JP2018188986A - Internal intermediate pressure-type two-stage compression compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal intermediate pressure-type two-stage compression compressor capable of preventing a lubricant from flowing more than it is set to a compression chamber of a high stage side.SOLUTION: A compressor has a first compression mechanism portion 30A performing low-stage compression of first stage, and a second compression mechanism portion 30B performing high-stage compression of second stage, as a compression mechanism portion 30, a lubricant supply passage 36 is formed on an intake passage 35B of the second compression mechanism portion 30B, a refrigerant gas compressed by the first compression mechanism portion 30A is discharged into a sealed container 10, the refrigerant gas is compressed by the second compression mechanism portion 30B and discharged to the outside of the sealed container 10, the lubricant is supplied from the lubricant supply passage 36 to a second compression chamber 34B of the second compression mechanism portion 30B by differential pressure between a case internal pressure of the sealed container 10 and a suction pressure in the intake passage 35B of the second compression mechanism portion 30B, and a sealed space 106 is not formed among a vane 33, a cylinder 31B and the piston 32B in swirling the piston 32B from the top dead center to a position of the intake passage 35B.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an internal / intermediate pressure two-stage compression compressor particularly suitable when carbon dioxide is used as a refrigerant.

Patent Document 1 discloses an internal medium pressure type two-stage compression compressor.
In Patent Document 1, by forming a through hole in the intermediate partition plate, the oil is pumped up from the oil sump at the bottom of the sealed container and rises in the oil supply passage in the shaft. It enters the through hole and passes through the through hole, and is supplied to the low pressure chamber side (suction side) of the high stage side cylinder.
The internal pressure (suction pressure) in the low pressure chamber of the high-stage side cylinder is lower than the pressure on the inner peripheral edge side of the intermediate partition plate due to suction pressure loss during the suction process. Due to this pressure difference, the oil is injected from the oil supply passage in the shaft through the through hole of the intermediate partition plate into the low pressure chamber in the high-stage cylinder and supplied.

JP 2004-293333 A

FIG. 4A is a plan view of the main part of the compression mechanism section on the high stage side of the internal medium pressure type two-stage compression compressor as disclosed in Patent Document 1. FIG.
FIG. 4B is a further enlarged plan view of the main part of FIG.
The compression mechanism unit 100 includes a cylinder 101, a piston 102 disposed in the cylinder 101, and a vane 103 that partitions the cylinder 101.
In FIG. 4, an oil supply passage 105 is formed in the suction passage 104 of the compression mechanism unit 100.
As shown in FIG. 4B, a closed space 106 is formed between the vane 103, the cylinder 101, and the piston 102 when the piston 102 turns from the top dead center to the position of the suction passage 104.
The closed space 106 is in a negative pressure state. When the piston 102 rotates to the position of the suction passage 104 and the closed space 106 communicates with the suction passage 104, the suction pressure in the suction passage 104 is lowered by the closed space 106.
As a result, the pressure difference between the case internal pressure and the suction pressure in the sealed container is increased, and the lubricating oil exceeding the set value flows into the compression chamber from the oil supply passage 105, and the discharge amount of the lubricating oil from the high-stage compression chamber is reduced. It will increase.
In the internal medium pressure type two-stage compression compressor, since the refrigerant is directly discharged from the high-stage compression mechanism part to the outside of the sealed container, the refrigerant is discharged into the sealed container and the lubricating oil is separated and collected in the sealed container. Compared with the internal high pressure type two-stage compression compressor, the OCR (lubricating oil circulation ratio) is high, and the compressor volumetric efficiency and the refrigeration cycle efficiency are lowered.

  Accordingly, an object of the present invention is to provide an internal / intermediate pressure two-stage compression compressor that can prevent the lubricating oil from flowing into the high-stage side compression chamber beyond the set value.

The internal medium pressure type two-stage compression compressor according to the first aspect of the present invention includes an electric motor part and a compression mechanism part in a sealed container, and the electric motor part and the compression mechanism part are connected by a shaft, and the compression mechanism part Includes a cylinder, a piston disposed in the cylinder, and a vane that partitions the cylinder, and the compression mechanism includes a first compression mechanism that performs first-stage low-stage compression, and two stages. A second compression mechanism that performs high-stage compression of the eyes, an oil supply passage is formed in the suction passage of the second compression mechanism, and the refrigerant gas compressed by the first compression mechanism is placed in the sealed container The refrigerant gas is compressed by the second compression mechanism and discharged outside the sealed container, and the difference between the case internal pressure in the sealed container and the suction pressure in the suction passage of the second compression mechanism The second compression mechanism from the oil supply passage by pressure An internal medium pressure type two-stage compression compressor for refueling the second compression chamber, when the piston is swung from top dead center to the position of the suction passage, between the vane, the cylinder and the piston. A closed space is not formed.
According to a second aspect of the present invention, there is provided the internal intermediate pressure type two-stage compression compressor according to the first aspect of the present invention, wherein the pressure communication groove is provided on a vane side wall surface located on the vane side of the suction passage. It is formed.
The internal medium pressure type two-stage compression compressor according to claim 3 of the present invention is the internal medium pressure type two stage compression compressor according to claim 2, wherein the pressure communication groove is provided with a virtual central axis parallel to the central axis of the shaft. It is characterized by being formed with a circular arc surface at the center.
According to a fourth aspect of the present invention, there is provided the internal intermediate pressure type two-stage compression compressor according to the third aspect of the present invention, wherein the arc surface extends from one end surface of the cylinder to the other end surface. It is characterized by being formed.
The internal medium pressure type two-stage compression compressor of the present invention according to claim 5 is the internal medium pressure type two stage compression compressor according to claim 3 or 4, wherein the same curvature as that of the arc surface about the virtual central axis. A curved surface is formed on an anti-vane side wall surface facing the vane side wall surface.
The internal medium pressure type two-stage compression compressor according to the present invention described in claim 6 is the internal medium pressure type two stage compression compressor according to any one of claims 1 to 5, wherein the low stage of the first compression mechanism section is provided. The exclusion volume ratio of the high-stage compression exclusion volume of the second compression mechanism section to the compression exclusion volume is 70% to 100%.
The internal medium pressure type two-stage compression compressor of the present invention according to claim 7 is the internal medium pressure type two stage compression compressor according to any one of claims 1 to 6, wherein an oil pickup is provided at a lower end of the shaft. The shaft includes an in-shaft oil supply passage through which lubricating oil sucked up by the oil pickup passes, and an intermediate partition plate is provided between the first compression mechanism portion and the first compression mechanism portion. The intermediate partition plate is formed with an intermediate partition plate oil supply passage for guiding the lubricating oil in the shaft oil supply passage to the oil supply passage.
The internal medium pressure type two-stage compression compressor of the present invention according to claim 8 is the internal medium pressure type two stage compression compressor according to any one of claims 1 to 7, wherein the refrigerant is compressed by the compression mechanism section. It is characterized by using carbon dioxide.

  According to the present invention, it is possible to prevent the lubricating oil from flowing into the second compression chamber beyond the set value, and to suppress the discharge amount of the lubricating oil from the second compression chamber.

1 is a cross-sectional view of an internal medium pressure type two-stage compression compressor according to an embodiment of the present invention. 1 is an enlarged cross-sectional view of the main part of FIG. Top view of the main part of the compression mechanism on the high stage side of the internal medium pressure type two-stage compression compressor The principal part top view of the compression mechanism part of the high stage side of the conventional internal pressure type two-stage compression compressor

  The internal medium pressure type two-stage compression compressor according to the first embodiment of the present invention does not form a closed space between the vane, the cylinder and the piston when the piston turns from the top dead center to the position of the suction passage. It is. According to the present embodiment, by eliminating the suction pressure drop caused by the closed space, it is possible to prevent the lubricating oil from flowing into the second compression chamber beyond the set value, and to suppress the discharge amount of the lubricating oil from the second compression chamber. can do.

  In the second embodiment of the present invention, in the internal medium pressure type two-stage compression compressor according to the first embodiment, a pressure communication groove is formed on a vane side wall surface located on the vane side of the suction passage. According to the present embodiment, by forming the pressure communication groove, the closed space between the vane, the cylinder and the piston, which is formed when the piston turns from the top dead center to the position of the suction passage, is eliminated. be able to.

  According to a third embodiment of the present invention, in the internal intermediate pressure type two-stage compression compressor according to the second embodiment, the pressure communication groove is formed by an arc surface centered on a virtual central axis parallel to the central axis of the shaft. It is a thing. According to the present embodiment, the pressure communication groove can be formed while suppressing the surface pressure of the vane and the vane groove.

  According to a fourth embodiment of the present invention, in the internal intermediate pressure type two-stage compression compressor according to the third embodiment, an arc surface is formed from one end surface of the cylinder to the other end surface. According to the present embodiment, the pressure communication groove can be formed by rotary cutting.

  According to a fifth embodiment of the present invention, in the internal medium pressure type two-stage compression compressor according to the third or fourth embodiment, a curved surface having the same curvature as the arc surface is opposed to the vane side wall surface with the virtual central axis as the center. It is formed on the anti-vane side wall surface. According to the present embodiment, it is possible to form the excluded volume adjusting space simultaneously with the formation of the pressure communication groove.

  According to a sixth embodiment of the present invention, in the internal intermediate pressure type two-stage compression compressor according to any one of the first to fifth embodiments, the second compression mechanism section with respect to the low-stage compression exclusion volume of the first compression mechanism section. The exclusion volume ratio of the high-stage compression exclusion volume is 70% to 100%. According to the present embodiment, an effect of reducing the amount of oil discharged from the sealed container can be expected.

  According to a seventh embodiment of the present invention, in the internal intermediate pressure type two-stage compression compressor according to any one of the first to sixth embodiments, an oil pickup is provided at the lower end of the shaft, and the oil pickup is provided at the shaft. An oil supply passage in the shaft through which the lubricating oil sucked up in the passage passes is formed, an intermediate partition plate is provided between the first compression mechanism portion and the first compression mechanism portion, and the intermediate partition plate includes a lubricant for the oil supply passage in the shaft. An oil supply passage in the intermediate partition that guides oil to the oil supply passage is formed. According to the present embodiment, it is possible to supply the lubricating oil in the hermetic container to the suction passage of the second compression mechanism portion using the pressure drop during refrigerant suction.

  The eighth embodiment of the present invention uses carbon dioxide as a refrigerant to be compressed by the compression mechanism in the internal intermediate pressure type two-stage compression compressor according to any one of the first to seventh embodiments. According to the present embodiment, even when carbon dioxide having a high refrigerant pressure and a large pressure difference between suction and discharge is used for the refrigerant, since the internal pressure of the sealed container is set to an intermediate pressure, the sealed container can be thinned and reduced in size. Since the weight can be reduced and the differential pressure per stage is reduced, the volume efficiency is improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of an internal medium pressure type two-stage compression compressor according to this embodiment, and FIG. 2 is an enlarged cross-sectional view of a main part of FIG.
The internal intermediate pressure type two-stage compression compressor according to this embodiment includes an electric motor unit 20 and a compression mechanism unit 30 in a hermetic container 10. The electric motor unit 20 and the compression mechanism unit 30 are connected by a shaft 40.
The electric motor unit 20 includes a stator 21 that is fixed to the inner surface of the sealed container 10 and a rotor 22 that rotates within the stator 21.
The internal intermediate pressure type two-stage compression compressor according to the present embodiment includes, as the compression mechanism section 30, a first compression mechanism section 30A that performs first-stage low-stage compression and a second compression mechanism section that performs second-stage high-stage compression. 30B.
The first compression mechanism 30A includes a first cylinder 31A, a first piston 32A disposed in the first cylinder 31A, and a vane (not shown) that partitions the first cylinder 31A. 32A revolves in the first cylinder 31A, and sucks and compresses the low-pressure refrigerant gas.
Similar to the first compression mechanism section 30A, the second compression mechanism section 30B includes a second cylinder 31B, a second piston 32B disposed in the second cylinder 31B, and a vane 33 that partitions the second cylinder 31B (see FIG. 3), and the second piston 32B revolves in the second cylinder 31B to suck and compress the medium-pressure refrigerant gas.

A lower bearing 51 is disposed on one surface of the first cylinder 31A, and an intermediate partition plate 52 is disposed on the other surface of the first cylinder 31A.
An intermediate partition plate 52 is disposed on one surface of the second cylinder 31B, and an upper bearing 53 is disposed on the other surface of the second cylinder 31B.
That is, the intermediate partition plate 52 partitions the first cylinder 31A and the second cylinder 31B. The intermediate partition plate 52 has an opening that is larger than the diameter of the shaft 40.
The shaft 40 includes a main shaft portion 41 to which the rotor 22 is attached and supported by the lower bearing 51, a first eccentric portion 42 to which the first piston 32A is attached, a second eccentric portion 43 to which the second piston 32B is attached, The secondary shaft portion 44 is supported by the lower bearing 51.
The first eccentric part 42 and the second eccentric part 43 are formed with a phase difference of 180 degrees, and a connecting shaft part 45 is provided between the first eccentric part 42 and the second eccentric part 43. Forming.

The first compression chamber 34A is formed between the lower bearing 51 and the intermediate partition plate 52 between the inner peripheral surface of the first cylinder 31A and the outer peripheral surface of the first piston 32A. The second compression chamber 34B is formed between the intermediate partition plate 52 and the upper bearing 53 between the inner peripheral surface of the second cylinder 31B and the outer peripheral surface of the second piston 32B.
The exclusion volume ratio of the high-stage compression exclusion volume of the second compression mechanism section 30B to the low-stage compression exclusion volume of the first compression mechanism section 30A is 70% to 100%.
An oil sump 11 is formed at the bottom of the sealed container 10, and an oil pickup 12 is provided at the lower end of the shaft 40.
Further, an in-shaft oil supply passage 46 is formed in the shaft 40 in the axial direction. The in-shaft oil supply passage 46 is formed with a communication passage 47 for supplying oil to the sliding surface of the compression mechanism 30.
The communication passage 47 is formed in the first eccentric portion 42 and the second eccentric portion 43.
An oil supply passage 36 is formed in the suction passage 35B of the second compression mechanism portion 30B.
The intermediate partition plate 52 is formed with an intermediate partition plate oil supply passage 60 that guides the lubricating oil in the shaft oil supply passage 46 to the oil supply passage 36.
The intermediate partition plate oil supply passage 60 includes a first passage 61 extending from the inner peripheral surface 52 a to the outer peripheral surface 52 b of the intermediate partition plate 52, one end opening in the first passage 61, and the other end opening in the oil supply passage 36. And two passages 62.

A first suction pipe 13A and a second suction pipe 13B are connected to the side surface of the sealed container 10, and an intermediate pressure discharge pipe 14 and a discharge pipe (not shown) are connected to the sealed container 10. The intermediate pressure discharge pipe 14 is connected to the intermediate pressure discharge port 15.
The first suction pipe 13A is connected to the suction passage 35A of the first compression mechanism section 30A, and the second suction pipe 13B is connected to the suction passage 35B of the second compression mechanism section 30B.
The suction passage 35A is connected to the first compression chamber 34A, and the suction passage 35B is connected to the second compression chamber 34B.
The intermediate pressure discharge pipe 14 is connected to an intercooler 16 that cools the medium pressure refrigerant gas, and the intercooler 16 is connected to the second suction pipe 13B.
A cup muffler 71 is provided below the lower bearing 51, and an upper cover 72 is provided above the upper bearing 53. A first silencing chamber 81 is formed between the lower bearing 51 and the cup muffler 71, and a second silencing chamber 82 is formed between the upper bearing 53 and the upper cover 72.
Medium pressure refrigerant gas compressed in the first compression chamber 34A is discharged into the first silencing chamber 81, and high pressure refrigerant gas compressed in the second compression chamber 34B is discharged into the second silencing chamber 82.

Due to the rotation of the shaft 40, the first piston 32A and the second piston 32B revolve in the first compression chamber 34A and the second compression chamber 34B.
The gas refrigerant sucked into the first compression chamber 34A from the first suction pipe 13A through the suction passage 35A by the revolving motion of the first piston 32A is compressed in the first compression chamber 34A and then into the first silencing chamber 81. Discharged.
The medium pressure refrigerant gas discharged into the first silencing chamber 81 passes through a refrigerant passage (not shown) formed in the lower bearing 51, the first cylinder 31A, the intermediate partition plate 52, the second cylinder 31B, and the upper bearing 53. And discharged into the sealed container 10.
The medium-pressure refrigerant gas discharged to the sealed container 10 is guided from the intermediate pressure discharge port 15 to the intermediate pressure discharge pipe 14, further cooled by the intercooler 16, and then guided to the second suction pipe 13 </ b> B.
The gas refrigerant sucked into the second compression chamber 34B from the second suction pipe 13B through the suction passage 35B by the revolving motion of the second piston 32B is compressed in the second compression chamber 34B and then into the second silencer chamber 82. Discharged.
The high-pressure refrigerant gas discharged into the second silencing chamber 82 is discharged out of the sealed container 10 from a discharge pipe (not shown). The high-pressure refrigerant gas discharged to the outside of the sealed container 10 is led to the first suction pipe 13A as a low-pressure refrigerant gas via a radiator, a decompressor, and an evaporator.

Further, the lubricating oil sucked up from the oil reservoir 11 by the rotation of the shaft 40 is supplied from the communication passage 47 to the compression mechanism unit 30 to lubricate the sliding surface of the compression mechanism unit 30.
Part of the lubricating oil supplied from the communication passage 47 is the pressure in the oil supply passage 46 in the shaft, that is, the case internal pressure in the sealed container 10 and the suction pressure in the suction passage 35B of the second compression mechanism portion 30B. Due to the differential pressure, the intermediate partition plate oil supply passage 60 is guided to the second compression chamber 34B of the second compression mechanism 30B through the oil supply passage 36.

FIG. 3A is a plan view of the main part of the compression mechanism section on the high stage side of the internal intermediate pressure type two-stage compression compressor according to this embodiment.
FIG. 3B is a further enlarged plan view of the main part of FIG.
A pressure communication groove 91 is formed in the vane side wall surface 35B1 located on the vane 33 side of the suction passage 35B.
The pressure communication groove 91 is formed by an arc surface centered on a virtual central axis X that is parallel to the central axis of the shaft 40. The pressure communication groove 91 is formed from one end surface of the second cylinder 31B to the other end surface.
Further, a curved surface having the same curvature as the arc surface of the pressure communication groove 91 with the virtual central axis X as the center is formed on the anti-vane side wall surface 35B2 facing the vane side wall surface 35B1, thereby eliminating the pressure communication groove 91 at the same time. A volume adjusting space 92 can be formed.
Thus, by forming the pressure communication groove 91, when the second piston 32B is swung from the top dead center to the position of the suction passage 35B, it is between the vane 33, the second cylinder 31B, and the second piston 32B. The closed space 106 (see FIG. 4) is not formed.
Then, by eliminating the suction pressure drop caused by the closed space 106 shown in FIG. 4, it is possible to prevent the lubricating oil from flowing into the second compression chamber 34B beyond the set value, and to reduce the amount of lubricating oil discharged from the second compression chamber 34B. Can be suppressed.

Further, according to the present embodiment, the pressure communication groove 91 is formed by an arc surface centered on the virtual central axis X parallel to the central axis of the shaft 40, thereby suppressing the surface pressure of the vane 33 and the vane groove. Thus, the pressure communication groove 91 can be formed.
Further, according to this embodiment, the pressure communication groove 91 can be easily formed by cutting by forming the pressure communication groove 91 from one end surface to the other end surface of the second cylinder 31B.
In addition, according to the present embodiment, the exclusion volume ratio of the high-stage compression exclusion volume of the second compression mechanism part 30B to the low-stage compression exclusion volume of the first compression mechanism part 30A is set to 70% to 100%. The effect of reducing the amount of oil discharged from the container 10 can be expected.
In addition, the internal medium pressure type two-stage compression compressor of the present embodiment can use carbon dioxide as a refrigerant. According to the present embodiment, even when carbon dioxide having a high refrigerant pressure and a large pressure difference between suction and discharge is used as the refrigerant, since the internal pressure of the sealed container 10 is set to an intermediate pressure, the sealed container 10 can be thinned. Since the size and weight can be reduced and the differential pressure per stage is reduced, volume efficiency is improved.

  Although the present invention has been described as an internal medium pressure type two-stage compression compressor, it can also be applied to a three-stage or more compression compressor.

DESCRIPTION OF SYMBOLS 10 Airtight container 11 Oil reservoir 12 Oil pick-up 13A 1st suction pipe 13B 2nd suction pipe 14 Intermediate pressure discharge pipe 15 Intermediate pressure discharge port 16 Intercooler 20 Electric motor part 21 Stator 22 Rotor 30 Compression mechanism part 30A 1st compression mechanism Part 30B second compression mechanism part 31A first cylinder 31B second cylinder 32A first piston 32B second piston 33 vane 34A first compression chamber 34B second compression chamber 35A suction passage 35B suction passage 36 oil supply passage 40 shaft 41 main shaft portion 42 First eccentric portion 43 Second eccentric portion 44 Sub shaft portion 45 Connecting shaft portion 46 In-shaft oil supply passage 47 Communication passage 51 Lower bearing 52 Intermediate partition plate 53 Upper bearing 60 Intermediate partition plate oil supply passage 61 First passage 62 First passage 62 2 passages 71 cup muffler 72 upper cover 81 first silencing chamber 82 Second silencing chamber 91 the pressure contact grooves 92 displacement volume adjusting space 106 closed space

Claims (8)

An electric motor part and a compression mechanism part are provided in the sealed container,
The electric motor part and the compression mechanism part are connected by a shaft,
The compression mechanism section includes a cylinder, a piston disposed in the cylinder, and a vane that partitions the cylinder.
As the compression mechanism section, it has a first compression mechanism section that performs first-stage low-stage compression, and a second compression mechanism section that performs second-stage high-stage compression,
Forming an oil supply passage in the suction passage of the second compression mechanism;
The refrigerant gas compressed by the first compression mechanism is discharged into the sealed container, the refrigerant gas is compressed by the second compression mechanism and discharged outside the sealed container,
An internal intermediate pressure type that supplies oil from the oil supply passage to the second compression chamber of the second compression mechanism portion by a differential pressure between the case internal pressure in the sealed container and the suction pressure in the suction passage of the second compression mechanism portion. A two-stage compressor,
An internal / intermediate pressure two-stage compression compressor, wherein a closed space is not formed between the vane, the cylinder and the piston when the piston turns from the top dead center to the position of the suction passage. 2. The internal / intermediate pressure type two-stage compression compressor according to claim 1, wherein a pressure communication groove is formed in a vane side wall surface located on the vane side of the suction passage. 3. The internal / medium pressure type two-stage compression compressor according to claim 2, wherein the pressure communication groove is formed by a circular arc surface having a virtual central axis parallel to a central axis of the shaft. The internal medium pressure type two-stage compression compressor according to claim 3, wherein the arc surface is formed from one end surface to the other end surface of the cylinder. 5. The internal intermediate pressure type two-stage according to claim 3, wherein a curved surface having the same curvature as the circular arc surface is formed on an anti-vane side wall surface facing the vane side wall surface with the virtual central axis as a center. Compression compressor. 6. The exclusion volume ratio of the high-stage compression exclusion volume of the second compression mechanism section to the low-stage compression exclusion volume of the first compression mechanism section is 70% to 100%. The internal medium pressure type two-stage compression compressor according to any one of the above. The lower end of the shaft has an oil pickup,
The shaft forms an oil supply passage in the shaft through which the lubricating oil sucked up by the oil pickup passes,
An intermediate partition plate is provided between the first compression mechanism part and the first compression mechanism part,
The intermediate partition plate is provided with an intermediate partition plate oil supply passage that guides the lubricating oil in the shaft oil supply passage to the oil supply passage. Internal medium pressure type two-stage compression compressor. The internal medium pressure type two-stage compression compressor according to any one of claims 1 to 7, wherein carbon dioxide is used as a refrigerant to be compressed by the compression mechanism section.