JPH0681786A - Two-stage compression type rotary compressor - Google Patents

Abstract

PURPOSE:To improve the volume efficiency and compression efficiency with a smaller discharge capacity by setting the fitting clearance between the constitution parts in a low stage side compression part smaller than that in a high stage side compression part, as for a compression mechanism part arranged inside a sealed case. CONSTITUTION:A compressor 1 is provided with an electric motor part 13 consisting of a stator 11 and a rotor 12 inside a sealed case 10. Further, at the extension part of a rotary shaft 14 fitted along the axis center part of the rotor 12, a compression mechanism part 15 consisting of the low stage side and high stage side compression parts M and H is arranged. Further, as for both the compression parts M and H, the rotors 23 and 24 of the cylinder chambers 21 and 22 of the cylinders 18 and 19 are arranged in rotatable manner. On the outer peripheral wall of the rotors 23 and 24, blades 25 and 26 are installed. In this constitution, the fitting clearance between the constitution parts in the low stage side compression part M is set smaller than the fitting clearance between the constitution parts of the high stage side compression part H.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stage compression type rotary compressor used in, for example, a refrigeration cycle, and more particularly, to an improved fitting clearance setting structure for constituent parts adapted to the form of the compression mechanism. Regarding

[0002]

2. Description of the Related Art A two-stage compression type rotary compressor is used for a refrigeration cycle in a refrigerator for obtaining a cryogenic temperature range, for example, or a refrigeration cycle having a large compression ratio which is a ratio of a high pressure side pressure to a low pressure side pressure. Used for. This type of compressor is housed in a hermetically sealed case in a state where an electric motor unit and a compression mechanism unit are connected via a rotary shaft.

The compression mechanism section includes a first cylinder and a second cylinder.
, And an intermediate partition plate is provided between these cylinders. Eccentric parts that are 180 ° out of phase with each other are provided in the rotating shaft parts corresponding to the insides of the first and second cylinders, and the rollers are fitted to the respective eccentric parts,
Each cylinder is housed so as to be eccentrically rotatable.

With the rotation of the rotary shaft, however, one of the rollers makes an eccentric rotational movement in the first cylinder, sucks and compresses the refrigerant gas, and discharges it to an intermediate pressure. That is, the low-stage compression section is configured here.

The intermediate pressure gas is eccentrically rotated by the other roller in the second cylinder, sucked and compressed, and discharged at a high pressure. That is, the high-stage compression section is configured here.

[0006]

In a commonly used one-stage compression type rotary compressor, if it is operated at a large compression ratio, the volume efficiency and compression efficiency will be reduced. A two-stage compression type rotary compressor is adopted. The details of this situation are as follows:
It is described in detail in Japanese Patent Publication No. 62-30693.

[0007] However, in the above-mentioned publication, as a technique for reducing the volumetric efficiency and the compression efficiency, only the optimization of the discharge gas cooling or the technique of simplifying the intermediate economizer is disclosed. The technology was not directly related, so it was effectively inadequate.

The present invention has been made in view of the above-mentioned circumstances, and its object is to adapt to the form of the compression mechanism portion when the inside of the closed case is at high pressure and when it is at intermediate pressure. It is an object of the present invention to provide a two-stage compression rotary compressor that can improve volumetric efficiency and compression efficiency with a smaller discharge volume by setting the clearance so as to obtain a large refrigerating capacity.

[0009]

In order to achieve the above object, the first invention is

A sealed case, an electric motor unit, two cylinders simultaneously driven by the electric motor unit, and a compression mechanism unit for eccentrically rotating a roller in the cylinder and partitioning the inside of the cylinder with a blade to suck and compress gas for discharge. Equipped with,

The compression mechanism section is a low-stage compression section for sucking and compressing a low-pressure gas from the outside, and a gas that has been compressed by the low-stage compression section and has been boosted to an intermediate pressure is sucked and compressed to a high pressure. Then, it is composed of a high-stage side compression section that once discharges into the closed case, and makes the pressure inside the closed case a high pressure substantially equal to the high-stage side discharge pressure,

A two-stage compression rotary compression characterized in that the fitting clearance between the components in the low-stage compression section is set smaller than the fitting clearance between the components in the high-stage compression section. It is a machine.

According to a second aspect of the present invention, the compression mechanism section sucks a low-pressure gas from the outside to compress it, raises it to an intermediate pressure, and
The low-stage side compression section that discharges into the closed case and makes the pressure inside the closed case an intermediate pressure approximately equal to the low-stage side discharge pressure, and the intermediate pressure gas discharged from the low-stage side compression section into the closed case It consists of a high-stage side compression part that sucks in, compresses, and raises the pressure,
The fitting clearance between the constituent parts in the high-stage compression section is set to be smaller than the fitting clearance between the constituent parts in the low-stage compression section.
It is a stage compression type rotary compressor.

[0014]

According to the first aspect of the invention, in the compressor in which the pressure in the closed case is set to a high pressure substantially equal to the discharge pressure on the high stage side, the fitting clearance between the constituent parts in the compression unit on the low stage side is
Since it is set to be smaller than the fitting clearance between the components in the high-stage compression section, high-pressure gas in the sealed case can be prevented from leaking into the low-stage compression section where the pressure difference is large, and volume efficiency and compression efficiency can be reduced. Can be connected to the improvement of.

According to the second aspect of the invention, in the compressor in which the pressure inside the closed case is set to an intermediate pressure substantially equal to the discharge pressure on the low stage side, the fitting clearance between the constituent parts in the high stage side compression section is set to the low stage side compression. Since it is set to be smaller than the fitting clearance between the component parts in the section, it is possible to reduce high pressure gas in the high-stage compression section from leaking into the sealed case with a large pressure difference, which leads to improvement in volume efficiency and compression efficiency. To be

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a refrigeration cycle circuit in a refrigerator, for example, for obtaining a cryogenic temperature range, or a refrigeration cycle circuit having a large compression ratio which is a ratio of a high pressure side pressure to a low pressure side pressure.

In the figure, 1 is a two-stage compression rotary compressor described later, 2 is a condenser, 3 is a first capillary tube,
4 is a liquid tank, 5 is a second capillary tube, 6 is a first evaporator, and 7 is a second evaporator, and these are communicated via a refrigerant pipe P so as to constitute a refrigeration cycle.
The liquid tank 4 and the compressor 1 are communicated with each other by an injection pipe 9 having an auxiliary capillary tube 8 in the middle.

As shown in FIG. 1, the two-stage compression type rotary compressor 1 is constructed. In this case, the horizontal type will be described, but the present invention is not limited to this type, and can be naturally adopted as a vertical type compressor.
Reference numeral 10 in the drawing denotes a hermetically sealed case, and an electric motor section 13 including a stator 11 and a rotor 12 is disposed in a substantially central portion of the hermetically sealed case 10. A rotary shaft 14 is fitted along the axial center of the rotor 12, and extends in the horizontal direction along the axial direction of the horizontal type sealed case 10. A compression mechanism section 15 including a low-stage compression section M and a high-stage compression section H is provided in a portion of the rotary shaft 14 extending from the electric motor section 13.

That is, both ends of the portion of the rotary shaft 14 extending from the electric motor portion 13 are rotatably supported by the main bearing 16 and the sub bearing 17, and the main bearing 16 is provided in the first cylinder 1.
8, the auxiliary bearing 17 is attached and fixed to the second cylinder 19, respectively.

Each of the cylinders 18 and 19 is a closed case 10.
The intermediate partition plate 20 is interposed between them and has a diameter fitted to the inner peripheral wall of the cylinder. And a second cylinder chamber 22 are formed.

An eccentric portion is integrally formed with the rotary shaft 14 portion corresponding to the position of each cylinder chamber 21, 22, and the rollers 23, 24 are rotatably fitted therein. Each of the eccentric portions is provided so as to be displaced by 180 ° so that the rotation shaft 14 can be balanced in rotation.

On the outer peripheral walls of the rollers 23 and 24, the blades 2 provided on the cylinders 18 and 19 respectively.
5 and 26 are elastically in contact with each other so as to partition the insides of the respective cylinder chambers 21 and 22 into a high pressure chamber and a low pressure chamber.

The first cylinder chamber 21 formed in the low-stage compression section M is communicated with a low-stage suction pipe 27 penetrating the left end surface of the hermetically sealed case 10 in the drawing. 18 to the discharge valve 28a and the discharge passage 28
An intermediate pressure discharge pipe 28 that protrudes to the outside of the closed case 10 is communicated via b. The low-stage suction pipe 27 corresponds to the refrigerant pipe P that communicates the second evaporator 7 and the compressor 1 with reference to FIG.

In the second cylinder chamber 22 formed in the high-stage compression section H, the intermediate pressure discharge pipe 28 is provided with the sealed case 10.
It is communicated from the outside via the suction passage 19a of the second cylinder 19. Further, the injection pipe 9 passing through the left end portion of the closed case 10 in the drawing is communicated.

The second cylinder 19 is provided with a communication passage (not shown) which communicates with the first cylinder 18 via the flange portion of the main bearing 16, and the second cylinder chamber 22.
Muffler 30 provided on the main bearing 16 for the gas compressed by
It is designed to discharge inside. The gas discharged into the muffler 30 is discharged into the closed case 10 through the opening 30a of the muffler 30 and is filled therewith.

In the figure, a high pressure discharge pipe 33 is connected to the right side surface of the closed case 10 for guiding the gas filled in the closed case 10 to the outside. The discharge pipe 33 also corresponds to the refrigerant pipe P that communicates the compressor 1 and the condenser 2 with each other, which is described above with reference to FIG. The auxiliary bearing 17 is provided with a pump chamber 31 for temporarily storing lubricating oil from the blade chamber 26a via an oil supply pipe. Figure 3
As shown in (A) and (B), the fitting clearances of the components in the low-stage compression section M and the high-stage compression section H are set.

More specifically, C _L a is a side clearance between the inner diameters of the first and second cylinder chambers 21 and 22 and the outer diameters of the rollers 23 and 24. Setting of the side clearance C _L a, as shown in FIG, theta> 180 °
Position. C _L b is the first and second cylinder 1
The height clearance between the heights of 8 and 19 and the heights of the rollers 23 and 24. C _L c is the cylinder blade groove 25a,
26a is a side clearance between the width of the blade 25 and the thickness of the blade 26. C _L d is the height of the cylinders 18 and 19,
It is the height clearance with the height of the blades 25, 26.
Set the fitting clearances in the low-stage compression section M to C _L a1,

C _L b1, C _L c1, C _L d1 and the respective fitting clearance settings in the high-stage compression section H are C _L a2, C _L b2, C _L c2, C _L d2.
The fitting clearance settings corresponding to the respective compression portions M and H must hold the following relationship. C _L a1 ≤ C _L a2 C _L b1 ≤ C _L b2 C _L c1 ≤ C _L c2 C _L d1 ≤ C _L d2 Next, the two-stage compression rotary compressor 1 configured as described above and the refrigeration The cycle action will be described.

The electric motor section 13 drives the rotary shaft 14 to rotate,
The low-pressure refrigerant gas is guided to the compressor 1 from the second evaporator 7.
The gas is transferred to the low pressure side compression section M via the low pressure side suction pipe 27.
It is sucked into the first cylinder chamber 21 that is formed and is shown below.
Compressed to the intermediate pressure Pm state. Pm = (NP_1s・ P_2d)^1/2  Note that P_1s: Suction pressure of the lower compression section M, P_2d: High side
Discharge pressure of the compression section H.

The refrigerant gas having the intermediate pressure Pm is introduced into the second cylinder chamber 22 formed in the high-stage compression section H, where it is compressed to the high pressure P _2d state, and the inside of the closed case 10 is closed. Is discharged.

The high-pressure refrigerant gas is filled in the closed case 10 and is sequentially discharged from the high-pressure discharge pipe 33. Then, it is guided to the condenser 2 to be condensed, is converted into a liquid refrigerant, is guided to the first capillary tube 3, is decompressed by one stage, and is guided to the second capillary tube 5 via the liquid tank 4, and is decompressed in the second stage. The pressure is reduced.

Furthermore, the first evaporator 6 and the second evaporator 7 are sequentially guided to evaporate, and heat is exchanged with the heat exchange air introduced into the first evaporator 6 and the second evaporator 7, thereby converting into cold air of extremely low temperature. The second-stage evaporated refrigerant is sucked into the compressor 1 again, and circulates in the above cycle.

On the other hand, the closed case 10 is filled with the high-temperature and high-pressure gas that is compressed and discharged in the high-stage side compression section H, and the closed case 10 is always under the high-temperature and high-pressure atmosphere. Therefore, the outer peripheral surface of the high-stage side compression portion H and the outer peripheral surface of the low-stage side compression portion M are also exposed to this high-temperature high-pressure gas.

Pressure f in the cylinder chamber 21 of the low-stage compression section M
The relationship shown below is always maintained between (PL) and the closed case internal pressure P _2d that is approximately equal to the discharge pressure of the high-stage compression section H. _{P 2d - f (PL) ≧} P 2d - Pm >> 0 Therefore, the pressure difference between the high low-stage compressing section M in the cylinder chamber 21, the hot high pressure gas tries to leak penetration from the surroundings.

However, in the compressor 1,
As described above, since the fitting clearance setting value in each part of the low-stage compression section M is set to be smaller than the fitting clearance setting value in each part of the high-stage compression section H, leakage into the cylinder chamber 21 occurs. The amount of invading gas can be reduced, and the volume efficiency and compression efficiency are good.

In the above embodiment, the case where the pressure inside the closed case is set to high pressure has been described, but as shown in FIG. 4, the two-stage compression type rotary compressor 10 in which the inside pressure of the closed case is set to the intermediate pressure.
You may use 0. In the figure, 110 is a closed case,
The stator 11 is provided at a substantially central portion in the closed case 110.
1 and a rotor 112 are provided with an electric motor unit 113. A rotary shaft 114 is fitted along the axial center of the rotor 112, which is a horizontal type of the closed case 11 described above.
It extends horizontally along the 0 axis direction. And
A compression mechanism unit 115 including a low-stage compression unit Ma and a high-stage compression unit Ha is provided in a portion of the rotating shaft 114 extending from the electric motor unit 113.

Both ends of the portion of the rotary shaft 114 extending from the electric motor portion 113 have a main bearing 116 and a sub bearing 117.
Is rotatably supported by the main bearing 116 in the first cylinder 118, the auxiliary bearing 117 in the second cylinder 119,
Each is fixedly attached.

An intermediate partition plate 120 is provided between each of the cylinders 118 and 119, and together with the main bearing 116 and the sub bearing 117, a first cylinder chamber 121 which is a space in each of the cylinders 118 and 119, The second cylinder chamber 122 is formed.

An eccentric portion is integrally formed with the rotating shaft 114 portion corresponding to the positions of the cylinder chambers 121 and 122, and the rollers 123 and 124 are rotatably fitted therein. The eccentric portions are provided so as to be eccentrically displaced by 180 ° so that the rotation shaft 114 can be rotationally balanced.

As shown only in FIGS. 5A and 5B, the blades 125 and 12 provided on the cylinders 118 and 119 are provided on the outer peripheral walls of the rollers 123 and 124, respectively.
6 are in elastic contact with each other, and each cylinder chamber 12
The inside of 1,122 is divided into a high pressure chamber and a low pressure chamber.

As shown in FIG. 4 again, the low-stage compression section Ma
In the cylinder chamber 121 of the low-stage side suction pipe 12 that penetrates the first cylinder 118 and projects to the outside of the closed case 110.
7 are in communication. The suction pipe 127 is provided with an accumulator 128 in the middle and corresponds to the refrigerant pipe P communicating with the second evaporator 7.

Further, in the middle part of the suction pipe 127, the right side in the figure of the closed case 110 is penetrated, the opening end is projected to the inner bottom part of the case 110, and the oil return provided with the auxiliary capillary tube 129 in the middle part. The pipe 130 is in communication.

A low-stage discharge section 131 is provided on the flange of the main bearing 116, and a low-stage muffler 132 is provided.
Covered in. The gas compressed in the first cylinder chamber 121 is discharged into the muffler 132 from the low-stage discharge portion 131, and further through a not-illustrated discharge hole provided here and a gap between the muffler 132 and the main bearing 116. It is guided into the closed case 110 and fills the space.

A high-stage suction pipe 133 penetrating the second cylinder 119 and protruding to the outside of the hermetically sealed case 110 communicates with the second cylinder chamber 122 formed in the high-stage compression section Ha. The suction pipe 133 is provided with a pre-cooling heat exchanger 134 in the middle thereof and communicates with an intermediate pressure gas discharge pipe 135 which penetrates the right end portion of the closed case 110 in the drawing.

The secondary bearing 117 has a high-stage discharge valve portion 136.
Is provided and is covered with the high-stage side discharge muffler 137 provided here. Further, a high-stage discharge pipe 138 penetrating the first cylinder 118 and protruding to the outside of the closed case 110 is connected so as to communicate with the inside of the muffler 137.

Therefore, the gas compressed in the second cylinder chamber 122 is once discharged into the muffler 137, and further from the high-stage side discharge pipe 138 to the closed case 110.
It is designed to be guided to the condenser 2, which is the outside. Figure 5
As shown in (A) and (B), the fitting clearances of the components in the low-stage compression section Ma and the high-stage compression section Ha are set.

More specifically, C _L f is the inner diameter of the first and second cylinder chambers 121 and 122, the roller 123,
124 is the side clearance with the outer diameter. As shown in the figure, the setting of the side clearance C _L f is θ>
The position is 180 °. _CL g is the height clearance between the height of the first and second cylinders 118 and 119 and the height of the rollers 123 and 124. C _L h is the width of the cylinder blade grooves 125a, 126a and the width of the blades 125, 12
It is a side clearance with 6 thicknesses. C _L i is the height clearance between the height of the cylinders 118 and 119 and the height of the blades 125 and 126.

The fitting clearances in the low-stage compression section Ma are set to C _L f1, C _L g1, and C _L h, respectively.
1, C _L i1, and the respective fitting clearance settings in the high-stage compression section Ha are C _L f2, C _L g2, C
Let _L h2 and C _L i2. In the compression parts Ma and Ha of each other,
The corresponding mating clearance settings must hold the relationship shown below. Refrigeration cycle circuit of _{C L f1 ≧ C L f2 C} L g1 ≧ C L g2 C L h1 ≧ C L h2 C L i1 ≧ C L i2 refrigerator using the compressor, as shown above in FIG. 2 The same may be used, and here, the same drawing is applied and a new description is omitted. Next, the operation of the two-stage compression rotary compressor 100 thus configured will be described.

The low-pressure refrigerant gas is guided from the second evaporator 7 to the compressor 100 and is sucked into the first cylinder chamber 118 formed in the low-pressure side compression section Ma via the low-pressure side suction pipe 127. At the same time, some of the lubricating oil that collects at the bottom of the closed case 110 also merges and is guided to the cylinder chamber 118.

The refrigerant gas sucked into the cylinder chamber 118 is compressed by the eccentric rotation of the rotor 123,
The pressure is increased to an intermediate pressure, and the lubricating oil mixed therein is discharged from the discharge portion 131 into the closed case 110.

By the way, the internal volume of the sealed case 110 is
Since it is sufficiently large compared to the medium pressure gas volume, the gas flow velocity slows down significantly here. Since the discharge temperature is also lower than that of a normal one-stage compression type compressor, the performance of separating the fluid gas from the lubricating oil is high, and the lubricating oil is reliably separated in this region.

The gas thus compressed to the intermediate pressure and filling the closed case 110 is the intermediate pressure gas discharge pipe 135.
Is temporarily guided to the outside of the closed case 110, precooled by the precooling heat exchanger 134, and sucked into the second cylinder chamber 122 formed in the high pressure side compression portion Ha from the high pressure side suction pipe 133.

In the cylinder chamber 122, the gas is compressed to the final discharge pressure and then discharged to the high-stage discharge pipe 138, which has the same refrigerating cycle function as described above with reference to FIG.

In this compressor 100, since the refrigerant gas is compressed as described above, the internal pressure f (PH) of the cylinder chamber 122 of the high-stage side compression section Ha and the closed case 1
The intermediate pressure Pn, which is the internal pressure of 10, is always in the relationship of f (PH) -Pn≥0. Incidentally, the intermediate pressure Pn = (P _1s · P _2d )
^1/2 , P _1s : suction pressure of the low-stage compression section Ma, P _2d : discharge pressure of the high-stage compression section Ha. Therefore, the high-pressure gas leaks from the cylinder chamber 122 of the high-stage compression section Ha into the closed case 110.

However, in the compressor 100, as described above, the fitting clearance set value in each part of the high-stage compression section Ha is set to be larger than the fitting clearance set value in each part of the low-stage compression section Ma. Since it is also small, the amount of leak invading gas can be reduced, and the volume efficiency and compression efficiency are good.

[0057]

As described above, the first aspect of the present invention is a high-pressure type compressor in a hermetic case, in which high-pressure gas in the hermetic case attempts to leak into the cylinder chamber of the low-pressure side compression section. Since the fitting clearance between the component parts in the stage compression section is set smaller than the fitting clearance between the component parts in the high stage compression section, the volume efficiency and compression efficiency are improved with a smaller discharge volume. It has the effect of obtaining a large refrigerating capacity.

According to the second aspect of the present invention, the compressor is an intermediate pressure type compressor in a closed case, and high pressure gas tries to leak into the closed case from the cylinder chamber of the high pressure side compression section. Since the fitting clearance between the components is set smaller than the fitting clearance between the components in the low-stage compression section, the volumetric efficiency and compression efficiency are improved with a smaller discharge volume to obtain a large refrigeration capacity. The effect is achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a two-stage compression rotary compressor showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle circuit including a compressor according to the first embodiment.

FIG. 3A is a plan view of the compression mechanism unit for explaining clearance setting of the compression mechanism unit of the embodiment. (B) is the longitudinal cross-sectional view.

FIG. 4 is a vertical sectional view of a two-stage compression rotary compressor showing another embodiment of the present invention.

FIG. 5A is a plan view of the compression mechanism unit for explaining clearance setting of the compression mechanism unit of the embodiment. (B) is the longitudinal cross-sectional view.

[Explanation of symbols]

1,110 ... Hermetically sealed case, 3,113 ... Motor part, 1
8, 118 ... First cylinder, 19, 119 ... Second cylinder, 15, 115 ... Compression mechanism part, M, Ma ... Low stage side compression part, H, Ha ... High stage side compression part.

Claims (2)

[Claims] 1. A hermetically sealed case, an electric motor unit housed in the hermetically sealed case, and two cylinders simultaneously driven by the electric motor unit, wherein the rollers are eccentrically rotated in each cylinder and the cylinder is provided by a blade. A compression mechanism section that divides the inside and sucks and compresses gas and discharges it, wherein the compression mechanism section sucks and compresses low-pressure gas from the outside, and a low-stage compression section. It is compressed by, sucks in the gas that has been boosted to an intermediate pressure, compresses it, increases the pressure, and once discharges it into the sealed case.
It consists of a high-stage compression section that makes the internal pressure of the closed case a high pressure that is approximately equal to the high-stage discharge pressure, and the fitting clearance between the components in the low-stage compression section is equal to the high-stage compression section. A two-stage compression rotary compressor characterized in that the clearance is set smaller than the fitting clearance between the components. 2. A hermetically sealed case, an electric motor section housed in the hermetically sealed case, and two cylinders simultaneously driven by the electric motor section, wherein the rollers are eccentrically rotated in each cylinder and the cylinder is provided by a blade. A compression mechanism section for partitioning the inside, sucking in and compressing the gas, and discharging the gas, wherein the compression mechanism section sucks and compresses a low-pressure gas from the outside, raises the pressure to an intermediate pressure, and once It is discharged inside and the low pressure side compression section that makes the pressure inside the closed case an intermediate pressure approximately equal to the low pressure side discharge pressure and the intermediate pressure gas discharged into the closed case from this low pressure side compression section It is composed of a high-stage compression section that compresses and increases the pressure, and the fitting clearance between the constituent parts in the high-stage compression section is greater than the fitting clearance between the constituent parts in the low-stage compression section. 2-stage compression type rotary compressor, characterized in that the fence set.