JPH094584A - Compressor and refrigeration cycle - Google Patents

Abstract

PURPOSE: To reduce the manufacturing cost and to improve the efficiency by injecting the refrigerant of intermediate pressure in a space in the suction stroke. CONSTITUTION: A suction port 18 of intermediate pressure provided on a housing 10, a housing port 18a to be communicated therewith, an end plate part of a terminal position of a movable scroll 14, and a scroll port 18b to be communicated with the space 23 through the end plate part 14b are provided. The scroll port 18b is revolved, and the ports are overlapped to communicate the space 23 in the suction stroke with the suction port 18 of intermediate pressure. The refrigerant of intermediate pressure is injected in the space 23 in the suction stroke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor, which is suitable for use as a compressor for a two-stage expansion refrigeration cycle.

[0002]

2. Description of the Related Art Conventionally, a well-known two-stage expansion refrigeration cycle has been proposed as a means for improving the efficiency of the refrigeration cycle. In this two-stage expansion refrigeration cycle, a gas refrigerant (intermediate pressure refrigerant) having an intermediate pressure that does not directly contribute to cooling after passing through the first expansion valve is taken out by a gas-liquid separator and the intermediate pressure refrigerant is compressed again. This reduces the work of the compressor and improves the efficiency of the refrigeration cycle.

Conventionally, two compressors (two-stage compression type) have been required to carry out this two-stage expansion refrigeration cycle. Therefore, compared with a normal refrigeration cycle with one compressor, compression is performed. There has been a problem that the manufacturing cost of the refrigeration cycle rises by the amount of one additional machine, and the manufacturing cost is high (the cost-effectiveness is small) for improving the efficiency of the refrigeration cycle.

[0004]

In order to solve this problem, a vane type two-stage compressor has been proposed as described in Japanese Patent Laid-Open No. 145915/1975. However, there is a problem in that the suction and discharge passages become complicated and sufficient cost effectiveness cannot be obtained. As another solution, an invention has been proposed in which a single compressor performs a two-stage expansion refrigeration cycle, as described in Japanese Patent Laid-Open No. 2-96165. However, according to the present invention, since the intermediate pressure refrigerant is injected into the space during the compression stroke of the compressor, the pressure (expanding force) of the intermediate pressure refrigerant and the force of the compressor to be compressed are used. Oppose. Therefore, there is a problem that the force required for compression increases, and the effect of improving the efficiency of the refrigeration cycle is small as compared with the above-described two-stage compression type. Furthermore, since the intermediate pressure refrigerant is introduced into the space during the compression stroke, a check valve is required in the refrigerant passage,
There is a problem that sufficient cost effectiveness cannot be obtained.

In view of the above points, an object of the present invention is to reduce the manufacturing cost and provide a highly efficient refrigeration cycle.

[0006]

In order to achieve the above object, the present invention uses the following technical means. In the invention according to claim 1, the suction port (17) for sucking the low-pressure medium.
A compression mechanism (14, 16) for compressing the low pressure medium sucked from the suction port (17), and a discharge port (19) for discharging the high pressure medium compressed by the compression mechanism (14, 16). In the compressor, the intermediate pressure medium having an intermediate pressure between the low pressure medium and the high pressure medium is transferred to the space (22) during the suction stroke of the compression mechanism (14, 16).
Intermediate pressure injection port (18) for injection
A compressor characterized by having.

According to a second aspect of the present invention, in the compressor according to the first aspect, the pressure in the space (22) during the suction stroke in which the intermediate pressure medium is injected becomes equal to that of the low pressure medium. The compressor is characterized in that, at this time, the low-pressure medium starts to be sucked into the space (22) during the suction stroke. In the invention according to claim 3, a movable scroll (14) comprising a spiral scroll (14a) and an end plate portion (14b) integrally formed with the scroll, and a spiral scroll (1
6a) a fixed scroll (16), a suction port (17) for sucking a low pressure medium, and a discharge port (19) for discharging a high pressure medium compressed by the revolution of the movable scroll (14). In a mold compressor, an intermediate pressure medium having an intermediate pressure between the low pressure medium and the high pressure medium is introduced into a space (22) formed by the movable scroll (14) and the fixed scroll (16) during a suction stroke. A sroll type compressor having an intermediate pressure suction port (18) for injection.

According to a fourth aspect of the present invention, in the sroll type compressor according to the third aspect, the movable scroll (14) and a housing that is coupled to the fixed scroll (16) to form a closed space. Is provided at a predetermined portion of the scroll end portion (14c) of the
A scroll port (18b) penetrating through b) and a housing port (18) provided at a predetermined portion of the housing (10) and communicating with the intermediate pressure suction port (18).
a), the orbiting scroll (14) is revolvably arranged in a closed space formed by the fixed scroll (16) and the housing (10), and the orbiting scroll (14) is provided. ), The scroll port (18b) and the housing port (18a) are configured to overlap each other, and when the two ports overlap each other, the space ( 22), and the intermediate pressure suction port (18) is configured to communicate with each other, a sroll type compressor characterized in that.

According to a fifth aspect of the present invention, the compressor according to any one of the first to fourth aspects and a condenser that serves as a heat radiating means for the compressed refrigerant discharged from the discharge port (19) of the compressor. (2), a first pressure reducer (3) for reducing the pressure of the refrigerant condensed in the condenser (2), and a refrigerant passing through the first pressure reducer (3) are separated into a liquid refrigerant and a gas refrigerant. A gas-liquid separator (4), a second pressure reducer (5) for reducing the pressure of the liquid refrigerant that has passed through the gas-liquid separator (4), and a low-temperature low-pressure refrigerant reduced in pressure by the second pressure reducer (5). An evaporator (6) for cooling, a pipe for guiding the gas refrigerant separated by the gas-liquid separator (4) to an intermediate pressure suction port (18) of the compressor, and vaporization by the evaporator (6). Two-stage expansion, characterized in that it comprises a pipe for guiding the gaseous refrigerant to the suction port (17) of the compressor. Freeze cycle.

The reference numerals in parentheses of the above means indicate the correspondence with the concrete means described in the embodiments described later.

[0011]

According to the invention described in claims 1 to 5, the two-stage expansion refrigeration cycle can be carried out by one compressor by injecting the intermediate pressure medium into the space during the suction stroke. Therefore, the two-stage expansion refrigeration cycle can be implemented at a lower cost than the two-stage expansion refrigeration cycle performed using two compressors. Therefore,
The efficiency of the refrigeration cycle can be improved at low cost.

Further, since the intermediate pressure medium having the intermediate pressure between the low pressure medium and the high pressure medium can be injected from the intermediate pressure suction port into the space in the suction stroke of the compression mechanism, the pressure of the intermediate pressure medium is increased. (Expanding force) overlaps with the direction of the force that expands the space during the suction stroke. Therefore, the pressure of the intermediate pressure refrigerant becomes a force for expanding the space during the suction stroke (internal energy is converted into mechanical energy), so the intermediate pressure medium is injected into the space during the compression stroke. Compared with the two-stage expansion cycle (the force required for compression increases), the power consumption of the compressor can be saved. As a result, the efficiency of the refrigeration cycle can be improved.

According to the second aspect of the present invention, when the pressure in the space during the suction stroke in which the intermediate pressure medium is injected becomes equal to that of the low pressure medium, the low pressure medium is sucked into the space during the suction stroke. The intermediate pressure medium can then be expanded until the pressure in the space equals the pressure of the low pressure medium. Therefore, the pressure (internal energy) of the intermediate pressure medium can be effectively converted into mechanical energy that expands the space during the suction stroke without causing an unnecessary force that causes the low pressure medium to flow backward. As a result, the power consumption of the compressor can be further saved.

Further, since the low-pressure medium does not flow back, a check valve or other backflow prevention mechanism need not be provided. Therefore, the two-stage expansion refrigeration cycle can be implemented at a lower cost. According to the invention described in claim 4, the intermediate pressure suction is performed by utilizing the overlapping state of the housing port which is provided in the housing of the scroll compressor and does not move, and the scroll port which is provided in the movable scroll and revolves. Since the communication state from the port to the space during the intake stroke can be controlled, the injection into the space during the intake stroke can be controlled without newly providing control means such as a control valve. Therefore, the two-stage expansion refrigeration cycle can be implemented at a lower cost.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a two-stage expansion refrigeration cycle according to this embodiment. The two-stage expansion refrigeration cycle shown in FIG. 1 will be described below, and then the compressor used in the two-stage expansion refrigeration cycle will be described in detail.

Reference numeral 1 denotes a compressor for compressing a refrigerant, which is driven by a driving device (vehicle engine in this embodiment) not shown, and the compressor 1 has a predetermined pressure (in this embodiment, 1. The gas refrigerant compressed up to 6 MPa flows into the condenser 2 which is a heat radiating means. The refrigerant that has taken away the condensation heat in the condenser 2 and condensed (liquefied) flows into the first expansion valve (first pressure reducer) 3 that serves as a pressure reducer for the liquid refrigerant, and has an intermediate pressure (0.8 MPa in the present embodiment). ), And becomes a wet refrigerant of two phases of gas and liquid. Then, the moist refrigerant is separated by the gas-liquid separator 4 which is a separator between the liquid refrigerant and the gas refrigerant, and the gas refrigerant (intermediate pressure) is a pipe (not shown) in the space during the suction stroke of the compressor 1. Is injected through.

Further, the liquid refrigerant flows into the second expansion valve (second pressure reducer) 5 and is further reduced in pressure (0.3 M in this embodiment).
Pa) to form a low-temperature low-pressure atomized (liquid) refrigerant.
Then, the atomized refrigerant flows into the evaporator 6 serving as a cooling means, takes heat of vaporization, vaporizes and cools. Then, the gas refrigerant is compressed by the compressor 1 together with the gas refrigerant injected into the space during the suction stroke, and flows into the condenser 2 again to complete one cycle.

Next, the structure of the compressor 1 will be described with reference to FIGS.
Will be described using. The compressor 1 shown in FIG. 2 is a well-known scroll type compressor (hereinafter, simply referred to as a compressor) including a spiral scroll and a fixed scroll. 1
Reference numeral 0 is a housing of the compressor 1, and a bearing 12 for rotatably supporting the crankshaft 11 is arranged at substantially the center of the housing 10. A crank pin 13 that forms a crank mechanism is formed at an axial end of the crank shaft 11 at a position eccentric from the shaft center.

Further, the housing 1 on the crankpin 13 side
The movable scroll 14 having a spiral scroll 14a is arranged at the zero end. A bearing 15 is press-fitted in the center of the movable scroll 14, and the movable scroll 14 is press-fitted in the crank pin 13 via the bearing 15. Reference numeral 16 is a fixed scroll having a scroll 16a, and the fixed scroll 16 is assembled to the housing 10 by a bolt (not shown).

Further, as shown in FIG. 3, the housing 10
The side face 10a of the suction port 17 is provided with a suction port 17 through which the low-pressure refrigerant vaporized in the evaporator 6 is sucked.
Are always in communication with the space 24 formed by the movable scroll 14 and the fixed scroll 16. And side 1
An intermediate-pressure suction port 18 for injecting the intermediate-pressure gas refrigerant separated by the gas-liquid separator 4 into the space during the suction stroke is provided at the center of 0a. Further, an opening 19 for discharging the refrigerant compressed by the revolution of the movable scroll 14 is opened at the center of the fixed scroll 16, and the opening 19 is provided in the compressor 1 provided in the fixed scroll 16. Is connected to a discharge port 20 for discharging the refrigerant.

As shown in FIG. 2, the housing 10 is provided with a housing port 18a which communicates with a portion corresponding to the end portion 14c (see FIG. 3) of the scroll 14a to the intermediate pressure suction port 18. A scroll port 18b penetrating the end plate portion 14b is provided on the end plate portion 14b of the terminal end portion 14c of the scroll 14a. The arrangement positions of both ports will be described in the following description of the operation.

Incidentally, as shown in FIG. 3, the cross-sectional shape of both ports is formed into a substantially oval shape in order to increase the cross-sectional area and reduce the suction resistance. Further, when the movable scroll 14 revolves, a contact point with the fixed scroll 16 is generated so that a space into which the intermediate pressure refrigerant is injected is formed, and the end portion 14c of the scroll 14a,
The fixed scroll in the vicinity thereof is formed in a substantially arc shape.

Next, the operation of the compressor 1 will be described. A characteristic of the operation of the compressor 1 is to inject the intermediate pressure refrigerant into a space formed by the movable scroll 14 and the fixed scroll 16 (hereinafter, simply referred to as a space) at the beginning of the suction stroke. . So, below,
The above-mentioned features will be described with reference to FIGS. 4 to 9 based on a time-series change of the space formed by the end portion 14c of the movable scroll 14.

1. Space formation start (see FIGS. 4 and 9) A part of the end portion 14c of the scroll 14a and a part of the fixed scroll 16 make contact as shown in FIG. 4 to form a first contact point 21. At this time, the housing port 18a
(The position indicated by the solid line in FIG. 9) and the scroll port 18b (see FIG. 9).
(State of the two-dot chain line A) does not overlap yet, and there is substantially no space during the suction stroke (zero volume), so that the intermediate pressure refrigerant cannot be injected.

2. Start of injection of intermediate pressure refrigerant (see FIGS. 5 and 9) The orbit of the orbiting scroll 14 proceeds from the start of space formation described above, and a new contact point 22 is formed in addition to the contact point 21 as shown in FIG. . Then, the contact points 21, 22 and both scrolls form a space 23 during the suction stroke. Further, at this time, since both ports are arranged so that the housing port 18a and the scroll port 18b (state of the two-dot chain line B in FIG. 9) start to overlap, the intermediate pressure refrigerant in the space 23 Start injection.

3. The injection of the intermediate pressure refrigerant is completed (see FIGS. 6 and 9).
Moves outward along the wall surface of the fixed scroll 16 and the contact point 22 moves toward the center thereof along the fixed scroll. Along with this, the volume of the space 23 expands, and the pressure of the intermediate-pressure refrigerant injected into the space 23 decreases. Then, when the orbit of the movable scroll 14 further progresses and the space 23 becomes equal to a predetermined volume, the overlap between the housing port 18a and the scroll port 18b (the state indicated by the chain double-dashed line C in FIG. 9) is completed. Since both ports are arranged, the injection of the intermediate pressure refrigerant is completed.

4. Expansion of the intermediate pressure refrigerant (see FIG. 10) After this, the revolution of the orbiting scroll 14 further progresses, and the contact points 21 and 22 move respectively. Since the communication between the housing port 18a and the scroll port 18b has already been cut off, the volume of the space 23 increases with no refrigerant flowing in and out. In this process, the refrigerant already injected into the space 23 expands in the space 23, gradually lowers its pressure, and approaches the pressure of the low-pressure refrigerant.

5. Start suction of low-pressure refrigerant (see FIGS. 7 and 9) Then, the revolution of the movable scroll 14 further progresses, the contact point 21 finally separates from the wall surface of the fixed scroll 16, and the space 23 communicates with the outer space 24 of the movable scroll 14. To do. Since the pressure in the space 23 has already dropped to the pressure equal to that of the low-pressure refrigerant, the low-pressure refrigerant filling the outer space 24 begins to be sucked into the space 23. Incidentally, the scroll port 18b is in a non-overlapping state as indicated by the chain double-dashed line D in FIG.

6. Completion of suction of low-pressure refrigerant (see FIGS. 8 and 9) Then, the revolution of the orbiting scroll 14 further progresses, expansion of the space 23 ends, and the suction stroke of low-pressure refrigerant ends at the same time. Incidentally, the scroll port 18b is in a non-overlapping state as indicated by the chain double-dashed line E in FIG.

Thereafter, the space 23 shifts to the compression process.
The compression stroke of the space 23 is the same as that of a well-known scroll compressor. (The space 23a in FIGS. 4 to 8 represents the space 23 after the transition to the compression stroke.) Next, the characteristics of this embodiment will be described. Space 23 during the inhalation process
Since the two-stage expansion refrigeration cycle can be carried out with one compressor 1 by injecting the intermediate pressure refrigerant into the compressor, it is cheaper than the two-stage expansion refrigeration cycle carried out using two compressors. A two-stage expansion refrigeration cycle can be carried out. Therefore, the efficiency of the refrigeration cycle can be improved at low cost.

Further, since the intermediate pressure refrigerant having the intermediate pressure between the low pressure medium and the high pressure refrigerant is injected from the intermediate pressure suction port 18 into the space during the suction stroke, the pressure (expanding) of the intermediate pressure refrigerant is attempted. Force) is the force to expand the space 23 during the suction stroke. Therefore, the pressure of the intermediate pressure refrigerant expands the space 23 during the suction stroke (internal energy is converted into mechanical energy), so that the intermediate pressure refrigerant is injected into the space during the compression stroke. The power saving of the compressor 1 can be achieved as compared with the stage expansion cycle (the force required for compression increases). As a result, the efficiency of the refrigeration cycle can be improved.

Further, when the pressure in the space 23 during the suction stroke, in which the intermediate pressure refrigerant is injected, becomes equal to the low pressure refrigerant, the low pressure refrigerant begins to be sucked into the space 23 during the suction stroke. The intermediate-pressure refrigerant can be expanded until the pressure of is equal to the pressure of the low-pressure refrigerant.
Therefore, the pressure (internal energy) of the intermediate pressure refrigerant can be effectively converted into mechanical energy that expands the space 23 during the suction stroke without an unnecessary force that causes the low pressure refrigerant to flow backward. As a result, the power consumption of the compressor 1 can be further saved.

Further, since the low-pressure refrigerant does not flow backward, it is not necessary to provide a backflow prevention mechanism such as a check valve. Therefore, the two-stage expansion refrigeration cycle can be implemented at a lower cost. Further, by utilizing the overlapping state of the housing port 18a provided in the housing 10 and not moving and the scroll port 18b provided in the fixed scroll 16 and revolving, the intermediate pressure suction port 18 to the space 23 in the suction stroke. Since it is possible to control the communication state of, the injection of the intermediate pressure refrigerant can be controlled without newly providing a control means such as a control valve. Therefore, the two-stage expansion refrigeration cycle can be implemented at a lower cost.

The compressor according to the present invention is not limited to the scroll type compressor, but can be applied to vane type, swash plate type, rotor type and other compressors. The timing of injecting the intermediate pressure refrigerant is not limited to the initial stroke of the suction stroke, and may be any timing before the compression stroke. Further, the pressure of the intermediate refrigerant does not have to be intermediate (average) between the high pressure refrigerant and the low pressure refrigerant, and may be between the two pressures.

Further, the sectional shapes of the housing port 18a and the scroll port 18b are not limited to the substantially elliptical shape, but may be other shapes such as a circular shape and a polygonal shape. Further, the drive device that drives the compressor is not limited to the vehicle engine, and an electric motor such as a motor may be used.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a two-stage expansion refrigeration cycle according to the present invention.

FIG. 2 is a cross-sectional view (BB of FIG. 3) of the compressor 1.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a cross-sectional view showing the start of formation of a space 23 in FIG.

5 is a cross-sectional view showing the start of intermediate-pressure refrigerant injection in FIG.

6 is a cross-sectional view showing the end of intermediate-pressure refrigerant injection in FIG.

FIG. 7 is a cross-sectional view showing the start of suction of low-pressure refrigerant in FIG.

8 is a cross-sectional view showing the end of suction of low-pressure refrigerant in FIG.

FIG. 9: Housing port 18a and scroll port 1
It is an enlarged view which shows the relative position with 8b.

FIG. 10 is a cross-sectional view showing the expansion process of the refrigerant in the space 23 after the completion of the intermediate-pressure refrigerant injection in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Condenser, 3 ... 1st expansion valve (1st decompression device), 4 ... Gas-liquid separator, 5 ... 2nd expansion valve (2nd decompression device), 10 ... Housing, 11 ... Crank Shaft, 12 ... Bearing, 13 ... Crank pin, 14 ... Movable scroll, 14
a ... scroll, 14b ... end plate portion, 15 ... bearing, 16 ...
Fixed scroll, 16a ... Scroll, 17 ... Low pressure port, 18 ... Intermediate pressure suction port, 18a ... Housing port, 18b ... Scroll port, 19 ... Discharge port.

Claims (5)

[Claims] 1. A compressor having a suction port for sucking a low-pressure medium, a compression mechanism for compressing the low-pressure medium sucked from the suction port, and a discharge port for discharging the high-pressure medium compressed by the compression mechanism. The intermediate pressure suction port for injecting an intermediate pressure medium having an intermediate pressure between the low pressure medium and the high pressure medium into a space during a suction stroke of the compression mechanism. . 2. The compressor according to claim 1, wherein when the pressure in the space during the intake stroke in which the intermediate pressure medium is injected becomes equal to the low pressure medium, the low pressure medium is in the intake stroke. A compressor configured to start being sucked into the space. 3. A movable scroll having a spiral scroll and an end plate integrally formed with the scroll, a fixed scroll having the spiral scroll, a suction port for sucking a low-pressure medium, and an orbit of the movable scroll. In a sroll type compressor having a discharge port for discharging a high pressure medium compressed by, a medium pressure medium having a medium pressure between the low pressure medium and the high pressure medium is formed by the movable scroll and the fixed scroll. A sroll type compressor having an intermediate pressure suction port for injection into a space during a suction stroke. 4. The sroll type compressor according to claim 3, wherein the fixed scroll is coupled to the housing to form a closed space, and the scroll is provided at a predetermined portion of a scroll end portion of the movable scroll. A scroll port penetrating the plate portion; and a housing port provided at a predetermined portion of the housing and communicating with the intermediate pressure suction port, wherein the movable scroll is a closed scroll formed by the fixed scroll and the housing. The scroll port and the housing port are configured to overlap each other during the revolution of the orbiting scroll, and when the two ports overlap each other. , So that the inside of the space during the suction stroke communicates with the intermediate pressure suction port. A sroll type compressor characterized by being configured. 5. A compressor according to any one of claims 1 to 4, a condenser that serves as a heat radiating means for the compressed refrigerant discharged from a discharge port of the compressor, and a refrigerant condensed by the condenser. A first decompressor for decompressing, a gas-liquid separator for separating the refrigerant that has passed through the first decompressor into a liquid refrigerant and a gas refrigerant, and a second decompression for decompressing the liquid refrigerant that has passed through the gas-liquid separator A condenser, an evaporator that cools with a low-temperature low-pressure refrigerant decompressed by the second decompressor, a pipe that guides the gas refrigerant separated by the gas-liquid separator to an intermediate pressure suction port of the compressor, A two-stage expansion refrigeration cycle comprising: a pipe that guides a gas refrigerant vaporized by an evaporator to an intake port of the compressor.