to a low pressure by the second expansion valve 53 and then becomes a gas refrigerant by the evaporator 55 and is sucked from the suction pipe 8 of the hermetic two-stage scroll compressor 100. . As described above, the refrigerant circuit is provided with two expansion valves and is configured by two-stage expansion, so that the refrigerating capacity can be improved more than the first-stage expansion. On the other hand, the gas refrigerant separated by the gas-liquid separator 54 and located above the gas-liquid separator 54 flows into the intermediate pressure space 23 from the injection pipe 10 of the hermetic two-stage scroll compressor 100 and enters the second compression chamber. 13 is sucked and compressed.

FIG. 3 is a COP calculation result in a refrigeration cycle with a gas-liquid separator to which the hermetic two-stage scroll compressor 100 according to Embodiment 1 of the present invention is applied. In FIG. 3, the COP calculation result when the refrigerant is carbon dioxide (R744), the high pressure is 10 MPa, and the low pressure is 1 MPa is shown with the intermediate pressure as a parameter on the horizontal axis. According to the calculation result, the COP is better when the intermediate pressure is set lower.

FIG. 4 is a Mollier diagram in a refrigeration cycle with a gas-liquid separator to which the sealed two-stage scroll compressor 100 according to Embodiment 1 of the present invention is applied. 4 is a Mollier diagram when the refrigerant is carbon dioxide (R744), the high pressure is 10 MPa, and the low pressure is 1 MPa. FIG. 4 (a) is an intermediate pressure of 2 MPa, and FIG. 4 (b) is an intermediate pressure of 3 MPa. The refrigeration cycle in the case of. As shown in FIG. 4A, the lower the intermediate pressure, the larger the enthalpy difference, the higher the refrigerating capacity and the better the COP. That is, it is desirable that the compression ratio of the first compression chamber 12 on the lower stage side is smaller than the compression ratio of the second compression chamber 13 on the higher stage side. In the case where the refrigeration cycle is constituted by carbon dioxide, the high pressure becomes supercritical due to the refrigerant characteristics, so that the refrigeration capacity becomes smaller than that of the HFC refrigerant such as R410A and the COP also decreases. Therefore, the merit of being able to improve the refrigerating capacity by configuring a two-stage expansion cycle with a gas-liquid separator is increased.

Although the COP is better when the compression ratio of the first compression chamber 12 on the lower stage side is smaller, in the case of a scroll type compression mechanism, the refrigerant taken in has a discharge side pressure in the compression chamber according to the built-in volume ratio of the compression mechanism. There are cases where the pressure is increased beyond that (overcompression). The amount of pressure increased beyond the discharge side pressure becomes extra work, and the performance of the hermetic two-stage scroll compressor 100 is reduced. Therefore, in the sealed two-stage scroll compressor 100 according to the first embodiment, the built-in volume ratio ρ2 of the second compression chamber 13 on the higher stage side than the built-in volume ratio ρ1 of the first compression chamber 12 on the lower stage side. By increasing the value, it is possible to reduce extra work in the low-stage compression mechanism and improve performance.

Here, for example, the built-in volume ratio ρ1 of the first compression chamber is equal to the compression chamber volume V _s1 (displacement amount = 2 × V _s1 ) immediately after completion of closing in FIG. It is a ratio with the compression chamber volume V _e1 immediately before communicating with the chamber, and is represented by ρ1 = V _s1 / V _e1 . Similarly, if the built-in volume ratio ρ2 of the second compression chamber is V _s2 , and the compression chamber volume V _e2 just before communicating with the innermost chamber of the second compression chamber is It is represented by ρ2 = V _s2 / V _e2 . In addition, since a refrigerant | coolant cannot be compressed when a built-in volume ratio is 1 or less, it will be set to 1 <ρ1 <ρ2.

FIG. 5 is a diagram for explaining the compression process of the first compression chamber 12 of the hermetic two-stage scroll compressor according to Embodiment 1 of the present invention. 5A to 5F show the compression process of the first compression chamber 12 every 60 °. The first compression chamber 12 moves while reducing its volume toward the center along with the orbiting motion of the first orbiting scroll 2, and compresses the refrigerant. One subport 1d is provided in each of the first compression chambers 12 that are symmetric with respect to the center of the first fixed scroll 1, and is configured so that the pressures of the first compression chambers 12 in the symmetric positions are equal. ing.

FIG. 5A shows a state where the refrigerant suction of the first compression chamber 12 formed by the first fixed scroll 1 and the first orbiting scroll 2 is completed (the closing completion angle is 0 °). The subport 1d is formed at a position that does not communicate with the low pressure space 22.
FIGS. 5B and 5C show a state in which the first orbiting scroll 2 is rotated from the state of FIG. The first compression chamber 12 gradually moves to the inside of the spiral body by the rotation of the first orbiting scroll, and the volume gradually decreases.
In FIG. 5 (d), the orbiting motion of the first orbiting scroll 2 has advanced, and the first fixed spiral body 1b and the first orbiting spiral body 2b have moved onto the subport 1d.
In FIG. 5 (e), the orbiting motion of the first orbiting scroll 2 further proceeds, the first compression chamber 12 taking in the refrigerant in (a) moves toward the center, and the subport 1 d is connected to the first compression chamber 12. Communicated with. If the pressure in the first compression chamber 12 exceeds the pressure in the intermediate pressure space 23, the refrigerant starts to be discharged from the subport 1d.
In FIG. 5 (f), the orbiting motion of the first orbiting scroll 2 further proceeds, and the first compression chamber 12 and the subport 1d continue to communicate with each other. Therefore, when the pressure in the first compression chamber 12 exceeds the pressure in the intermediate pressure space 23, the refrigerant continues to be discharged from the subport 1d. When the pressure in the first compression chamber 12 becomes the same as the pressure in the intermediate pressure space 23, the subport valve 29 is closed, and the discharge is completed.
When returning to the state of FIG. 5 (a) again, the orbiting motion of the first orbiting scroll 2 is further advanced, and the subport 1d is closed by the first orbiting scroll.
In FIG. 5B, the orbiting motion of the first orbiting scroll 2 further proceeds, and the innermost chamber with the first discharge port 1a and the first compression chamber 12 in front of it are in a state immediately before communication. Yes. When the orbiting motion of the first orbiting scroll 2 further proceeds from here, the innermost chamber communicates with the first compression chamber 12 in front of it, and when the pressure in the intermediate pressure space 23 is exceeded, from the first discharge port 1a. The refrigerant is discharged.

FIG. 6 shows the calculation results of the pressure increase curve in the first compression chamber 12 when the subport 1d is installed in the first compression mechanism 35 and when it is not installed. With the subport 1d, compared to the case without the subport 1d, the overshoot of the boosting curve is reduced and the loss is reduced. Therefore, the first compression mechanism unit 35 has the subport 1d installed in the two-stage scroll compressor 100. Performance degradation can be suppressed.

When the refrigerant from the suction pipe 8 returns in a liquid state, the first compression chamber 12 compresses the liquid and the pressure rises abnormally, but the liquid refrigerant is removed by providing the subport 1d. Abnormal pressure increase can be suppressed and damage to the first compression chamber 12 can be prevented. As a result, the hermetic two-stage scroll compressor 100 can ensure reliability without providing a suction muffler upstream of the suction pipe 8. Since there is no need to install a suction muffler, the hermetic two-stage scroll compressor 100 according to Embodiment 1 can reduce the cost. Further, when the suction muffler is attached to the side surface of the compressor, the balance of the compressor is deteriorated and vibration and noise increase. However, in the sealed two-stage scroll compressor 100 according to the first embodiment, vibration and noise are also suppressed. it can.

In the first embodiment, the subport 1d is provided in the first fixed scroll 1 of the first compression mechanism, and the first compression chamber 12 and the intermediate pressure space 23 are communicated with each other by the subport 1d. A subport may be provided on the second fixed scroll 4 of the two-compression mechanism 36. In this case, the subport is configured to communicate the second compression chamber 13 and the high-pressure space 24.

FIG. 7 is a diagram showing the relationship between the low-stage built-in volume ratio ρ1, the high-stage displacement, and the low-stage displacement of the hermetic two-stage scroll compressor 100 according to Embodiment 1 of the present invention. The point shown in the graph in FIG. 7 is a lower limit at which the first compression chamber 12 on the lower stage side is not over-compressed. It shows that it can be suppressed. The relationship between the displacement amount of the first compression mechanism (low-stage displacement amount) V1 and the displacement amount of the second compression mechanism (high-stage displacement amount) V2 is such that the second compression chamber 13 is more than the refrigerant taken in from the suction pipe 8. V2 / V1 ≦ 1 is set so as not to suck the refrigerant. The condition in which the first compression chamber 12 is not overcompressed is a region indicated by the hatched portion in FIG. 7, and the value that V2 / V1 can take increases as the built-in volume ratio ρ1 on the lower stage side increases. . The condition of ρ1 and V2 / V1 at which the first compression chamber 12 is not overcompressed is V2 / V1 ≧ 1 / ρ1. Further, the upper limit of the built-in volume ratio ρ1 is determined by the shapes of the first fixed scroll 1 and the first swing scroll 2 that can be stored in the sealed container 11. In FIG. 7, the built-in volume ratio ρ1 has an upper limit of 4.0, but is not limited to this.

In the first embodiment, the sealed two-stage scroll compressor 100 having the first compression mechanism section 35 and the second compression mechanism section 36 has been described as an example. However, the compressor further includes a multistage compression mechanism section. It may be. The hermetic two-stage scroll compressor 100 corresponds to the multi-stage scroll compressor of the present invention.

(Effect of Embodiment 1)
(1) A hermetic two-stage scroll compressor 100 according to the first embodiment includes a hermetic container 11, at least two first compression mechanism portions 35 that are arranged in the hermetic container 11 and compress refrigerant, and a second compression mechanism. Part 36, a first compression mechanism part 35, and a drive mechanism part 37 that drives the second compression mechanism part 36. The hermetic container 11 includes a low-pressure space 22 in which one of the first compression mechanisms 35 sucks refrigerant, and an intermediate pressure space 23 in which the refrigerant sucked from the low-pressure space 22 is compressed and discharged by the first compression mechanism 35. In addition, the internal pressure space 23 has three internal spaces: a high-pressure space 24 from which the refrigerant sucked from the second compression mechanism 36 is compressed and discharged. The first compression mechanism unit 35 and the second compression mechanism unit 36 are configured to connect the first fixed spiral body 1b, the first swing spiral body 2b, the second fixed spiral body 4b, and the second swing spiral body 5b to the first fixed base plate. 1c, 1st rocking base plate 2c, 2nd fixed base plate 4c, the 1st fixed scroll 1, the 2nd fixed scroll 4, the 1st rocking scroll 2, and 2nd which protruded from the 2nd rocking base plate 5c A first compression chamber 12, a second compression chamber 13, and a first fixed spiral 1b, a first swing spiral 2b, a second fixed spiral 4b, and a second swing spiral formed by combining the swing scroll 5. It has the 1st discharge port 1a and the 2nd discharge port 4a which are located in the center part of the body 5b, and connect the 1st compression chamber 12, the 2nd compression chamber 13, and internal space. The at least one first compression mechanism unit 35 includes a subport 1d that allows the first compression chamber 12 and the internal space to communicate with each other. The subport 1d allows the first compression chamber 12 and the internal space to communicate with each other before the first compression chamber 12 communicates with the first discharge port 1a in the refrigerant compression process. The first compression mechanism unit 35 corresponds to one compression mechanism unit of the present invention, and the second compression mechanism unit 36 corresponds to the other compression mechanism unit of the present invention. The first fixed spiral body 1b, the first swing spiral body 2b, the second fixed spiral body 4b, and the second swing spiral body 5b correspond to the spiral body of the present invention, and the first fixed base plate 1c, The first swing base plate 2c, the second fixed base plate 4c, and the second swing base plate 5c correspond to the base plate of the present invention. Further, the first compression chamber 12 and the second compression chamber 13 correspond to the compression chamber of the present invention.
(2) According to the hermetic two-stage scroll compressor 100 according to Embodiment 1, the subport is a refrigerant flow path extending from the outer periphery of the first fixed spiral body 1b of the first fixed scroll 1 to the first discharge port 1a. It is provided on the way.
With this configuration, in the hermetic two-stage scroll compressor 100 according to Embodiment 1, for example, when the liquid refrigerant is sucked from the suction pipe 8, the pressure in the first compression chamber 12 becomes high. However, since the refrigerant is removed from the subport 1d, the reliability is improved. Further, since it is not necessary to provide a muffler before the refrigerant is sucked into the first compression mechanism portion 35, vibration and noise generated in the hermetic two-stage scroll compressor 100 can be prevented, and the cost can be suppressed. Can do. Further, by providing a subport also in the second compression mechanism section 36, the pressure in the second compression chamber 13 is not increased beyond the discharge side pressure, and the hermetic two-stage scroll compressor 100 does extra work. There will be no increase in efficiency.

(3) According to the sealed two-stage scroll compressor 100 according to the first embodiment, the outlet opening of the subport 1d includes the subport valve 29 that prevents the refrigerant from flowing backward from the internal space to the compression chamber.
With this configuration, for example, the refrigerant discharged from the first compression chamber 12 to the intermediate pressure space 23 does not flow back to the first compression chamber 12, so that the reliability of the hermetic two-stage scroll compressor 100 is improved. Increases nature.

(4) According to the sealed two-stage scroll compressor 100 according to the first embodiment, the two compression mechanism sections compress the refrigerant sucked from the low pressure space 22 and discharge it to the intermediate pressure space 23. It comprises at least two of a part 35 and a second compression mechanism part 36 that compresses the refrigerant sucked from the intermediate pressure space 23 and discharges it to the high pressure space 24. The built-in volume ratio ρ1 of the first compression mechanism unit 35 is smaller than the built-in volume ratio ρ2 of the second compression mechanism unit 36.
With this configuration, in the hermetic two-stage scroll compressor 100 according to Embodiment 1, the second compression chamber on the higher stage side than the built-in volume ratio ρ1 of the first compression chamber 12 on the lower stage side. By increasing the built-in volume ratio ρ2 of 13, the extra work in the first compression mechanism 35 on the lower stage side can be reduced and the performance can be improved.

(5) According to the hermetic two-stage scroll compressor 100 according to the first embodiment, the subport 1d provided in the first compression mechanism section 35 is connected to the first compression chamber 12 provided in the first compression mechanism section 35. And the intermediate pressure space 23 communicate with each other.
(6) Further, according to the hermetic two-stage scroll compressor 100 according to the first embodiment, the subport provided in the second compression mechanism unit 36 is the second compression chamber provided in the second compression mechanism unit 36. 13 communicates with the high-pressure space 24.
With this configuration, the hermetic two-stage scroll compressor 100 according to Embodiment 1 can achieve the effects described in the above (1) and (2).

(7) According to the hermetic two-stage scroll compressor 100 according to the first embodiment, the first compression mechanism unit 35 is disposed below the drive mechanism unit 37, and the second compression mechanism unit 36 includes the drive mechanism unit. 37 is disposed above.
With this configuration, the hermetic two-stage scroll compressor 100 can efficiently drive the first compression mechanism section 35 on the low stage side and the second compression mechanism section 36 on the high stage side. .

(8) According to the hermetic two-stage scroll compressor 100 according to the first embodiment, the first orbiting scroll 2 provided in the first compression mechanism unit 35 is provided in the first compression mechanism unit 35. It arrange | positions above the 1 fixed scroll 1, and the 1st fixed scroll 1 is being fixed inside the airtight container.
By being configured in this way, the hermetic two-stage scroll compressor 100 can reduce the number of parts and can suppress the cost.

(9) According to the hermetic two-stage scroll compressor 100 according to the first embodiment, when the displacement amount of the first compression mechanism unit 35 is V1 and the displacement amount of the second compression mechanism unit 36 is V2, It is set to satisfy the relationship of V2 / V1 ≦ 1 / ρ1.
With this configuration, the hermetic two-stage scroll compressor 100 prevents the second compression chamber 13 from sucking in the refrigerant from the intermediate pressure space 23 more than the refrigerant taken in from the suction pipe 8. The first compression chamber 12 is not overcompressed.

Embodiment 2. FIG.
In the sealed two-stage scroll compressor 100 according to Embodiment 1, the fixed crank mechanism in which the second swing scroll 5 is rotatably attached directly to the crankshaft 7 has been described as an example. In the hermetic two-stage scroll compressor 200 according to the second embodiment, a driven crank mechanism that presses the second swing scroll 5 against the second fixed scroll 4 with centrifugal force, and a back pressure is applied to the back surface of the first swing scroll 2. The structure which employ | adopted the structure applied and improved the airtightness of the 1st compression mechanism part 35 and the 2nd compression mechanism part 36 is demonstrated.

FIG. 8 is a cross-sectional view of a hermetic two-stage scroll compressor 200 according to Embodiment 2 of the present invention. FIG. 9 is an explanatory diagram showing a horizontal cross section of the second eccentric portion 7b provided at the upper end portion of the crankshaft 7 of FIG. FIG. 9A shows the state when the compressor is stopped. Since the crankshaft 7 is not rotating, the bush 18 is centered on the second eccentric portion 7b. FIG. 9B shows a state during the operation of the compressor. When the crankshaft 7 rotates, the center of the bush 18 is shifted from the center of the second eccentric portion 7b. A flat surface portion 7ba in contact with the outer peripheral surface of the second eccentric portion 7b is provided on the inner peripheral surface of the bush 18 provided at the upper end portion of the crankshaft 7. When the crankshaft 7 rotates, the bush 18 moves in the radial direction along the flat portion, and the side surface of the second swing scroll 5b of the second swing scroll 5 is the side of the second fixed spiral 4b of the second fixed scroll 4. Pressed against the side. With this configuration, the second compression mechanism 36 is a driven crank mechanism that improves the airtightness of the second compression chamber 13. The axial gap between the second fixed scroll 4 and the second swing scroll 5 is, for example, a resin chip seal attached to the tip of the second swing spiral 5b and the tip of the second fixed spiral 4b. , Improve airtightness. By improving the airtightness as described above, the refrigerant gas is efficiently compressed, and the performance of the hermetic two-stage scroll compressor 200 is improved.

Further, by providing a back pressure chamber 30 on the back side of the first swing scroll 2b of the first swing scroll 2, the first swing scroll 2 is pressed against the first fixed scroll 1 during operation to improve airtightness. Can be made. For example, the back pressure chamber 30 communicates with the intermediate pressure space 23 and generates a force that presses the first swing scroll 2 toward the first fixed scroll 1 side.

The hermetic two-stage scroll compressor 200 according to the second embodiment employs a configuration in which the first rocking scroll 2 is pressed in the axial direction against the first compression mechanism unit 35, and the second compression mechanism unit 36 has a second configuration. Although the description has been given of the configuration in which the driven crank mechanism is employed in the two orbiting scroll 5, only one of the configurations may be employed.

(Effect of Embodiment 2)
(10) According to the hermetic two-stage scroll compressor 200 according to the second embodiment, during operation, the first orbiting scroll 2 provided in the first compression mechanism unit 35 is configured to store the refrigerant in the intermediate pressure space 23. The pressure is pressed against the first fixed scroll 1.
With this configuration, the hermetic two-stage scroll compressor 200 causes the first fixed scroll 1 to move the first orbiting scroll 2 by the pressure in the intermediate pressure space 23 in the first compression mechanism section 35 on the lower stage side. Since the airtightness of the first compression chamber 12 is improved, the efficiency as a compressor is improved.

(11) According to the hermetic two-stage scroll compressor 200 according to the second embodiment, the crankshaft 7 that transmits the rotation of the drive mechanism 37 to the first compression mechanism 35 and the second compression mechanism 36 is provided. Prepare. The second orbiting scroll 5 provided in the second compression mechanism portion 36 is driven by a driven crank mechanism provided between the crankshaft 7 and the second compression mechanism portion 36.
With this configuration, the hermetic two-stage scroll compressor 200 is configured so that the side surface of the second swinging spiral body 5b is the side surface of the second fixed spiral body 4b in the second compression mechanism portion 36 on the high stage side. Since it can press, since the airtightness of the 2nd compression chamber 13 improves, the efficiency as a compressor improves.

(12) Further, according to the hermetic two-stage scroll compressor 200 according to the second embodiment, during operation, the front end of the first swing scroll 2b of the first swing scroll 2 and the first fixed scroll 1 The first fixed base plate 1c comes into contact. The tip of the first fixed spiral body 1b of the first fixed scroll 1 and the first swing base plate 2c of the first swing scroll 2 come into contact with each other. The second orbiting scroll 5b of the second orbiting scroll 5 provided in the second compression mechanism 36 and the second fixed orbiting body 4b of the second fixed scroll 4 provided in the second compression mechanism 36 are: The sides touch each other.
With this configuration, the hermetic two-stage scroll compressor 200 can improve the airtightness of the first compression mechanism unit 35 and the second compression mechanism unit 36, and can improve the efficiency as a compressor. .

DESCRIPTION OF SYMBOLS 1 1st fixed scroll, 1a 1st discharge port, 1b 1st fixed spiral body, 1c 1st fixed base plate, 1d subport, 2 1st rocking scroll, 2b 1st rocking spiral body, 2c 1st rocking table Plate, 2d first rocking bearing, 3 first frame, 3a bearing, 4 second fixed scroll, 4a second discharge port, 4b second fixed spiral body, 4c second fixed base plate, 5 second rocking Scroll, 5b second rocking spiral body, 5c second rocking base plate, 5d second rocking bearing part, 6 second frame, 6a bearing part, 6b thrust bearing part, 7 crankshaft, 7a first eccentric part, 7b 2nd eccentric part, 8 suction pipe, 9 discharge pipe, 10 injection pipe, 11 airtight container, 12 1st compression chamber, 13 2nd compression chamber, 14 1st valve presser, 15 1st valve, 16 2nd valve presser 17 Second valve, 18 Bush, 19 Rotor, 20 Theta, 21 Oil reservoir, 22 Low pressure space, 23 Intermediate pressure space, 24 High pressure space, 25 First Oldham ring, 26 Second Oldham ring, 27 Oil circuit, 28 Subport valve presser, 29 Subport valve, 30 Back pressure chamber, 35 1st compression mechanism part, 36 2nd compression mechanism part, 37 Drive mechanism part, 40 Oil pump, 51 Gas cooler, 52 1st expansion valve, 53 2nd expansion valve, 54 Gas-liquid separator, 55 Evaporator, 100 Sealing type Two-stage scroll compressor, 200 sealed two-stage scroll compressor, V _e1 compression chamber volume, V _e2 compression chamber volume, V _s1 compression chamber volume, V _s2 compression chamber volume, ρ1 built-in volume ratio, ρ2 built-in volume ratio .

Claims (12)

A sealed container;
At least two compression mechanisms disposed in the sealed container and compressing the refrigerant;
A drive mechanism unit for driving the compression mechanism unit,
The sealed container is
A low-pressure space in which one of the compression mechanisms sucks the refrigerant;
An intermediate pressure space in which the refrigerant sucked from the low pressure space is compressed and discharged by one of the compression mechanisms;
The refrigerant sucked from the intermediate pressure space has three internal spaces: a high pressure space that is compressed and discharged by the other compression mechanism portion;
The compression mechanism is
A compression chamber formed by combining a fixed scroll and an orbiting scroll in which a spiral body protrudes from the base plate;
A discharge port located at the center of the spiral body and communicating with the compression chamber and the internal space;
At least one of the compression mechanism portions is
A subport for communicating the compression chamber and the internal space;
The subport is
A multi-stage scroll compressor, wherein the compression chamber communicates with the internal space before the compression chamber communicates with the discharge port in the refrigerant compression process. The subport is
2. The multistage scroll compressor according to claim 1, wherein the multistage scroll compressor is provided in the middle of a refrigerant flow path from an outer peripheral side of the spiral body of the fixed scroll to the discharge port. The outlet opening of the subport is
The multistage scroll compressor according to claim 1, further comprising a subport valve that prevents the refrigerant from flowing backward from the internal space to the compression chamber. The two compression mechanisms are
A first compression mechanism that compresses the refrigerant sucked from the low pressure space and discharges the refrigerant into the intermediate pressure space;
A second compression mechanism portion that compresses the refrigerant sucked from the intermediate pressure space and discharges the refrigerant to the high pressure space; and
The built-in volume ratio ρ1 of the first compression mechanism portion is:
The multi-stage scroll compressor according to any one of claims 1 to 3, wherein the multi-stage scroll compressor is smaller than a built-in volume ratio ρ2 of the second compression mechanism section. The subport provided in the first compression mechanism section is:
The multistage scroll compressor according to claim 4, wherein the first compression chamber provided in the first compression mechanism section and the intermediate pressure space communicate with each other. The subport provided in the second compression mechanism section is:
Communicating the second compression chamber provided in the second compression mechanism with the high-pressure space;
The multistage scroll compressor according to claim 4 or 5. The first compression mechanism section includes:
Arranged below the drive mechanism,
The second compression mechanism section is
The multistage scroll compressor according to any one of claims 4 to 6, which is disposed above the drive mechanism section. The first orbiting scroll provided in the first compression mechanism section is
Arranged above the first fixed scroll provided in the first compression mechanism,
The first fixed scroll is:
The multistage scroll compressor according to any one of claims 4 to 7, wherein the multistage scroll compressor is fixed inside the sealed container. While driving,
The first orbiting scroll provided in the first compression mechanism section is
The multistage scroll compressor according to claim 8, wherein the multistage scroll compressor is pressed against the first fixed scroll by the pressure of the refrigerant in the intermediate pressure space. A crankshaft that transmits the rotation of the drive mechanism to the first compression mechanism and the second compression mechanism;
The second orbiting scroll provided in the second compression mechanism section is
The multistage scroll compressor according to claim 8 or 9, wherein the multistage scroll compressor is driven by a driven crank mechanism provided between the crankshaft and the second compression mechanism. While driving,
A tip of the spiral body of the first orbiting scroll and a base plate of the first fixed scroll are in contact with each other;
A tip of the spiral body of the first fixed scroll is in contact with a base plate of the first swing scroll;
The side surfaces of the spiral body of the second orbiting scroll provided in the second compression mechanism section and the spiral body of the second fixed scroll provided in the second compression mechanism section are in contact with each other. The multistage scroll compressor according to any one of 1 to 10. When the displacement amount of the first compression mechanism portion is V1, and the displacement amount of the second compression mechanism portion is V2,
The multi-stage scroll compressor according to any one of claims 4 to 11, which is set to satisfy a relationship of V2 / V1≤1 / ρ1.

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