JP2008121541A - Rotary two-stage compressor - Google Patents

Abstract

An object of the present invention is to provide a rotary two-stage compressor with high compressor efficiency.
A rotary two-stage compressor according to the present invention includes a rotary shaft 2 having two eccentric portions 5a and 5b, and rollers 11a and 11b that revolve by eccentric rotation of the eccentric portions 5a and 5b, respectively. The compression mechanism part 20a and the compression part 20b for high pressure provided in 23b are provided with the compression mechanism part provided through the intermediate partition plate, and the refrigerating machine oil supplied to a compression mechanism part. The radial gap δ2 between the cylinder 10b and the roller 11b of the high pressure compression section 20b is made larger than the radial gap δ1 between the cylinder 10a and the roller 11a of the low pressure compression section 20a.
[Selection] Figure 2

Description

  The present invention relates to a rotary two-stage compressor used for a refrigeration cycle, and more particularly to setting a fitting clearance between components of a compression mechanism portion thereof.

  Conventionally, for example, a structure described in Patent Document 1 is known as a rotary two-stage compressor used in a refrigeration cycle. The conventional rotary two-stage compressor includes an electric motor including a stator and a rotor inside a sealed container. The rotating shaft connected to the electric motor has two eccentric portions. As compression mechanisms corresponding to these eccentric parts, a high-pressure compression part and a low-pressure compression part are provided in the inside of the hermetic container in order from the electric motor side. Each compression part revolves a roller by the eccentric rotation of the eccentric part of the rotating shaft. These eccentric portions have a phase difference of 180 °, and the phase difference in the compression process of each compression portion is 180 °. That is, the compression processes of the two compression units are in antiphase.

FIG. 5 schematically shows the configuration of the above-described conventional rotary two-stage compressor. The low-pressure compression section 20a includes a substantially cylindrical cylinder 10a, a substantially cylindrical roller 11a, and an end plate (not shown) that forms a compression chamber 23a. The compression chamber 23a is partitioned into a suction space and a compression space by a flat vane 18a. The roller 11a is fitted in the eccentric part 5a of the rotating shaft.
Similarly, the high-pressure compression section 20b includes a substantially cylindrical cylinder 10b, a substantially cylindrical roller 11b, and an end plate (not shown) that forms a compression chamber 23b. The compression chamber 23b is partitioned into a suction space and a compression space by a flat vane 18b. The roller 11b is fitted in the eccentric part 5b of the rotating shaft.

  As shown by the arrows in FIG. 5, the gas refrigerant as the working fluid is sucked into the low-pressure compression section 20a from the suction port 25a through the low-pressure side suction pipe 31 at a low pressure Ps, and is compressed to an intermediate pressure Pm. The The discharge valve 28a opens the discharge port 26a at a predetermined intermediate pressure Pm, and the gas refrigerant is discharged into the discharge space 33 communicated with the low-pressure compressor 20a. The discharged gas refrigerant passes through the discharge space 33 and flows to the intermediate flow path pipe 30. Next, the gas refrigerant having the intermediate pressure Pm is sucked into the high-pressure compression section 20b through the intermediate flow path pipe 30 and the suction port 25b, and is compressed to the high pressure Pd. The discharge valve 28b opens the discharge port 26b at a predetermined high pressure Pd, and the gas refrigerant is discharged into the sealed container 13. The discharged high-pressure Pd gas refrigerant is discharged from the discharge pipe 27 to the outside of the rotary two-stage compressor.

  The refrigerating machine oil 41 enclosed in the lower part of the hermetic container 13 is supplied from between the sliding parts to the compression parts 20a and 20b by a differential pressure between the inner pressure of the hermetic container 13 and the inner pressure of each of the compression chambers 23a and 23b. . Specifically, those supplied from the oil supply holes 43 in the rotating shaft through the eccentric portions 5a and 5b and the rollers 11a and 11b, between the rollers 11a and 11b and the end plates, between the cylinders 10a and 10b and the vanes 18a and 18b, etc. There are some that are supplied directly from. The refrigerating machine oil 41 is used for improving the slidability of each sliding component and suppressing refrigerant leakage from between the sliding components. The supplied refrigerating machine oil 41 flows while mixed in the refrigerant gas, and adheres to the boundary walls constituting the compression chambers 23a and 23b, that is, the cylinders 10a and 10b and the rollers 11a and 11b as shown in FIG. The oil films 42a and 42b are formed.

For example, Patent Document 2 discloses a fitting size between sliding parts of a rotary two-stage compressor in which the inside of the hermetic container 13 has a high pressure Pd. In the prior art described in Patent Document 2, in order to prevent the high-pressure gas refrigerant in the hermetic container 13 from leaking too much into the low-pressure compressor 20a having a large pressure difference, this is called the side clearance of the low-pressure compressor 20a. The minimum radial gap between the outer peripheral surface of the roller 11a and the inner peripheral surface of the cylinder 10a is made smaller than the minimum radial gap between the outer peripheral surface of the roller 11b of the high pressure compression section 20b and the inner peripheral surface of the cylinder 10b. It is said.
JP-A-60-128990 (5th page, Fig. 1) Japanese Patent Laid-Open No. 6-81786 (page 7, FIG. 3)

  In each compression part 20a, 20b, in order to avoid the solid contact with the outer peripheral surface of roller 11a, 11b and the inner peripheral surface of cylinder 10a, 10b, both are arrange | positioned by providing a radial clearance. If this radial gap is large, a gas refrigerant leaks from the compression space of each compression chamber 23a, 23b to the suction space. If the radial gap is small, the frictional resistance and The oil film reaction force increases and the compressor efficiency decreases. That is, the influence of the radial gap between the rollers 11a and 11b and the cylinders 10a and 10b varies depending on the thickness of the oil films 42a and 42b.

  In the case of a rotary two-stage compressor, the low pressure compressor 20a and the high pressure compressor 20b are connected in series as shown in FIG. 5, so that the refrigerating machine oil 41 supplied by the low pressure compressor 20a is compressed. The gas refrigerant is mixed and discharged as it is to the high-pressure compressor 20b. In the high pressure compressor 20b, the refrigeration oil 41 is also supplied from between the sliding parts as described above. Therefore, the high pressure compressor 20b contains the refrigeration oil 41 more than the low pressure compressor 20a. As a result, the oil film 42b of the high pressure compressor 20b is thicker than the oil film 42a of the low pressure compressor 20a.

However, since the conventional technology of Patent Document 2 does not consider the difference in thickness between the oil film 42a of the low-pressure compression section 20a and the oil film 42b of the high-pressure compression section 20b, the compression sections 20a and 20b have the above-described difference. The radial gap is the same. Therefore, since the oil film 42b of the high-pressure compression unit 20b is thick, excessive frictional resistance and oil film reaction force are generated, reducing the compressor efficiency.
The present invention has been made in view of the above problems, and an object thereof is to provide a rotary two-stage compressor having high compressor efficiency.

In order to achieve the above object, a rotary two-stage compressor according to the present invention includes an inner diameter D2 of a cylinder constituting a high-pressure compression section, an outer diameter d2 of a roller, and an eccentricity of the eccentric part from the rotation center of the rotating shaft. The radial gap δ2 between the outer peripheral surface of the roller of the high-pressure compression unit and the inner peripheral surface of the cylinder determined from the amount e2 is larger than the radial gap δ1 between the outer peripheral surface of the roller of the low-pressure compression unit and the inner peripheral surface of the cylinder. It is characterized by.
Further, the relationship between the radial gap δ1 of the low-pressure compression section and the radial gap δ2 of the high-pressure compression section is 1 <(δ2 / δ1) <3.

  According to the present invention, a rotary two-stage compressor with high compressor efficiency can be provided.

Embodiments according to the present invention will be described in detail with reference to FIGS. 1 to 4 as appropriate.
FIG. 1 is a longitudinal sectional view of a rotary two-stage compressor according to this embodiment. A rotary two-stage compressor (hereinafter referred to as a compressor) 1 includes a hermetic container 13 including a lid portion 12, a bottom portion 21, and a trunk portion 22. An electric motor 14 having a stator 7 and a rotor 8 is provided above the inside of the sealed container 13. The rotor shaft 8a of the electric motor 14 and the rotary shaft 2 of the compression mechanism section 3 to be described later are connected in an integral structure.
The rotor shaft 8a and the rotating shaft 2 may be connected with a fitting structure.

The rotating shaft 2 includes two eccentric portions 5a and 5b, and is pivotally supported by a main bearing 9 having an end plate portion 9a and a sub bearing 19 having an end plate portion 19a.
The compression mechanism section 3 includes a main bearing 9, a high-pressure compression section 20b, an intermediate partition plate 15, a low-pressure compression section 20a and a sub-bearing 19, and a substantially disc-shaped cover in order from the motor 14 side with respect to the rotary shaft 2. 35 is laminated and integrated with a fastening element 36 such as a bolt.
The main bearing 9 is fixed to the inner wall of the body portion 22 by welding. Here, the end plate portion 9a, the intermediate partition plate 15 and the end plate portion 19a of the main bearing 9 constitute a partition member in the present invention.

  Next, the configuration of the low-pressure compressor 20a and the high-pressure compressor 20b will be described with reference to FIGS. FIG. 2 is a side view of the compression unit for low pressure. In FIG. 2, the reference numerals corresponding to the respective configurations and dimensions of the high-pressure compression section are shown in parentheses. However, the phase of the compression process is shifted by 180 ° between the low pressure compressor 20a and the high pressure compressor 20b, but this relationship is not reflected in FIG.

(Compression section for low pressure)
As shown in FIG. 1, the compression chamber 23a of the low pressure compression section 20a includes a cylindrical roller fitted on the outer periphery of the end plate 19a of the auxiliary bearing 19, the cylindrical cylinder 10a, and the columnar eccentric part 5a. 11 a and an intermediate partition plate 15. As shown in FIG. 2, in the compression chamber 23a, a flat plate vane 18a connected to a biasing force applying means such as a coil spring (not shown) rotates around the outer periphery of the eccentric part 5a by the eccentric rotational movement of the eccentric part 5a. In addition, the compression chamber 23a is partitioned into a compression space and a suction space by moving back and forth while contacting the outer periphery of the roller 11a revolving around the rotation center O of the rotation shaft 2.
The suction port 25a opened on the inner peripheral surface of the cylinder 10a facing the suction space of the compression chamber 23a communicates with the body portion 22 and the low pressure side suction pipe 31 penetrating the side portion of the cylinder 10a. Further, the discharge port 26a opened in the end plate portion 19a facing the compression space of the compression chamber 23a is surrounded by the end plate portion 19a and the cover 35 via a discharge valve 28a that opens the discharge port 26a with a predetermined intermediate pressure Pm. The discharge space 33 communicates with the suction port 25b of the high-pressure compression section 20b, which will be described later, via the intermediate flow path pipe 30.
The discharge space 33 is isolated from the internal space in the sealed container 13 by the end plate portion 19a of the auxiliary bearing 19 and the cover 35.

(Compression section for high pressure)
Further, as shown in FIG. 1, the compression chamber 23b of the high-pressure compression section 20b has a cylindrical shape fitted on the outer periphery of the end plate portion 9a of the main bearing 9, the cylindrical cylinder 10b, and the columnar eccentric portion 5b. The roller 11b and the intermediate partition plate 15 are configured. As shown in FIG. 2, in the compression chamber 23b, a plate-like vane 18b connected to a biasing force applying means such as a coil spring (not shown) rotates around the outer periphery of the eccentric part 5b by the eccentric rotational movement of the eccentric part 5b. The compression chamber 23b is partitioned into a compression space and a suction space by moving forward and backward while contacting the outer periphery of the roller 11b revolving around the rotation center O of the rotation shaft 2 while performing the above-described operation.
A suction port 25b opened on the inner peripheral surface of the cylinder 10b facing the suction space of the compression chamber 23b communicates with the intermediate flow path pipe 30 penetrating the body portion 22 and the side portion of the cylinder 10b. Further, the discharge port 26b opened in the end plate portion 9a facing the compression space of the compression chamber 23b communicates with the inside of the sealed container 13 through a discharge valve 28b that opens the discharge port 26b with a predetermined high pressure Pd.
Further, in FIG. 1, a discharge pipe 27 penetrating the lid portion 12 of the sealed container 13 is communicated.

Each compression part 20a, 20b drives roller 11a, 11b because eccentric part 5a, 5b rotates eccentrically. As shown in FIG. 1, the eccentric portion 5a and the eccentric portion 5b have a phase difference of 180 °, and the phase difference in the compression process between the low pressure compression portion 20a and the high pressure compression portion 20b is 180 °. That is, the compression processes of the two compression units are in opposite phases.
Refrigerating machine oil 41 is enclosed in the lower part of the hermetic container 13. The refrigerating machine oil 41 is supplied to the low-pressure compression unit 20a and the high-pressure compression unit 20b directly or through a oil supply hole 43 provided in the rotary shaft 2 as shown in FIG. Is done.

  This embodiment is a compressor 1 for an air conditioner using a gas refrigerant R410A, and the ratio of the amount of pressing between the high pressure compressor 20b and the low pressure compressor 20a is set to 0. 0 in accordance with the operating range of the air conditioner. 65 to 0.85. Further, the inner diameters D1 and D2 of the respective cylinders 10a and 10b are set to substantially the same value in order to provide versatility of the processing jig and the measuring device. The outer diameter d2 of the roller 11b of the high pressure compression section 20b is equal to or greater than the outer diameter d1 of the roller 11a of the low pressure compression section 20a, and the height of the cylinder 10b of the high pressure compression section 20b is compressed from the low pressure Ps to the intermediate pressure Pm. In consideration of the reduction in the volume of the gas refrigerant, the height of the cylinder 10a of the low-pressure compression unit 20a is made lower.

The flow of the gas refrigerant which is a working fluid is represented by an arrow in FIG. The low-pressure Ps gas refrigerant is sucked into the low-pressure compressor 20a through the low-pressure side suction pipe 31 and the suction port 25a, and is compressed to the intermediate pressure Pm by the eccentric rotation of the roller 11a. When the pressure in the compression chamber 23a reaches a preset intermediate pressure Pm, the discharge valve 28a opens the discharge port 26a, and the gas refrigerant is discharged into the discharge space 33 communicating with the discharge port 26a.
The gas refrigerant having the intermediate pressure Pm discharged from the discharge port 26a with the discharge valve 28a opened passes through the discharge space 33, the intermediate flow path pipe 30, and the suction port 25b and reaches the compression chamber 23b of the high-pressure compression unit 20b. .

  Next, the gas refrigerant having the intermediate pressure Pm sucked into the high-pressure compressor 20b is compressed to the high pressure Pd by the revolution of the roller 11b. When the pressure in the compression chamber 23b reaches a preset high pressure Pd, the discharge valve 28b opens the discharge port 26b, and the gas refrigerant is discharged from the discharge port 26b to the internal space of the sealed container 13. The gas refrigerant discharged into the hermetic container 13 passes through the gap of the electric motor 14 and is discharged from the discharge pipe 27.

Next, the radial gap of the present invention will be described with reference to FIG. In FIG. 2, the rotation center O of the rotating shaft 2 and the centers of the inner diameters of the cylinders 10a and 10b are made to coincide. As shown in FIG. 2, the inner diameter D1 of the cylinder 10a, the outer diameter d1 of the roller 11a, and the amount of eccentricity e1 from the rotation center O of the rotation shaft 2 at the center of the eccentric portion 5a are solid contact between the cylinder 10a and the roller 11a. In order to avoid the above, a predetermined radial gap δ1 is obtained.
δ1 = D1 / 2−d1 / 2−e1 (1)
The relationship.
Similarly, as shown in FIG. 2, the inner diameter D2 of the cylinder 10b, the outer diameter d2 of the roller 11b, and the eccentric amount e2 from the rotation center O of the rotating shaft 2 at the center of the eccentric portion 5b are the cylinder 10b and the roller 11b. In order to avoid a solid contact, a predetermined radial gap δ2 is obtained.
δ2 = D2 / 2-d2 / 2-e2 (2)
The relationship.

  In the present embodiment, the inner diameters D1 and D2 of the cylinders 10a and 10b constituting the compression portions 20a and 20b are set to the same predetermined value, the heights of the cylinders 10a and 10b are set to predetermined values, respectively, and the ratio of the predetermined pressing amount is set. The outer diameters d1 and d2 of the roller 11a and the roller 11b for realizing are set to respective predetermined values. Next, the radial gap δ1 is set within a range that the component accuracy and assembly accuracy allow, and thereafter the eccentric amounts e1 and e2 are set so as to satisfy the expression (3).

Here, considering that the oil film 42b of the high pressure compressor 20b, which is a phenomenon peculiar to the rotary two-stage compressor, is thicker than the oil film 42a of the low pressure compressor 20a as shown in FIG. From the viewpoint of cost reduction, the cylinders 10a and 10b have the same inner diameter D1 and inner diameter D2, and the outer diameters d1 and d2 of the rollers 11a and 11b are larger than the outer diameter d1 as described above. The eccentric amount e1 and the eccentric amount e2 of the eccentric portions 5a and 5b make the eccentric amount e1 larger than the eccentric amount e2.
Then, the relationship between the radial gap δ1 and the radial gap δ2 was determined from the experimental results of the compressor efficiency shown in FIG.
1 <(δ2 / δ1) <3 (3)
Most preferably, (δ2 / δ1) = 2.

Next, FIG. 3 shows the measurement result of the change in compressor efficiency when the radial gap δ1 is fixed in the range of 5 to 30 μm and the radial gap δ2 is changed. The measurement points are indicated by square plot symbols. Here, assuming that the compressor efficiency when the radial gap δ2 is the same value as the radial gap δ1 (δ2 = δ1) is the reference value 100%, the ratio with respect to the reference value when the radial gap δ1 is fixed and the radial gap δ2 is changed is shown. Show. Here, the compressor efficiency is obtained by dividing the actual input power to the electric motor 14 by the theoretical power required when isentropic compression is performed from the low pressure Ps to the high pressure Pd.
As shown in FIG. 3, when (δ2 / δ1)> 1, the friction efficiency and the oil film reaction force of the high-pressure compression section 20b are reduced, so that the compressor efficiency is improved. When (δ2 / δ1) is further increased, δ2 increases beyond the difference in the oil film thickness of the high-pressure compressor 20b, so that the refrigerant leakage loss of the high-pressure compressor 20b increases and the compressor efficiency decreases. That is, in the range of 1 <(δ2 / δ1) <3, the compressor efficiency can be improved as compared with the conventional rotary two-stage compressor. In particular, when the value of (δ2 / δ1) is approximately 2, the compressor Efficiency is maximized.

Next, the positional relationship between the rotating shaft 2 and the cylinder 10a when assembling the compressor 1 in the embodiment will be described with reference to FIG.
FIG. 4 is a plan view of the low-pressure compression section when the compressor is assembled. In FIG. 4, the reference numerals corresponding to the respective configurations and dimensions of the high-pressure compression unit are shown in parentheses. However, the phase of the compression process is shifted by 180 ° between the low-pressure compressor 20a and the high-pressure compressor 20b, but this relationship is not reflected in FIG.
As shown in FIG. 4, the radial gap between the rollers 11a, 11b and the cylinders 10a, 10b is set to the minimum values Δ1, Δ2 when the angle θ indicated by the clockwise arrow with respect to the circumferential position of the vanes 18a, 18b is 225 °. The rotation center O of the rotary shaft 2 was decentered with respect to the centers of the inner diameters D1 and D2 of the cylinders 10a and 10b. The smaller the minimum values Δ1 and Δ2, the smaller the refrigerant leakage, but the minimum value Δ1, because it depends on the processing accuracy of each component such as the main bearing 9, the sub-bearing 19 and the rotary shaft 2, and the assembly accuracy of each component. Δ2 is 5 to 30 μm.
Although the angle θ is 225 ° in this embodiment, the angle θ may be other than 225 ° as long as the refrigerant is discharged from the compression chambers 23a and 23b.

  As described above, according to the present embodiment, the radius gap δ2 of the high-pressure compression unit 20b is set to the radius of the low-pressure compression unit 20a in response to the oil film of the high-pressure compression unit 20b being thicker than the oil film of the low-pressure compression unit 20a. Since it is larger than the gap δ1 and is within the range of the expression (3), the frictional resistance and the oil film reaction force between the oil film of the roller 11b and the cylinder 10b in the high pressure compression unit 20b are reduced, and the compressor efficiency is reduced. Will improve. That is, not only in the discharge stroke, but also in the suction and compression stroke, the frictional resistance and the oil film reaction force in the high-pressure compression section 20b are reduced to improve the compressor efficiency.

  As shown in FIG. 4, in the actual assembly, the above-mentioned effect is obtained by adjusting the eccentric amount between the rotation center O of the rotating shaft 2 and the centers of the inner diameters D1 and D2 (see FIG. 2) of the cylinders 10a and 10b. Is obtained.

In the present embodiment, the inner diameter D1 and the inner diameter D2 of the cylinders 10a and 10b are set to the same value, and the eccentric amount e1 and eccentricity e2 of the eccentric portions 5a and 5b, and the outer diameter d1 and outer diameter d2 of the rollers 11a and 11b are set. Although it was made to differ between the low pressure compression part 20a and the high pressure compression part 20b, and it was set so that the value of Formula (3) might be satisfy | filled, it is not limited to it.
For example, Equation (3) can also be obtained by making only one of the three parameters of the inner diameter of the cylinder, the outer diameter of the roller, and the amount of eccentricity different between the low pressure compression section 20a and the high pressure compression section 20b. Can be set to meet.
Specifically, the inner diameter D1 and the inner diameter D2 may be the same value, the outer diameter d1 and the outer diameter d2 may be the same value, and the eccentric amount e2 may be smaller than the eccentric amount e1. The inner diameter D1 and the inner diameter D2 may be the same value, the eccentricity e1 and the eccentricity e2 may be the same value, and only the outer diameter d2 may be smaller than the outer diameter d1.

Further, the inner diameter D2 may be larger than the inner diameter D1, the outer diameter d1 and the outer diameter d2 may be the same value, and the eccentricity e1 and the eccentricity e2 may be the same value.
That is, δ1 can be set by changing any one of the inner diameter D1 of the cylinder 10a, the outer diameter d1 of the roller 11a, and the eccentric amount e1 of the eccentric portion 5a by several to several tens of μm. Similarly, δ2 can be set to the cylinder 10b. As long as (δ2 / δ1) satisfies the expression (3), any one of the inner diameter D2, the outer diameter d2 of the roller 11b, and the eccentricity e2 of the eccentric portion 5b can be changed by several to several tens μm. In this case, an effect equivalent to that of the present embodiment can be obtained.

  Further, the height clearance of the high pressure compression section between the end plate portion 9a and the cylinder 10b and between the cylinder 10b and the intermediate partition plate 15 is set between the cylinder 10a and the intermediate partition plate 15, and between the cylinder 10a and the end plate portion 19a. The amount of the refrigerating machine oil 41 that enters the compression chamber 23b through the height clearance of the high-pressure compression section may be controlled by controlling it to be smaller than the height clearance of each low-pressure compression section. That is, the surface finishing of the facing surface between the end plate portion 9a and the cylinder 10b and the facing surface between the cylinder 10b and the intermediate partition plate 15 is performed between the facing surface between the cylinder 10a and the intermediate partition plate 15 and between the cylinder 10a and the end plate portion 19a. The surface finish of the facing surface is improved, and the amount of the refrigerating machine oil 41 entering the high-pressure compression unit 20b is suppressed. As such, the compressor efficiency of the high-pressure compression section is improved by suppressing the amount of intrusion of the refrigerating machine oil 41 through the height clearance of the high-pressure compression section as much as possible and suppressing an increase in the oil film thickness. Can do.

It is a longitudinal cross-sectional view of the rotary two-stage compressor which shows embodiment of this invention. It is a top view of the compression part of this embodiment. It is a figure showing the relationship between ratio (delta2 / delta1) of the radial gap of the compression part for low pressure of the rotary two-stage compressor of this embodiment, and the compression part for high pressure, and a compressor efficiency ratio. It is a figure explaining the adjustment of the radial gap at the time of the assembly of the compression part of this embodiment. It is a schematic diagram which shows the structure of the rotary 2 stage compressor of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary two-stage compressor 2 Rotating shaft 3 Compression mechanism part 5a, 5b Eccentric part 7 Stator 8 Rotor 9 Main bearing 9a End plate part (partition member)
10a, 10b Cylinder 11a, 11b Roller 13 Sealed container 14 Electric motor 15 Intermediate partition plate (partition member)
18a, 18b Vane 19 Sub bearing 19a End plate part (partition member)
20a Low pressure compression section 20b High pressure compression section 23a, 23b Compression chamber 28a, 28b Discharge valve 30 Intermediate flow path pipe

Claims (2)

An electric motor housed in a sealed container, a rotating shaft having two substantially cylindrical eccentric parts and driven by the electric motor, two substantially cylindrical cylinders, and the eccentric part rotating in each cylinder A substantially cylindrical roller that rotates eccentrically, and a plate-shaped vane that partitions the inside of the cylinder, and includes a compression mechanism that sucks in, compresses, and discharges gas.
The compression mechanism section sucks and compresses low-pressure gas from the outside, and compresses the pressure by sucking and compressing the gas compressed by the low-pressure compression section to an intermediate pressure, and once sealed In a rotary two-stage compressor including a high-pressure compressor that discharges into a container,
The inner diameter D2 of the cylinder constituting the high pressure compression section, the outer diameter d2 of the roller, and the roller of the high pressure compression section determined by the eccentric amount e2 of the eccentric section from the rotation center of the rotation shaft. A radial gap δ2 (= D2 / 2-d2 / 2-e2) between the outer peripheral surface and the inner peripheral surface of the cylinder is
The inner diameter D1 of the cylinder constituting the low-pressure compression section, the outer diameter d1 of the roller, and the roller of the low-pressure compression section determined by the eccentricity e1 of the eccentric section from the rotation center of the rotation shaft. A rotary two-stage compressor characterized by being larger than a radial gap δ1 (= D1 / 2−d1 / 2−e1) between an outer peripheral surface and an inner peripheral surface of a cylinder. When the inner diameter D1 of the cylinder of the low pressure compression section and the inner diameter D2 of the cylinder of the high pressure compression section are substantially the same value,
2. The rotary 2 according to claim 1, wherein the relationship between the radial gap δ <b> 1 of the low-pressure compression section and the radial gap δ <b> 2 of the high-pressure compression section is 1 <(δ2 / δ1) <3. Stage compressor.

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