JPH08144971A - Scroll type compressor and refrigerating cycle - Google Patents

Abstract

PURPOSE: To provide a highly efficient two-stage compression cycle by using a scroll type compressor. CONSTITUTION: Injection ports 66 and 67 are formed for injecting a gas refrigerant of intermediate pressure separated through a gas-liquid separator 63 into a compression chamber Vc formed between the moving scroll 2 and the fixed scroll 4 of a scroll type compressor 70 via piping 72 and a check valve 72. In this case, the ports 66 and 67 are positioned within the range of ±125 deg. degrees bout a point 180 deg. degrees forward of the rotating position of the scroll 2 where the internal pressure of the chamber Vc is equivalent to the intermediate pressure. As a result, gas is injected stably and highly efficiently via the gradual compression process of the compressor 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type compressor and a refrigerating cycle using the same, and is effectively applied to an air conditioner for automobiles.

[0002]

2. Description of the Related Art In a normal single-stage cycle in which a refrigerant is compressed in only one stage, a scroll type compressor is considered to be a highly efficient compressor, but the compression ratio is the same as when performing heating operation in a heat pump cycle. The large operation causes problems such as a reduction in compressor efficiency and an increase in discharge refrigerant temperature.

In view of this, in Japanese Patent Laid-Open No. 57-28959, a ring type rolling compressor is used, and an injection port for the gas refrigerant and the liquid refrigerant is arranged at a position in the middle of compression of the rolling compressor. It has been proposed to inject the refrigerant into a rolling compressor to improve the efficiency of the compressor.

[0004]

However, in the above publication, the refrigerant is compressed while the ring type rotor of the rolling compressor makes about one rotation (a rotation angle of 360 °). The ratio of the injection port communication time to the entire discharge stroke becomes long, and as a result, the pressure fluctuation due to the rotor compression motion during this injection port communication time becomes large. However, there is a problem in that effective injection cannot be stably performed and it is difficult to improve the efficiency of the compressor.

The present invention has been made in view of the above points,
In the scroll type compressor, attention was paid to the fact that the refrigerant is gently compressed while the orbiting scroll makes multiple revolutions (usually about 3 revolutions), and the optimum opening start timing was set for this scroll type compressor. An object of the present invention is to improve the efficiency of the compressor by making it possible to stably inject the refrigerant into the compressor by combining the injection mechanism.

[0006]

The present invention employs the following technical means in order to achieve the above object. According to the first aspect of the invention, the rotary shaft (1), which rotates by receiving power from the power source and has a crank portion (1a) eccentric from the shaft center by a predetermined amount, and the rotary shaft (1) are rotatable. A supporting housing (5), an orbiting scroll (2) that is rotatably supported by a crank portion (1a) of the rotating shaft (1), and orbits with the rotation of the rotating shaft (1); A fixed scroll (4) that meshes with the orbiting scroll (2) to form two compression chambers (Vc) when it revolves, and a refrigerant sucked from an external two-stage expansion refrigeration cycle. Vc) inlet (6)
8) and a discharge port (69) for discharging the refrigerant compressed in the two compression chambers (Vc) to the external two-stage expansion refrigeration cycle.
And two injection ports (66, 6) for drawing out the refrigerant from the intermediate pressure portion (63) of the external two-stage expansion refrigeration cycle and injecting it into the two compression chambers (Vc).
7) and the two injection ports (6
The opening start timing of (6, 67) is about 180 ° before the rotation angle of the orbiting scroll (2) at which the pressure of the two compression chambers (Vc) becomes the same as the intermediate pressure of the external two-stage expansion refrigeration cycle. The scroll type compressor is characterized in that the opening positions of the injection ports (66, 67) are set so as to be within a predetermined range around the center.

According to a second aspect of the invention, in the scroll compressor according to the first aspect, the opening start timing of the two injection ports (66, 67) is
The orbiting scroll (2) in which the pressure of the two compression chambers (Vc) is the same as the intermediate pressure of the external two-stage expansion refrigeration cycle.
Of the injection port (6
6, 67) are set.

According to a third aspect of the present invention, in the scroll compressor according to the first or second aspect, an external two-stage expansion from the compression chamber (Vc) to the end plate portion (4b) of the fixed scroll (4). A check valve (71) for preventing the reverse flow of the refrigerant to the intermediate pressure portion (63) of the refrigeration cycle is provided. According to the invention of claim 4, claim 1
A scroll type compressor (70) according to any one of 1 to 3; and a condenser (61) into which the gas refrigerant discharged from the discharge port (69) is introduced and which cools and condenses the gas refrigerant. A first pressure reducing means (62) for reducing the pressure of the liquid refrigerant condensed in the condenser (61), and a gas-liquid two-phase refrigerant pressure-reduced in the first pressure reducing means (62) separated into a liquid refrigerant and a gas refrigerant. Gas-liquid separator (63), second decompression means (64) for decompressing the liquid refrigerant separated by the gas-liquid separator (63), and gas-liquid decompressed by the second decompression means (64) An evaporator (65) for evaporating a two-phase refrigerant, an injection passage (72) for introducing the gas refrigerant separated by the gas-liquid separator (63) into the two injection ports (66, 67), The outlet side of the evaporator (65) is connected to the suction port (68) Suction side passage communicating (65a)
It is characterized by a refrigeration cycle equipped with.

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

[0010]

According to the inventions of claims 1 to 4,
The above two injection ports (66, 67)
A predetermined opening start timing is about 180 ° before the rotation angle of the orbiting scroll (2) at which the pressure of the two compression chambers (Vc) becomes the same as the intermediate pressure of the external two-stage expansion refrigeration cycle. By setting the opening position of the injection port (66, 67) so as to be within the range, it is possible to inject the gas refrigerant into the compression chamber so that the pressure condition becomes optimum for the scroll compressor. it can.

Moreover, since the refrigerant can be stably injected into the compressor in combination with the gradual compression action which is a characteristic of the scroll type compressor, the compressor efficiency is improved even under the operating condition of a large compression ratio. In addition to being able to improve the temperature, it is possible to cool the inside of the compression chamber by injecting an intermediate-pressure refrigerant, and suppress an increase in the discharged refrigerant temperature.

In addition to the above-mentioned function and effect, in the third aspect of the invention, the intermediate pressure portion (63) of the external two-stage expansion refrigeration cycle from the compression chamber (Vc) to the end plate portion (4b) of the fixed scroll (4). Since the check valve (71) for preventing the reverse flow of the refrigerant to the compression chamber (Vc) is provided, the check valve (71) is provided.
Can be installed close to the check valve (71) and compression chamber (Vc)
The flow path volume between and can be made small. Since the flow path volume is a dead space that does not contribute to the compression performance for the compression action, the compression performance is hardly adversely affected by reducing the dead space.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) First, a scroll type compressor is used.
A schematic configuration of the stage compression cycle will be described with reference to FIG.
Reference numeral 70 denotes a scroll compressor, which is illustrated in a simplified manner.
Reference numeral 61 denotes a condenser, which is connected to a discharge port 69 provided at the center of the compressor 70 by a pipe and cools and condenses the refrigerant gas discharged from the compressor 70.

Reference numeral 62 is a first throttle valve with a fixed throttle amount, 63 is a gas-liquid separator for separating the gas-liquid two-phase wet refrigerant decompressed by the first throttle valve 62 into liquid and gas, and 64 is a second throttle. With a valve
For example, it comprises a temperature-operated expansion valve that adjusts the refrigerant flow rate so as to maintain the superheat degree of the refrigerant at the outlet of the evaporator 65 at a predetermined value. The evaporator 65 evaporates the refrigerant decompressed by the second throttle valve 64, and the latent heat of evaporation evaporates the external fluid (such as conditioned air).
To cool.

Reference numeral 71 indicates that the refrigerant in the compressor 70 is the gas-liquid separator 6
It is a check valve arranged so as not to flow back to the 3 side. The above-mentioned condenser 61, first throttle valve 62, gas-liquid separator 63, second
The throttle valve 64, the evaporator 65, and the check valve 71 are connected by piping as shown in FIG. Also, the evaporator 65
The pipe 65 a from the outlet is connected to the suction port 68 of the compressor 70. Further, the pipe 72 that guides the gas refrigerant in the gas-liquid separator 63 to the compressor 70 side via the check valve 71 is bifurcated at the outlet of the check valve 71 and is connected to the two injection ports 66 and 67, respectively. It is in communication.

Next, the scroll compressor 70 for two-stage compression, which is a component having the characteristic features of the present invention, will be described. FIG. 2 shows a case where the scroll compressor 70 is applied as a refrigerant compressor in a cooling cycle of an automobile air conditioner. In FIG. 2, the large diameter portion 1b of the crankshaft 1 is rotatably supported by the bearing 30 held by the front housing 5. The crankshaft 1 is connected at its left end side to an electromagnetic clutch or a motor (not shown), and receives the rotational force of an automobile engine, which is a power source, via the electromagnetic clutch.
Alternatively, it receives the rotational force of the motor.

Further, the crankshaft 1 has a crank portion 1a which is eccentric from the center of rotation thereof by a predetermined amount, and a balance weight portion 3 is integrally formed on the crank portion 1a. The crank portion 1 a rotatably supports the orbiting scroll 2 via a bearing 31. Therefore, when the crankshaft 1 is rotated, the orbiting scroll 2 makes an orbital motion according to the eccentric amount of the crank portion 1a.

Here, a driven crank mechanism for increasing the revolution radius of the orbiting scroll 2 and reducing internal leakage of the refrigerant may be used. As is well known, the orbiting scroll 2 includes a scroll-shaped tooth portion 2a and an end plate portion 2b integrally formed with the tooth portion 2a. Reference numeral 4 denotes a fixed scroll composed of a scroll-shaped tooth portion 4a and an end plate portion 4b, which forms several compression chambers Vc by contacting the orbiting scroll 2 in the thrust direction and the radial direction. 1
Reference numerals 1 and 12 denote tip seals attached to the tip end of the tooth portion 2a of the orbiting scroll 2 and the tip end of the tooth portion 4a of the fixed scroller 4, respectively, to seal the leakage in the thrust direction between the compression chambers Vc.

Reference numeral 6 is a rotation preventing mechanism for the orbiting scroll 2.
This is a known mechanism that is composed of a pair of rings fixed to the orbiting scroll 2 and the front housing 5, and a ball sandwiched between them. The end plate portion 4b of the fixed scroll 4
A discharge valve 8 and a valve stopper 9 are fastened to the right end surface of the cylinder by bolts 42, whereby the flow between the discharge chamber Vd and the compression chamber Vc sandwiched between the end plate portion 4b of the fixed scroll 4 and the rear housing 7. Is restricted.

Reference numeral 10 is a shaft sealing device for the crankshaft 1,
This is to prevent the refrigerant gas inside the compressor from leaking to the outside along the protruding end of the crankshaft 1 to the outside. The shaft sealing device 10 is fixed to the front housing 5 with a circlip 43. In the present example, the check valve 71 already described in FIG. 1 is installed on the outer peripheral portion of the end plate portion 4b of the fixed scroll 4, and is configured by the pipe connection portion 71a, the ball-shaped valve 71b, and the spring 71c, This is to prevent the refrigerant in the compression chamber Vc from flowing back to the gas-liquid separator 63 side.

The opening positions of the injection ports 66, 67 arranged on the downstream side of the check valve 71 to the compression chamber Vc are very important for improving the efficiency of the compressor, and the determination method will be described in detail later. . The cooling cycle as the embodiment of the present invention described above belongs to a refrigeration cycle generally called a two-stage compression cycle, and its operation will be described in detail based on the Mollier diagram shown in FIG. Condenser 6
The refrigerant (state i5) that has been liquefied by passing through 1 and being cooled is reduced to an intermediate pressure P1 by the first throttle valve 62 and becomes a vapor-liquid two-phase wet vapor state (mist state).

In this state, the refrigerant introduced into the gas-liquid separator 63 exchanges heat by evaporation and condensation, and becomes a state in which it is separated into a saturated gas and a saturated liquid (state i6, i).
6 '). Then, the liquid refrigerant is sent to the second throttle valve 64, while the gas-liquid refrigerant is sent to the compression chamber Vc from the injection ports 66 and 67 of the compressor 70 through the check valve 71. Here, the weight ratio g of the liquid refrigerant and the gas refrigerant
Since 1 and g2 are due to exchange of heat of evaporation and condensation, they are determined by the following mathematical formulas 1 and 2.

[0023]

## EQU1 ## g1 = (i6'-i5) / ((i6'-i6)

[0024]

## EQU2 ## g2 = 1-g1 The liquid refrigerant g1 is further reduced in pressure P by the second throttle valve 64.
The pressure is reduced to 2, passes through the evaporator 65, and evaporates here to perform cooling. On the other hand, the gas refrigerant g2 guided from the gas-liquid separator 63 to the injection boats 66 and 67 of the compressor 70 via the pipe 72 and the check valve 71 is the refrigerant of g1 pressurized by the compressor 70. Join again.

Here, in order to make a trial calculation of efficiency, the enthalpy at each point is obtained. i1 can be obtained by applying suction pressure and superheat. Since the compression process is regarded as adiabatic change, if the state before compression is determined, the state after compression can be read from the Mollier diagram. That is, if i1 is determined, i2 can be obtained, and i4 can be obtained if i3 is known. i3 is given by Equation 3 below.

[0026]

## EQU3 ## i3 = i6 '+ g1 (i2-i6') If the value of the enthalpy at each point is determined in this way, the calculated coefficient of performance C.I. O. P (that is, cooling capacity / power consumption)
Is given by the following Equation 4.

[0027]

## EQU00004 ## C.I. O. P = g1 (i1-i6) / {g1 (i2-i1) + (i4-i3)} In order to compare the efficiency of the normal refrigeration cycle and the two-stage compression cycle, the C.I. O. An example of calculating P is shown in FIGS. 4 (a) and 4 (b). Depending on the pressure conditions, a two-stage compression cycle can be expected to improve efficiency by several tens of percent. This improvement in efficiency means that even if the cooling capacity decreases due to the decrease in the flow rate of the refrigerant passing through the evaporator 65,
This can be realized by obtaining a compressor power saving effect that exceeds the reduction.

Next, the operation of the scroll compressor 70 used as a refrigerant compressor for the two-stage compression cycle in the above embodiment will be described. FIG. 5 shows, in the order of (a), (b), (c) and (d), a state in which the revolution angle of the orbiting scroll 2 is approximately 90 ° from the state (a) where the suction of the compressor 70 is completed. At this time, as can be seen in FIG. 5, the scroll compressor has two compression chambers (working chambers) Vc having the same pressure at the same time. Refrigerant was simultaneously drawn in in (a) 2
Next, the two compression chambers Vc-1 have 90 ° swivel scrolls 2.
In the turned state (b), it is moving to the position of Vc-2. In this way, the compression chamber is Vc-1 → Vc-2 → Vc
-3 → Vc-4, the position is sequentially moved and the volume thereof is reduced, and finally, when the refrigerant pressure of the condenser pressure of the external refrigeration cycle is reached, the discharge valve 8 is pushed open to open the central portion. The compressed refrigerant gas is discharged from the discharge port 69 into the discharge chamber Vd.

Therefore, the sucked refrigerant is compressed by the revolution of the crankshaft 1 and the orbiting scroll 2 revolving. If injection ports 66 and 67 are opened in the middle of the series of compression strokes and the gas refrigerant separated by the gas-liquid separator 63 is injected into the compression chamber Vc from the injection ports 66 and 67, Stage compression is performed.

However, this injection port 6
6 and 67, as shown in FIG. 6, from the closed state as shown in (a) to the opened state as shown in (b), (c), and (d), the rotation angle of the orbiting scroll 2 (revolution movement). When the rotation angle) reaches 360 °, the closed state of FIG. During this time, the compression chamber Vc is performing a compression motion, and the pressure at the positions of the injection ports 66 and 67 is fluctuating. Therefore, in order to ensure the effect of the two-stage compression, this injection port 66, 6
It is necessary to optimally select the position of 7, that is, the injection start time.

Therefore, the injection ports 66, 6
How to determine the position of 7 will be described below. Here, it is assumed that the scroll compressor 70 used in this two-stage compression cycle compresses the refrigerant with the pressure characteristic shown by the curve in FIG. The horizontal axis in FIG. 7 is the rotation angle of the orbiting scroll 2, and the vertical axis is the refrigerant pressure in the compression chamber Vc. At this time, the intermediate pressure and the coefficient of performance C.I. O. The relationship of P is shown in FIG. In the refrigeration cycle, there are pressure conditions such as suction pressure Ps and discharge pressure Pd that are often used for performance studies.
8A is Pd / Ps = 10/2, and B is Pd / Ps =
At 15/2, C has Pd / Ps = 20/2 (Unit is kgf / cm
It is the pressure condition of ² ). Under each of these three pressure conditions, the pressure of the gas refrigerant separated by the gas-liquid separator 63,
That is, the intermediate pressure is 6 kgf / cm ² , 7.8 kgf / cm ² , 9.
C. at the point of 5 kgf / cm ² . O. P is the highest.

Therefore, the above-mentioned C. O. The target intermediate pressure is about 7.7 (kgf / cm ² ) which is the center value of the shaded area A indicating the intermediate pressure range where P is the highest. On the other hand, the compression chamber Vc of the compressor 70 becomes 7.7 (kgf / cm ² ).
FIG. 9 shows the state when the orbiting scroll 2 orbits the orbiting scroll 2 by about 435 ° with the suction completion position of the orbiting scroll 2 set to 0 ° (see FIG. 7).

FIG. 10 shows the experimental results under the pressure condition of Pd / Ps = 15/2. As shown in FIG.
The positions of the injection ports 66 and 67 (injection start angle) are C.I. when the injection is started when the orbiting scroll 2 orbits the orbiting scroll 2 about 255 ° with the suction completion position of the orbiting scroll 2 being 0 °. O. It has been confirmed that P becomes maximum.

Here, the C. O. If the target is to improve P, the range of the B zone in FIG. 10, that is, the injection start may be set between about 130 ° and 380 °. This has been found to be the same under other pressure conditions. Therefore, first, the intermediate pressure for injection is determined, and about 180 ° before the compression chamber Vc reaches the intermediate pressure (435 ° -255 ° = 180 ° described above).
If the injection ports 66 and 67 are provided at positions where injection is started within a range of ± 125 ° with respect to the center, the two-stage compression C.I. O.
P can be improved by at least about 10%, and at the same time, the discharge temperature can be reduced.

Next, the effect of the cooling cycle of the illustrated embodiment will be described. If, in a normal cycle (see Fig. 4 (a)), when the heat pump is operated under a pressure condition where the compression ratio is large, the internal leakage of the compressor becomes large and the efficiency is lowered, and further the discharge temperature rises. Invite. In order to prevent this decrease in efficiency, measures such as reducing the clearances in the compression chamber Vc can be considered, but it is difficult to realize from the viewpoints of workability and durability.

However, if the two-stage compression cycle (see FIG. 4 (b)) can be applied, the refrigerant cooled and liquefied in the condenser 61 is passed through the first throttle valve 62 to reduce the pressure to a predetermined intermediate pressure, and the gas-liquid two The phase-phase refrigerant is separated into gas and liquid by the gas-liquid separator 63, and only the gas refrigerant is compressed in the compression chamber V of the compressor 70.
By returning to c, the refrigerant in the compression chamber Vc is cooled and, at the same time, compressed at the highest pressure for compression. Therefore, the efficiency of the compressor is significantly improved, and as a result, the efficiency of the cooling cycle is also improved. Therefore, even if the clearance of the compression chamber Vc is not forcibly reduced, the injection ports 66 and 67 are simply processed at the intended positions to achieve high efficiency and lower the discharge temperature even under an operating condition with a large compression ratio. You can

(Second Embodiment) In the first embodiment, the check valve 7
1 is installed integrally with the end plate portion 4b of the fixed scroll 4, but as shown in FIG. 11, an injection joint 5 having injection ports 66 and 67 formed at the tips thereof.
The check valve 71 may be externally attached to the outside of the compressor 70 by fixing 0 and 50 to the rear housing 7 via the copper washers 51 and 51.

With this, the same operation and effect as those of the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is a cycle diagram schematically illustrating a cooling cycle of two-stage compression using a scroll type compressor of the present invention.

FIG. 2 is a vertical cross-sectional view showing a first embodiment of the scroll compressor of the present invention.

FIG. 3 is a Mollier diagram for explaining the operation of the cooling cycle of the embodiment.

FIG. 4 is a pair of Mollier diagrams for comparing the effect of the cooling cycle of the embodiment with the conventional example, (a) shows the conventional cooling cycle, and (b) is the two-stage compression cycle according to the present invention. Indicates.

5 (a) to 5 (d) are cross-sectional views of essential parts showing the operating state of the scroll compressor of the embodiment of the present invention every 90 ° rotation of the crankshaft.

6 (a) to 6 (d) are cross-sectional views of essential parts showing the state of the injection port in the scroll compressor of the embodiment of the present invention every 90 ° rotation of the crankshaft.

FIG. 7 is a graph showing boosting characteristics of the scroll compressor according to the embodiment of the present invention.

FIG. 8 shows the intermediate pressure and C.I. O. It is a graph which shows the relationship of P.

FIG. 9 shows a scroll compressor of an embodiment of the present invention at 435 °.
It is a principal part sectional view which shows the compression chamber at the time of turning.

10 is a diagram showing an injection start position and C.I. O. It is a graph which shows the relationship of P.

FIG. 11 is a longitudinal sectional view showing a second embodiment of the scroll compressor of the present invention.

[Explanation of symbols]

1 ... Crank shaft, 1a ... Crank part, 2 ...
Orbiting scroll 2a ... Tooth portion, 2b ... End plate portion, 4 ...
... Fixed scroll, 4a ... Tooth part, 4b ... End plate part, 5
...... Front housing, 6 ... Rotation prevention mechanism, 7 ...
Rear housing, 8 ... Discharge valve, 61 ... Condenser, 62
...... First throttle valve, 63 …… Gas-liquid separator, 64 …… Second throttle valve, 65 …… Evaporator, 66,67 …… Injection port, 68 …… Suction port, 69 …… Discharge port, 70 ......
Scroll type compressor, 71 ... Check valve, 72 ... Injection piping, Vc ... Compression chamber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Inagaki 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute, Inc. (72) Inventor Yuji Wakayama 1-1, Showa-cho, Kariya, Aichi Japan Denso Co., Ltd.

Claims (4)

[Claims] 1. A rotary shaft having a crank portion which is rotated by receiving power from a power source and is eccentric from a shaft center by a predetermined amount, a housing for rotatably supporting the rotary shaft, and a crank portion of the rotary shaft. An orbiting scroll that is rotatably supported and that makes an orbital motion with the rotation of the rotating shaft, a fixed scroll that meshes with the orbiting scroll when the orbiting scroll makes an orbital motion, and two external stages. An inlet for introducing the refrigerant sucked from the expansion refrigeration cycle into the two compression chambers, an outlet for discharging the refrigerant compressed in the two compression chambers to the external two-stage expansion refrigeration cycle, and an external two-stage expansion refrigeration cycle And two injection ports for injecting the refrigerant into the two compression chambers from the intermediate pressure region of the two injection ports, and opening the two injection ports. The start timing is set within a predetermined range centered about 180 ° before the rotation angle of the orbiting scroll where the pressures of the two compression chambers are the same as the intermediate pressure of the external two-stage expansion refrigeration cycle. A scroll type compressor characterized in that the opening position of the injection port is set. 2. The opening start timing of the two injection ports is about 180 ° before the rotation angle of the orbiting scroll at which the pressure of the two compression chambers becomes the same as the intermediate pressure of the external two-stage expansion refrigeration cycle. ± about 1 at the center
The scroll compressor according to claim 1, wherein the opening position of the injection port is set so as to be within a range of 25 °. 3. A check valve for preventing backflow of a refrigerant from the compression chamber to an intermediate pressure portion of an external two-stage expansion refrigeration cycle is provided in an end plate portion of the fixed scroll. Item 3. The scroll compressor according to Item 1 or 2. 4. The scroll compressor according to claim 1, a condenser that introduces a gas refrigerant discharged from the discharge port, cools the gas refrigerant, and condenses the gas refrigerant. A first pressure reducing means for reducing the pressure of the liquid refrigerant condensed by the condenser; a gas-liquid separator for separating the gas-liquid two-phase refrigerant pressure-reduced by the first pressure reducing means into a liquid refrigerant and a gas refrigerant; The second decompression means for decompressing the liquid refrigerant separated by the separator, the evaporator for evaporating the gas-liquid two-phase refrigerant decompressed by the second pressure reduction means, and the gas refrigerant separated by the gas-liquid separator. A refrigeration cycle comprising: an injection passage introduced into the two injection ports; and a suction-side passage that communicates the outlet side of the evaporator with the suction port.