JP2002317784A - Rotary two-stage compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always secure the lubricating oil in a middle-pressure space provided in a back surface of a low-stage vane of a rotary two-stage compressor having a sealed container filled with the discharging pressure gas. SOLUTION: A lead-in opening part 34 for supplying the oil with a pressure difference from a high-pressure oil reservoir 32 to a low-stage vane back surface chamber 33 under the medium pressure condition is arranged at a position higher than a flow-out port 89 for flowing the oil from the low-stage vane back surface chamber 33. With this structure, the lubricating oil is always secured in the low-stage vane back surface chamber 33 to improve the durability of a low-stage vane sliding part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refueling means for a rotary type two-stage compressor.

[0002]

2. Description of the Related Art Starting from recent global environmental protection problems,
Research and development of heat pump systems using natural refrigerants, particularly carbon dioxide (CO ₂ ) refrigerants, in place of CFC refrigerants that have been continuously used in the past have been actively conducted in various fields.

However, in a conventional refrigeration cycle using a chlorofluorocarbon refrigerant, the high pressure side is 3 MPa or less, whereas in a refrigeration cycle using a carbon dioxide (CO ₂ ) refrigerant, the low pressure side is 2.5 to 5 MPa and the high pressure side is 3 MPa. 12-15 on the side
Since the pressure difference reaches as high as MPa, there is a concern that excessive gas leakage loss during compression in the compressor cylinder may occur.

For these reasons, carbon dioxide (C
As a compressor using an O ₂ ) refrigerant, a conventional multistage compressor has been studied for improvement.

[0005] In particular, as a compressor mounted on a home heat pump system, a rolling piston type rotary two-stage compressor has attracted attention from the viewpoints of productivity, durability and miniaturization.

FIG. 5 is a connection diagram of a rolling piston type rotary two-stage compressor and a refrigeration cycle piping system proposed by the inventor in Japanese Patent Application Laid-Open No. 4-18787, FIG. 6 is a longitudinal sectional view of the compressor, and FIG. Shows a partial longitudinal sectional view of the compressor.

In FIG. 5 to FIG. 7, an electric motor 5, a low-stage compression element 1007 and a high-stage compression element 1
The high-stage compression mechanism 1004 accommodates a two-stage compression mechanism, and the lubricating oil 35 on which the discharge pressure acts acts on the side opposite to the high-stage vane 1039 of the rolling piston compression mechanism of the high-stage compression element 1004, and the high-stage compression mechanism is operated. The tip of the vane 1039 is pressed against the high-stage piston 1009b. On the other hand, on the side of the low-stage compression element 1007 opposite to the cylinder of the low-stage vane 1038 of the rolling piston compression mechanism, the lubricating oil in the oil reservoir 1035 is interposed via an oil supply passage 1061 having a throttle passage 1061 a provided in the middle plate 36. After the pressure has been reduced, the lubricating oil introduced into the low-stage vane rear chamber 1044 acts. With this urging force, the tip of the low-stage vane 1038 is pressed by the low-stage piston 1007b, and the inside of the cylinder is divided into a suction chamber and a compression chamber.

The lubricating oil supplied to the low-stage vane rear chamber 1044 lubricates the sliding surface of the low-stage vane 1038, while flowing into the low-stage discharge chamber 1045, and then flows through the communication passage 1055 together with the discharged refrigerant gas. Via high-stage compression element 1009
, And after being compressed, is discharged into the motor room 1008. The lubricating oil separated from the refrigerant gas in the motor room 1008 is collected in an oil reservoir 1035.

As described above, the contact force between the tip of the high-stage vane 1039 and the high-stage piston 1009b is reduced by the high-stage compression element 1
A pressure difference between the discharge pressure of 009 and the suction pressure of the high-stage compression element 1009 (low-stage discharge pressure) acts. Similarly,
The differential pressure between the discharge pressure and the suction pressure of the low-stage compression element 1007 acts on the contact force between the tip of the low-stage vane 1038 and the low-stage piston 1007b. Therefore, low stage vanes 103
In this configuration, the friction loss power and the amount of wear at the tip of No. 8 are reduced by half as compared with the case where the differential pressure between the high-stage discharge pressure and the low-stage suction pressure acts.

Further, the lubricating oil supplied from the oil reservoir 1035 to the low-stage vane rear chamber 1044 is introduced from an oil passage 1061 provided in the middle plate 1036.
When the oil level of 35 is lower than the oil passage 1061, there is a problem that the lubricating oil cannot be supplied to the low-stage vane rear chamber 1044.

As a measure for solving this problem, the oil suction pipe 1023 shown in FIG. 13 of the above-mentioned publication (Japanese Patent Laid-Open Publication No. Hei 4-18787) should be inserted into the oil reservoir shown in FIG. A method of connecting the oil passage 1061 to the bottom of the oil reservoir 1035 is also conceivable. However,
In a state where the oil passage 1061 communicates with the bottom of the oil reservoir 1035, when the lubricating oil at the bottom of the oil reservoir 1035 runs out,
This poses a serious problem that lubrication from the lower end of the drive shaft 1006 to each sliding portion of the drive shaft 1006 becomes impossible.

[0012]

However, such a configuration as shown in FIGS. 5 to 7 has the following problems.

That is, the intermediate-pressure lubricating oil flowing into the low-stage vane rear chamber 1044 is
Immediately flows down to the low-stage discharge chamber 1045 and passes through, so that lubrication of the sliding surface of the low-stage vane 1038 becomes insufficient. As a result, the pressure is reduced, and
The refrigerant gas contained in the lubricating oil supplied to 4 is separated,
There is a problem that leakage occurs through the sliding gap of the low-stage vane 1038 into the low-stage cylinder, which causes a reduction in the compression efficiency of the low-stage compression element 1007.

The present invention has been made to solve such a conventional problem, and has as its object to secure a sufficient amount of lubricating oil in a low-stage vane rear chamber.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention avoids installing an outlet of an oil passage flowing out from a low-stage vane rear chamber to a low-stage discharge chamber at a lower portion of the low-stage vane rear chamber. The purpose of this is to secure lubricating oil staying in the lower stage vane rear chamber.

The opening of the oil passage from the low-stage vane rear chamber to the low-stage discharge chamber side allows the lubricating oil supplied from the oil reservoir to the low-stage vane rear chamber to accumulate. To improve the compression efficiency and the durability of the low stage vane.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first aspect of the present invention forms a two-stage compression mechanism in which a low-stage compression element and a high-stage compression element are sequentially connected in series, and protrudes and retracts in each cylinder of each compression element. Among the vanes partitioning the interior of each cylinder into a suction chamber and a compression chamber while retracting), lubricating oil that acts on discharge pressure is introduced into the high-stage vane rear chamber of the high-stage compression element high-stage vane, The lubricating oil acting on the discharge pressure is introduced into the low-stage vane rear chamber of the low-stage compression element at a reduced pressure, and the lubricating oil in the low-stage vane rear chamber is supplied to the suction side of the high-stage compression element. In the configuration in which the oil supply passage is provided, the introduction opening for introducing the lubricating oil acting on the discharge pressure into the low-stage vane back pressure chamber is provided so that the lubricating oil flows from the low-stage vane back chamber to the suction side of the high-stage compression element. It is provided at a position lower than the exit. According to this configuration, the lubricating oil in the low-stage vane rear chamber stays at an intermediate pressure state between the compressor discharge pressure and the suction pressure, and is supplied to the sliding portion of the low-stage vane. The gap can be sealed with an oil film.

According to a second aspect of the present invention, the low-stage discharge chamber of the low-stage compression element is disposed in the middle of a path for allowing the lubricating oil to flow from the low-stage vane rear chamber to the suction side of the high-stage compression element. . According to this configuration, the pressure in the low-stage vane rear chamber is equivalent to the pressure in the low-stage discharge chamber. As a result, the contact force between the tip of the low-stage vane and the low-stage piston is stabilized, and the durability of the tip of the vane is improved.

According to a third aspect of the present invention, the introduction opening for introducing the lubricating oil into the low-stage vane back pressure chamber is disposed in the low-stage vane rear chamber so as to urge the cylinder side of the low-stage vane. This is connected to the spring mounting hole of the spring means. According to this configuration, the spring means and the back surface of the low-stage vane that contacts the spring means are reliably lubricated by the lubricating oil supplied to the low-stage vane rear chamber, and the durability of both parts is improved. .

According to a fourth aspect of the present invention, a two-stage compression mechanism in which a low-stage compression element and a high-stage compression element are sequentially connected in series is formed, and each compression element is moved in and out of each cylinder (forward and backward). Among the vanes that divide the interior of each cylinder into a suction chamber and a compression chamber, lubricating oil that acts on the discharge pressure is introduced into the high-stage vane rear chamber of the high-stage compression element of the high-stage compression element, and the low-stage compression element In the low-stage vane, low-pressure vane rear chambers are provided with oil supply passages that reduce the pressure of the lubricating oil that acts on the discharge pressure and introduce the lubricating oil in the low-stage vane rear chamber to the suction side of the high-stage compression element. In the above configuration, the oil supply passage for introducing the lubricating oil on which the discharge pressure acts into the low-stage vane rear chamber is provided on the drive shaft so as to supply the lubricating oil from the end of the drive shaft to the drive shaft of the two-stage compression mechanism. It is formed so as to pass through a pump means. With this configuration, even when the oil level in the oil reservoir is lowered, the pump means can suck up the lubricating oil and supply it to the low-stage vane rear chamber.

According to a fifth aspect of the present invention, a passage provided in a middle plate for connecting the low-stage compression element and the high-stage compression element is disposed in the middle of the path between the pump means and the low-stage vane rear chamber. . With this configuration, the lubricating oil pumped and stored in the space between the pistons of the low-stage compression element and the high-stage compression element can be continuously supplied to the low-stage vane rear chamber.

According to a sixth aspect of the present invention, a throttle passage portion is provided in a passage provided in the middle plate. According to this configuration, the path of the radial throttle passage portion extending from the drive shaft side to the outer peripheral direction of the intermediate plate in the throttle passage portion becomes longer, the depressurizing action of the lubricating oil is stabilized, and the flow to the low-stage vane rear chamber is reduced. Lubricating oil supply is stabilized.

According to a seventh aspect of the present invention, a gas vent passage communicating with the inside of the closed vessel is arranged on the discharge side of the pump means. According to this configuration, the degassed lubricating oil is sent to the low-stage vane rear chamber and the high-stage compression element, thereby improving the durability of the sliding portion of the low-stage vane and increasing the compression efficiency of the high-stage compression element.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a longitudinal section of a rolling piston type rotary two-stage compressor using carbon dioxide refrigerant, FIG. 2 shows a partial longitudinal section of the compressor, and FIG. FIG. 2 is an external view of a low-stage cylinder block of the machine.

An electric motor 2 and a two-stage compression mechanism 3 are arranged below the electric motor 2 in the closed container 1. Two-stage compression mechanism 3
Is a high-stage compression element 4, a low-stage compression element 5 disposed therebelow, an intermediate plate 6 disposed between the high-stage compression element 4 and the low-stage compression element 5, a high-stage compression element 4, A drive shaft 7 connected to the rotor 2a of the electric motor 2 for driving the low-stage compression element 5, a main bearing 9 fixed to a high-stage cylinder block 8 of the high-stage compression element 4 for supporting the drive shaft 7, and And a sub-bearing 11 fixed to the low-stage cylinder block 10 of the low-stage compression element 5.

The high-stage cylinder block 8 is fixed to the closed vessel 1 by welding, and the middle plate 6 and the low-stage cylinder block 10 are fixed to the high-stage cylinder block 8.

High-stage discharge cover 12 attached to main bearing 9
Form a high-stage discharge chamber 13 together with the main bearing 9.

The low-stage discharge cover 26 surrounding the outer peripheral portions of the middle plate 6, the low-stage cylinder block 10, and the auxiliary bearing 11 and attached to the high-stage cylinder block 8 via a seal member 98 has a low-stage discharge chamber 27. Is formed. An O-ring 97 is interposed between the low-stage discharge cover 26 and the auxiliary bearing 11,
The oil reservoir 32 and the low-stage discharge chamber 27 in the closed container 1 are pressure-isolated from each other.

Between the low-stage discharge chamber 27 and the high-stage discharge chamber 13, the auxiliary bearing 11, the low-stage cylinder block 10, the middle plate 6,
The high-stage cylinder block 8 and the main bearing 9 are connected to each other by a bypass passage 96 penetrating therethrough. Bypass passage 9
6 has a valve body 95 that opens and closes the bypass passage 96;
A spring means 94 for urging the valve element 95 is provided, and forms a check valve mechanism that allows only the flow of the refrigerant gas from the low-stage discharge chamber 27 to the high-stage discharge chamber 13.

At the lower end of the oil hole 7a penetrating the drive shaft 7, a centrifugal pump means 93 is mounted. The centrifugal pump means 93 causes the auxiliary bearing 11 and the inside of the low-stage piston 70 of the low-stage compression element 5 to move. High-stage piston 6 of high-stage compression element 4
On the inner surface of the main bearing 5 and on each sliding surface of the main bearing 9, there is formed a path through which lubricating oil in the oil reservoir 32 is supplied.

A high-stage vane on the side opposite to the cylinder of the high-stage vane 15 arranged in contact with the outer peripheral surface of the high-stage piston 65 in the cylinder of the high-stage compression element 4 to partition the inside of the cylinder into a suction chamber and a compression chamber. The rear chamber 16 communicates with the oil sump 32.

Similarly to the above, the low-stage vane rear chamber 3 disposed on the side opposite to the cylinder of the low-stage vane 92 of the low-stage compression element 5.
A spring means (coil spring) 91 is disposed at 3, and presses the tip of the low-stage vane 92 against the low-stage piston 70. A spring mounting hole 34 provided in the low-stage vane rear chamber 33 for mounting a spring means (coil spring) 91 communicates with the oil reservoir 32 in the closed casing 1 through a path described below.

That is, the spring mounting hole 34 is formed between the low-stage cylinder block 10, the outer peripheral portion of the middle plate 6, and the low-stage discharge cover 26.
, An oil hole 68 provided in the middle plate 6 and having a throttle portion, and a radial oil hole 7b provided orthogonally to the oil hole 7a of the drive shaft 7 so as to communicate with each other. I have.

The low-stage vane rear chamber 33 communicates with the low-stage discharge chamber 27 through an oil supply passage 88 having an outlet 89 above the spring mounting hole 34.

The low-stage discharge chamber 27 communicates with the suction chamber of the high-stage compression element 4 through an intermediate communication passage 87 provided through the auxiliary bearing 11, the high-stage cylinder block 10, and the middle plate 6.

An electric connection terminal 86 connected to the electric motor 2 is arranged in a flat portion at the center of the upper wall of the closed casing 1, and an external connection cluster 85 bound by an insulating resin material is inserted into the external connection terminal 86a. ing. The internal shape of the terminal cover 84 surrounding the external connection cluster 85 is such that, for example, even when the terminal constituting the electric connection terminal 86 is partially released due to the high-pressure CO 2 gas pressure in the closed container 1, the external connection cluster 85 Is the external connection terminal 86a
Is set so that it does not deviate from

The discharge pipe 83 arranged on the upper wall of the closed container 1
In the vicinity of the open end on the side of the electric motor chamber 29, a shielding plate 82 opened on the inner wall side of the closed casing 1 is arranged to prevent direct gas outflow from the electric connection terminal 86 side to the discharge pipe 83. I have.

The operation of the rolling piston type rotary two-stage compressor using the carbon dioxide refrigerant gas configured as described above will be described with reference to FIGS. 1, 2 and 3.

The refrigerant gas sucked into the cylinder of the low-stage compression element 5 is compressed and then discharged to the low-stage discharge chamber 27. The refrigerant gas discharged from the low-stage discharge chamber 27 is taken into the suction chamber of the high-stage compression element 4 via the intermediate communication passage 87, and after compression, discharged into the high-stage discharge chamber 13, and
Is discharged to Part of the lubricating oil mixed into the refrigerant gas discharged into the electric motor room 9 is separated and collected in the oil reservoir 32.
The high-pressure discharge refrigerant gas from which a part of the lubricating oil has been separated is sent to a compressor external piping system through a discharge pipe 83.

The lubricating oil in the oil reservoir 32 to which the refrigerant gas pressure discharged from the high-stage compression element 4 acts is centrifugally pumped by a centrifugal pump 93 disposed at the lower end of the drive shaft 7.
The oil is discharged to the motor chamber 29 via the oil hole 7b in the radial direction, the inner space of the low-stage piston 70, the inner space of the high-stage piston 65, and the bearing sliding surface of the main bearing 9 in that order.
Return to.

The refrigerant gas mixed into the lubricating oil discharged from the centrifugal pump means 93 into the oil hole 7a in the drive shaft 7 is discharged from the upper opening end of the oil hole 7a to the motor chamber 29. As a result, the lubricating oil in the oil hole 7a is degassed,
A good oil film without gas entrapment is formed on the inner surface sliding surface of the low-stage piston 70, the inner surface sliding surface of the high-stage piston 65, and the bearing sliding surface of the main bearing 9.

The lubricating oil during the lubrication process of the sliding portion of the drive shaft 7 is reduced to an intermediate pressure through the oil hole 68 having the throttle portion of the intermediate plate 6, and then the gap passage 90, the spring mounting hole 34 ,
The low-stage discharge chamber 2 sequentially passes through the low-stage vane back chamber 33, the outlet 89 above the spring mounting hole 34, and the intermediate communication passage 87.
7 is supplied. Since the intermediate communication passage 87 is a passage in which no throttling action occurs, the low-stage vane back pressure chamber 33 has a pressure equivalent to that of the low-stage discharge chamber 27.

The outlet 89 of the intermediate communication passage 88 which communicates the low-stage vane back pressure chamber 33 with the low-stage discharge chamber 27 has a spring mounting hole 34.
The lubricating oil in the low-stage vane back pressure chamber 33 owes to its own weight even when the compressor is stopped.
7, the lubrication of the clearance of the sliding portion of the low-stage vane 92 at the initial stage of the restart of the compressor is provided.

Naturally, the lubricating oil in the low-stage vane back pressure chamber 33 is sufficiently ensured even during the operation of the compressor, and the oil film sealing action of the sliding portion gap of the low-stage vane 92 and the low-stage vane 92
To the low-stage piston.

This pressing force is reduced by half as compared with the case where the lubricating oil in the oil reservoir 32 is introduced into the low-stage vane back chamber 33 without being decompressed. The sliding friction loss with the tip of the vane 92 is small, and the sliding portion wear is small.

The low-stage vane back chamber 33 is pressure-isolated from the inside of the closed vessel 1 by a seal member interposed between the high-stage cylinder block 8 and the low-stage discharge cover 26. , The refrigerant gas in the closed vessel 1 does not leak into the low-stage vane rear chamber 33.

The low-stage vane rear chamber 33 to the low-stage discharge chamber 27
The appropriate amount of lubricating oil introduced into the suction chamber of the high-stage compression element 4 via the valve is subjected to an oil film sealing action in the gap of the compression chamber of the high-stage compression element 4, thereby improving the compression efficiency.

As described above, according to the above-described embodiment, the two-stage compression mechanism 3 in which the low-stage compression element 5 and the high-stage compression element 4 are sequentially connected in series is formed, and each compression element protrudes and retracts in each cylinder. Among the vanes that partition the interior of each cylinder into a suction chamber and a compression chamber while moving forward and backward, lubrication in which discharge pressure acts is applied to the high-stage vane back chamber 16 of the high-stage vane 15 of the high-stage compression element 4. In addition to introducing oil, lubricating oil acting on discharge pressure is introduced into the low-stage vane rear chamber 33 of the low-stage vane 92 of the low-stage compression element 5 under reduced pressure, and the lubricating oil in the low-stage vane rear chamber 33 is increased. In the configuration in which each oil supply passage for supplying to the suction side of the stage compression element 4 is provided, an introduction opening (spring mounting hole 3) for introducing lubricating oil acting on discharge pressure into the low stage vane back pressure chamber 33.
4) is provided at a position lower than the outlet 89 for discharging the lubricating oil from the low-stage vane rear chamber 33 to the suction side of the high-stage compression element 4, so that the lubricating oil in the low-stage vane rear chamber 33 is low-stage vane. Without passing through the rear chamber 33, the pressure always stays at an intermediate pressure between the compressor discharge pressure and the suction pressure. As a result, the lubricating oil is supplied to the low-stage vane 9 from the state where the differential pressure oil supply cannot be performed at the initial stage of the compressor operation to the stable operation after the compressor is started.
The durability of the low-stage vane 92 can be improved by supplying an appropriate amount to the sliding portion 2.

Further, according to the above-described embodiment, the low-stage discharge chamber 27 of the low-stage compression element 5 is disposed in the middle of the path for allowing the lubricating oil to flow from the low-stage vane rear chamber 33 to the suction side of the high-stage compression element 4. Thus, the pressure in the low-stage vane rear chamber 33 always corresponds to the pressure in the low-stage discharge chamber 27. As a result, the contact force between the tip of the low-stage vane 92 and the low-stage piston 70 is stabilized, the oil film formation at the tip of the low-stage vane 92 is stabilized, and the durability of the low-stage vane 92 can be improved.

Further, according to the above embodiment, the introduction opening for introducing the lubricating oil into the low-stage vane back pressure chamber 33 is formed by the low-stage vane 9.
The spring means 94 is connected to the spring mounting hole 34 of the spring means 94 disposed in the low-stage vane rear chamber 33 so as to urge the opposite side of the cylinder. 92 is a low-stage vane rear chamber 33
The lubricating oil supplied to the lubricating oil can surely lubricate, and the durability of both parts can be improved.

According to the above embodiment, the low-stage compression element 5
And a high-stage compression element 4 are sequentially connected in series to form a two-stage compression mechanism 3 for partitioning each cylinder into a suction chamber and a compression chamber while protruding and retracting (forward / backward) inside each cylinder of each compression element. Of the vanes, lubricating oil acting on the discharge pressure is introduced into the high-stage vane rear chamber 16 of the high-stage vane 15 of the high-stage compression element 4, and the low-stage vane back of the low-stage vane 92 of the low-stage compression element 5 is introduced. In a configuration in which lubricating oil acting on the discharge pressure is introduced into the chamber 33 under reduced pressure and each oil supply passage is provided to supply the lubricating oil in the low-stage vane rear chamber 33 to the suction side of the high-stage compression element 4, The lubricating oil acting on the lower stage vane rear chamber 33
Is formed so as to supply lubricating oil from the end of the drive shaft 7 to the drive shaft 7 of the two-stage compression mechanism 3 through a centrifugal pump means 93 provided on the drive shaft 7. Even when the oil level in the oil reservoir 32 is lowered, the lubricating oil in the oil reservoir 32 is sucked up by the centrifugal pump means 93 without flowing the refrigerant gas in the closed vessel 1 into the low-stage vane rear chamber 33, and the low-stage vane Since oil can be supplied to the rear chamber 33, the durability of the sliding portion of the low-stage vane 92 can be ensured.

According to the above-described embodiment, an oil hole provided in the middle plate 6 for connecting the low-stage compression element 5 and the high-stage compression element 4 in the middle of the path between the centrifugal pump means 93 and the low-stage vane rear chamber 33. 68, the lubricating oil pumped and stored in the space between the pistons (65, 70) of the low-stage compression element 5 and the high-stage compression element 4 is continuously supplied to the low-stage vane rear chamber 33.
Can be refueled. As a result, it is possible to supply both the drive shaft 7 and the low-stage vane 92 to both members, to centrally supply the oil without dispersing the amount of oil supply, and to improve the durability of the compressor by effectively utilizing the lubricating oil in the oil reservoir 32. Can be achieved.

According to the above embodiment, the oil passage 68 provided in the middle plate 6 is used as the throttle passage, so that the throttle passage is formed in the radial direction from the drive shaft 7 side to the outer peripheral direction of the middle plate 6. The path of the passage section is lengthened to stabilize the lubricating oil decompression action, stabilize the amount of lubricating oil supplied to the low-stage vane rear chamber 33, and reduce the low-stage The durability of the vane 92 can be improved.

According to the above embodiment, the upper end of the oil hole 7a provided in the drive shaft 7 is opened to the motor chamber 29, so that the oil hole 32a, the drive shaft 7, and the middle plate 6 are sequentially passed through the lower portion. The lubricating oil supplied to the step vane rear chamber 33 can be degassed, and the durability of the low step vane 92 can be further improved by forming a good oil film on the sliding surface of the low step vane 92. Further, the high-stage compression element 4
The compression efficiency can be improved by reducing the amount of refrigerant gas in the lubricating oil flowing into the compressor.

(Embodiment 2) FIG. 4 shows a rolling piston type rotary two-stage compressor using a carbon dioxide refrigerant in which an outlet 89 communicating with the low-stage discharge chamber 27 provided in the cylinder block 10 in FIG. 7 shows an embodiment provided in another manner.

That is, the outlet 89a leading to the low-stage discharge chamber 27 is provided in an outflow groove 89b provided on the middle plate contact surface side of the low-stage cylinder block 10a. This outlet 8
This shows an embodiment in which the position of 9a is shifted to realize communication with the low-stage discharge chamber 27, and processing of the outlet 89a is easy. Other functions and effects are the same as those in the first embodiment, and thus description thereof is omitted.

In the above embodiment, a rolling piston type rotary two-stage compressor using a carbon dioxide refrigerant has been described, but a two-stage rolling for compressing other gases (eg, oxygen, nitrogen, helium, air, etc.). The same operation and effect are produced in the case of a piston type rotary compressor.

[0059]

As is apparent from the above embodiment, the first aspect of the present invention is as follows.
The invention described in (1) forms a two-stage compression mechanism in which a low-stage compression element and a high-stage compression element are sequentially connected in series, and a suction chamber is formed in each cylinder of each compression element while protruding and retracting (forward / backward). The lubricating oil that acts on the discharge pressure is introduced into the high-stage vane rear chamber of the high-stage compression element, and the low-stage vane of the low-stage compression element is low. In the configuration in which lubricating oil that acts on the discharge pressure is introduced into the stage vane rear chamber under reduced pressure, and each oil supply passage that supplies the lubricating oil in the low stage vane rear chamber to the suction side of the high stage compression element is provided,
The introduction opening for introducing the lubricating oil on which the discharge pressure acts into the low-stage vane back pressure chamber is provided at a position lower than the outlet from which the lubricating oil flows out from the low-stage vane back chamber to the suction side of the high-stage compression element. It is. According to this configuration, the lubricating oil in the low-stage vane rear chamber always stays at an intermediate pressure between the compressor discharge pressure and the suction pressure without passing through the low-stage vane rear chamber. As a result, in all operating states from the state where the differential pressure oil supply cannot be performed at the initial stage of the compressor startup to the stable operation after the startup, an appropriate amount of the lubricating oil is supplied to the sliding portion of the low-stage vane,
The durability of the low-stage vane can be improved.

According to a second aspect of the present invention, the low-stage discharge chamber of the low-stage compression element is disposed in the middle of the path for allowing the lubricating oil to flow out of the low-stage vane rear chamber to the suction side of the high-stage compression element. . According to this configuration, the pressure in the low-stage vane rear chamber always corresponds to the pressure in the low-stage discharge chamber. As a result, the contact force between the tip of the low-stage vane and the low-stage piston is stabilized, and the oil film formation at the tip of the low-stage vane is stabilized, so that the durability of the low-stage vane can be improved.

According to the third aspect of the present invention, the introduction opening for introducing the lubricating oil into the low-stage vane back pressure chamber is disposed in the low-stage vane rear chamber so as to urge the side opposite to the cylinder of the low-stage vane. This is connected to the spring mounting hole of the spring means. According to this configuration, the spring means and the back surface of the low-stage vane in contact with the spring means can be reliably lubricated by the lubricating oil supplied to the low-stage vane back chamber, and the durability of both parts can be improved. Can be improved.

According to a fourth aspect of the present invention, a two-stage compression mechanism in which a low-stage compression element and a high-stage compression element are connected in series is formed, and each compression element protrudes and retracts in each cylinder (forward and backward).
Of the vanes partitioning the interior of each cylinder into a suction chamber and a compression chamber, lubricating oil that acts on discharge pressure is introduced into the high-stage vane rear chamber of the high-stage vane of the high-stage compression element,
Lubricating oil acting on the discharge pressure is introduced under reduced pressure into the low-stage vane rear chamber of the low-stage vane of the low-stage compression element, and then the suction side of the high-stage compression element passes through the low-stage vane back pressure chamber. In the configuration provided with each oil supply passage communicating with the oil supply passage, the oil supply passage for introducing the lubricating oil acting on the discharge pressure into the rear chamber of the low-stage vane is provided to supply the lubricating oil from the lower part of the drive shaft to the drive shaft of the two-stage compression mechanism. Are formed so as to pass through a pump means provided on the drive shaft. According to this configuration, even when the oil level of the oil sump is lowered, the lubricating oil in the oil sump is sucked up by the pump means without the refrigerant gas in the closed vessel flowing into the low-stage vane rear chamber, and the low-stage vane is removed. Since oil can be supplied to the rear chamber, durability of the sliding portion of the low-stage vane can be ensured.

According to a fifth aspect of the present invention, a passage provided in a middle plate connecting the low-stage compression element and the high-stage compression element is disposed in the middle of the path between the pump means and the low-stage vane rear chamber. . According to this configuration, the lubricating oil pumped and stored in the space between the pistons of the low-stage compression element and the high-stage compression element can be continuously supplied to the low-stage vane rear chamber. As a result, it is possible to supply both the drive shaft and the low-stage vane to both members, to centralize lubrication without dispersing the lubrication amount, and to improve the durability of the compressor by effectively utilizing the lubricating oil in the oil reservoir. Can be.

According to a sixth aspect of the present invention, a throttle passage portion is provided in a passage provided in the middle plate. According to this configuration, the path of the throttle passage portion in the radial direction from the drive shaft side to the outer peripheral direction of the intermediate plate can be made longer in the throttle passage portion. The lubricating oil supply amount can be stabilized, and the durability of the low-stage vane can be improved by continuously supplying oil to the low-stage vane rear chamber.

According to a seventh aspect of the present invention, a gas vent passage communicating with the inside of the closed vessel is arranged on the discharge side of the pump means. According to this configuration, the lubricating oil supplied to the low-stage vane rear chamber via the oil reservoir, the drive shaft, and the middle plate in order is degassed, and the sliding surface of the low-stage vane has a good oil film. Thus, the durability of the low-stage vane can be further improved. Further, there is an effect that the compression efficiency can be improved by reducing the amount of refrigerant gas in the lubricating oil flowing into the high-stage compression element from the low-stage vane rear chamber.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rolling piston type rotary two-stage compressor showing a first embodiment of the present invention.

FIG. 2 is a partial sectional view of a compression mechanism in the compressor.

FIG. 3 is an external view of a high-stage cylinder block in the compressor.

FIG. 4 is an external view of a high-stage cylinder block in a rolling piston type rotary two-stage compressor showing a second embodiment of the present invention.

FIG. 5 is a connection diagram of a conventional rolling piston type rotary two-stage compressor and a refrigeration cycle piping system.

FIG. 6 shows a rolling piston type rotary type 2 of the compressor.
Longitudinal cross section of the stage compressor

FIG. 7 is a partial vertical sectional view of the compressor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Electric motor 3 Two-stage compression mechanism 4 High-stage compression element 5 Low-stage compression element 6 Middle plate 7 Drive shaft 7a Oil hole 15 High-stage vane 16 High-stage vane rear room 27 Low-stage discharge room 29 Motor room 33 Low-stage Vane back chamber 34 Inlet opening 68 Oil hole 89 Outlet 92 Low stage vane 93 Pump means 94 Spring means

Claims (7)

[Claims] 1. A two-stage compression mechanism in which a low-stage compression element and a high-stage compression element are sequentially connected in series is formed, and the inside of each cylinder of each compression element is sucked while moving in and out (forward and backward) of each cylinder. Of the vanes partitioned into a chamber and a compression chamber, a lubricating oil acting on a discharge pressure is introduced into a high-stage vane rear chamber of a high-stage vane of the high-stage compression element, and a low stage of the low-stage compression element is introduced. Each oil supply passage is provided in the low-stage vane rear chamber of the vane to reduce the pressure of the lubricating oil acting on the discharge pressure and to introduce the lubricating oil in the low-stage vane rear chamber to the suction side of the high-stage compression element. In the configuration, an introduction opening for introducing the lubricating oil acting on the discharge pressure into the low-stage vane back pressure chamber,
A rotary two-stage compressor provided at a position lower than an outlet through which lubricating oil flows out from the low-stage vane rear chamber to the suction side of the high-stage compression element. 2. The rotary two-stage compression according to claim 1, wherein a low-stage discharge chamber of the low-stage compression element is disposed in a middle of a path through which the lubricating oil flows out from the low-stage vane rear chamber to the suction side of the high-stage compression element. Machine. 3. An introduction opening for introducing lubricating oil into the low-stage vane back pressure chamber is provided in a spring mounting hole of a spring means disposed in the low-stage vane rear chamber so as to urge the side opposite to the cylinder of the low-stage vane. The rotary two-stage compressor according to claim 1, wherein the two-stage compressor is in communication. 4. A two-stage compression mechanism in which a low-stage compression element and a high-stage compression element are sequentially connected in series is formed, and each compression element is moved in and out of each cylinder (forward and backward). Among the vanes partitioning the suction chamber and the compression chamber, lubricating oil acting on discharge pressure is introduced into the high-stage vane rear chamber of the high-stage vane of the high-stage compression element, and the low-stage compression element is introduced. The lubricating oil acting on the discharge pressure is introduced under reduced pressure into the low-stage vane rear chamber of the low-stage vane, and then communicates with the suction side of the high-stage compression element via the low-stage vane back pressure chamber. In the configuration in which each oil supply passage is provided, the oil supply passage for introducing the lubricating oil acting on the discharge pressure into the low-stage vane rear chamber is configured to supply the lubricating oil from the lower part of the drive shaft to the drive shaft of the two-stage compression mechanism. A row formed through a pump means provided on the drive shaft. Tally type two-stage compressor. 5. The rotary two-stage compression according to claim 4, wherein a passage provided in an intermediate plate connecting the low-stage compression element and the high-stage compression element is arranged in the middle of a path between the pump means and the low-stage vane rear chamber. Machine. 6. The rotary two-stage compressor according to claim 5, wherein a throttle passage portion is provided in a passage provided in the middle plate. 7. The rotary type 2 according to claim 5, wherein a gas vent passage communicating with the inside of the closed vessel is arranged on the discharge side of the pump means.
Stage compressor.