JP2004232996A - Refrigeration cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigeration cycle device with a compact accumulator tank. <P>SOLUTION: This refrigeration cycle device separates gas-liquid of outlet side refrigerant of an evaporator 4 inside the accumulator tank 7, takes out gas refrigerant inside the accumulator tank 7 and liquid refrigerant rest in the lower part in the accumulator tank 7 and returns both the refrigerant to the suction side of a compressor 1. The device communicates the outlet side of the evaporator 4 with the suction side of the compressor via a main passage 5, branches part of the outlet side refrigerant of the evaporator 4 with a branch passage 6 from the main passage 5 for introduction into the accumulator tank 7, takes out the gas refrigerant inside the accumulator tank 7 and the liquid refrigerant rest in the lower part in the accumulator tank 7 into a refrigerant return passage 8, and joins the outlet side of the refrigerant return passage 8 to a downstream side portion of the main passage 5 than a restriction portion 11. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigeration cycle apparatus having an accumulator tank for separating gas-liquid of an evaporator outlet side refrigerant.
[0002]
[Prior art]
Conventionally, various types of refrigeration cycle devices having an accumulator tank for separating the vapor-liquid of the evaporator outlet-side refrigerant have been proposed (for example, see Patent Document 1).
[0003]
4 and 5 show a conventional refrigeration cycle apparatus and an accumulator tank, in which the entire amount of the refrigerant on the outlet side of the evaporator 4 is introduced into the accumulator tank 7, and the gas-liquid of the introduced refrigerant is stored in the accumulator tank 7. And the liquid refrigerant is stored in the lower part of the tank 7.
[0004]
Then, a U-shaped refrigerant return pipe 73 is arranged in the tank 7, and the gas refrigerant in the upper part of the tank 7 is sucked into the refrigerant return pipe 73 from the gas suction port 73 a at the upper part of the refrigerant return pipe 73, and the refrigerant is returned. The liquid refrigerant and the oil dissolved in the liquid refrigerant are sucked into the refrigerant return pipe 73 from an oil return hole 73b opened at the bottom of the pipe 73. The liquid refrigerant and the oil are mixed with the gas refrigerant in the refrigerant return pipe 73, and the mixed refrigerant is sucked into the compressor 1.
[0005]
[Patent Document 1]
JP-A-48-99940 [0006]
[Problems to be solved by the invention]
By the way, in the above-described conventional technology, the entire amount of the evaporator outlet-side refrigerant is introduced into the accumulator tank 7 to perform gas-liquid separation. Increase. In the case of a vehicle, since the accumulator tank 7 is mounted in an engine room where space restrictions are strong, there is a serious problem in mounting the accumulator tank 7 on the vehicle.
[0007]
The present invention has been made in view of the above circumstances, and has as its object to reduce the size of an accumulator tank.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the invention, the gas-liquid of the refrigerant on the outlet side of the evaporator (4) is separated in the accumulator tank (7), and the gas refrigerant in the accumulator tank (7); In a refrigeration cycle device, a liquid refrigerant collected in a lower portion of an accumulator tank (7) and oil dissolved in the liquid refrigerant are taken out and returned to a suction side of the compressor (1).
A main passage (5) for connecting the outlet side of the evaporator (4) to the suction side of the compressor (1), and a part of the evaporator (4) outlet side refrigerant branched from the main passage (5) to accumulator tank ( A branch passage (6) introduced into the accumulator tank (7), a gas refrigerant in the accumulator tank (7), and a refrigerant return passage (8) for removing liquid refrigerant accumulated in the lower portion of the accumulator tank (7) and oil dissolved in the liquid refrigerant. And the outlet of the refrigerant return passage (8) is joined to the main passage (5) downstream of the branch position of the branch passage (6).
[0009]
According to this, a part of the refrigerant on the outlet side of the evaporator (4) is branched from the main passage (5) to the branch passage (6), and the branched refrigerant is introduced into the accumulator tank (7) to remove gas-liquid of the refrigerant. Since the separation is performed, the space volume for refrigerant gas-liquid separation in the accumulator tank (7) can be significantly reduced as compared with the related art, and the accumulator tank (7) can be downsized.
[0010]
Further, the gas refrigerant in the accumulator tank (7), the liquid refrigerant in the lower part of the accumulator tank (7), and the oil dissolved in the liquid refrigerant can be returned to the suction side of the compressor (1) through the refrigerant return passage (8). Therefore, the function of adjusting the flow rate of the circulating refrigerant in the cycle and the function of returning the oil by adjusting the amount of the liquid refrigerant accumulated in the accumulator tank (7) can be exerted in the same manner as the normal one.
[0011]
According to a second aspect of the present invention, in the first aspect, the main passage (5), the branch passage (6), and the refrigerant return passage (8) are provided in the accumulator tank (7).
[0012]
According to this, it is only necessary to connect the inlet of the main passage (5) to the outlet of the evaporator (4) and to connect the outlet of the main passage (5) to the suction of the compressor (1). (6) It is not necessary to newly add a refrigerant passage connecting portion for the refrigerant return passage (8). Therefore, even if the branch passage (6) is added, the work of connecting the accumulator tank (7) can be easily performed by the same work as the conventional one.
[0013]
According to a third aspect of the present invention, in the first or second aspect, the throttle portion (11) is provided between the branch position of the branch passage (6) and the merging position of the refrigerant return passage (8) in the main passage (5). ) Is arranged.
[0014]
Due to this, the amount of gas refrigerant flowing out from the refrigerant return passage (8) to the junction of the main passage (5) is ensured even when the cycle circulation refrigerant flow rate is small, due to the differential pressure generated before and after the throttle portion (11). Accordingly, the amount of the liquid refrigerant sucked into the refrigerant return passage (8) can be secured. Therefore, the oil return amount can be ensured even at a small flow rate.
[0015]
According to the fourth aspect of the present invention, in the first or second aspect, the guide member (12) that takes in the liquid refrigerant in the refrigerant flowing in the main passage (5) and guides the refrigerant to the branch passage (6) is provided. ).
[0016]
Thus, the liquid refrigerant in the main passage (5) can be reliably introduced from the branch passage (6) into the accumulator tank (7) by the guide member (12). Therefore, even when the suction pressure of the compressor (1) suddenly drops and liquid returns to the compressor (1) is likely to occur, such as when the compressor (1) is started (transient), The occurrence of liquid return to (1) can be suppressed.
[0017]
In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means described in embodiment mentioned later.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
FIG. 1 is a basic configuration diagram of a refrigeration cycle device according to a first embodiment, and shows a case where the present invention is applied to a refrigeration cycle device for vehicle air conditioning. FIG. 2 is a cross-sectional view of the accumulator tank shown in FIG.
[0019]
The compressor 1 of the refrigeration cycle apparatus is belt-driven by a vehicle engine (not shown) via an electromagnetic clutch or the like (not shown). The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the condenser 2. The condenser 2 is a radiator of the refrigerant, and the outside air is blown by an electric cooling fan (not shown). Therefore, the discharged gas refrigerant radiates heat to the outside air and condenses.
[0020]
The liquid refrigerant condensed in the condenser 2 is decompressed by the decompression device 3 to be in a low-pressure gas-liquid two-phase state. The pressure reducing device 3 is configured by a fixed restrictor such as an orifice, a nozzle, a capillary tube, and the like. Note that the pressure reducing device 3 may be configured by a variable throttle whose opening is adjusted according to the state (pressure and temperature) of the high-pressure refrigerant, or a combination of a fixed throttle and a variable throttle.
[0021]
The evaporator 4 is for evaporating the low-pressure refrigerant that has passed through the pressure reducing device 3 by absorbing heat from the air blown by an air-conditioning blower (not shown). The evaporator 4 is arranged in a case of an air-conditioning indoor unit (not shown), and the cool air cooled by the evaporator 4 is blown into the vehicle interior after its temperature is adjusted by a heater core (not shown) as is well known.
[0022]
The outlet side of the evaporator 4 is provided with a main passage 5 through which a main flow of the outlet refrigerant of the evaporator 4 (saturated gas containing the gas refrigerant evaporated by the evaporator 4) flows. A branch passage 6 for branching the section is provided, the branch refrigerant from the branch passage 6 is introduced into the accumulator tank 7, and gas and liquid of the introduced refrigerant are separated in the accumulator tank 7.
[0023]
Then, the gas refrigerant and the liquid refrigerant in the accumulator tank 7 and the oil dissolved in the liquid refrigerant are joined from the return passage 8 to the main passage 5, and the main flow of the evaporator outlet refrigerant passing through the main passage 5 and the inside of the accumulator tank 7 Is returned to the compressor 1. .
[0024]
As shown in FIG. 2, the accumulator tank 7 has a vertically long, substantially cylindrical tank body 70. The tank body 70 is made of a metal such as aluminum, and forms a space 71 for gas-liquid mixing therein. The upper wall 72 of the tank body 70 defines the upper part of the space 71, and a circular through hole is formed so as to penetrate the upper wall 72 in the horizontal direction to form the main passage 5.
[0025]
One end (upstream end) of the main passage 5 communicates with the outlet of the evaporator 4 via the inlet connection passage 9. The other end (downstream end) of the main passage 5 communicates with the suction side of the compressor 1 via the outlet connection passage 10. A throttle 11 is provided at an intermediate portion of the main passage 5. A branch hole 6 is formed in the upper surface wall 72 of the tank body 70 at a position upstream of the throttle 11 by opening a communication hole that vertically communicates the main passage 5 with the inside of the space 71.
[0026]
On the other hand, a U-shaped refrigerant return pipe 73 is disposed in the space 71 of the tank body 70, and one end of the U-shaped refrigerant return pipe 73 is opened to a gas refrigerant area in the upper part of the space 71 to perform gas suction. The mouth 73a is formed. In addition, the U-shaped bottom of the refrigerant return pipe 73 is arranged in the liquid refrigerant area in the lower part of the space 71, and an oil return hole 73b composed of a small diameter circular hole is opened in the U-shaped bottom. The liquid refrigerant and oil dissolved in the liquid refrigerant are sucked into the refrigerant return pipe 73 from the oil return hole 73b.
[0027]
The other end of the U-shaped refrigerant return pipe 73 is fitted and fixed in the hole 72 a of the upper wall 72 of the tank body 70, and the other end of the refrigerant return pipe 73 is located downstream of the throttle 11 in the main passage 5. It merges into the side part. Accordingly, in the tank configuration of FIG. 2, the refrigerant return passage 8 of FIG. 1 is formed by the passage inside the refrigerant return pipe 73.
[0028]
In the space 71 of the tank body 70, a baffle plate 74 is disposed at an intermediate portion between the lower (outlet) opening end of the branch passage 6 and the gas suction port 73a of the refrigerant return pipe 73. The baffle plate 74 has a disk-like plate shape and has a mounting hole 74a. The baffle plate 74 is fitted and fixed to the refrigerant return pipe 73 at the portion of the mounting hole 74a.
[0029]
The baffle plate 74 collides the inlet refrigerant flowing into the space 71 from the branch passage 6 to prevent the inlet refrigerant from directly flowing into the gas suction port 73a. Also, a predetermined gap 75 is formed between the outer peripheral portion of the disk of the baffle plate 74 and the inner peripheral surface of the tank body 70, and the refrigerant that has collided with the baffle plate 74 passes through the gap portion 75 and goes down. To move to.
[0030]
Next, the operation of the above configuration will be described. When the compressor 1 is operated, the discharge gas of the compressor 1 radiates heat in the condenser 2 and condenses, and the condensed liquid refrigerant is decompressed by the decompression device 3 to be in a low-temperature low-pressure gas-liquid two-phase state. . The low-pressure refrigerant flows into the evaporator 4 and absorbs heat from the conditioned air to evaporate. At the outlet of the evaporator 4, under normal cooling heat load conditions, the gas refrigerant and the liquid refrigerant coexist in a saturated state, and the main flow of the saturated refrigerant at the evaporator outlet passes through the main passage 5 to the suction side of the compressor 1. Heading.
[0031]
A throttle 11 is arranged in the middle of the main passage 5, and a predetermined differential pressure is generated between before and after the throttle 11. Therefore, a part of the saturated refrigerant at the outlet of the evaporator is branched from the upstream portion of the throttle 11 to the branch passage 6, passes through the branch passage 6, and is introduced into the tank body 70 of the accumulator tank 7.
[0032]
The refrigerant introduced from the branch passage 6 collides with the upper surface of the baffle plate 74, and then moves downward in the space 71 of the tank main body 70 through the gap 75 at the outer periphery of the baffle plate 74. Here, the baffle plate 74 prevents the introduced refrigerant from flowing directly into the gas suction port 73a, and also prevents the introduced refrigerant from colliding with the liquid level A of the liquid refrigerant in the tank body 70 and disturbing the liquid level A. By doing so, the gas-liquid separation action inside the space 71 of the tank body 70 is improved.
[0033]
The liquid refrigerant accumulates below in the space 71 of the tank body 70 due to the density difference between the gas refrigerant and the liquid refrigerant, and the gas refrigerant is separated above the liquid surface A of the liquid refrigerant. Then, the gas refrigerant is sucked into the refrigerant return pipe 73 from the gas suction port 73 a opened at the upper part in the space 71. The liquid refrigerant and oil dissolved in the liquid refrigerant are sucked into the refrigerant return pipe 73 from the oil return hole 73b opened in the liquid refrigerant.
[0034]
Therefore, the liquid refrigerant and the oil are mixed with the gas refrigerant from the gas suction port 73 a in the refrigerant return pipe 73 and join the downstream side of the throttle 11 of the main passage 5. Therefore, the refrigerant is sucked into the compressor 1 in a state where the return refrigerant from the refrigerant return pipe 73 joins the main flow of the evaporator outlet refrigerant passing through the main passage 5.
[0035]
When the cooling heat load of the evaporator 4 increases and the outlet refrigerant of the evaporator 4 enters a superheated gas state having a degree of superheat, the superheated gas refrigerant is introduced from the branch passage 6 into the tank body 70 of the accumulator tank 7. Then, the stored liquid refrigerant in the tank body 70 is evaporated. Thereby, the liquid refrigerant stored in the tank body 70 can be supplied to the suction side of the compressor 1 as a gas refrigerant, and the flow rate of the circulating refrigerant in the cycle can be increased. Thereby, the outlet refrigerant of the evaporator 4 returns to the saturated state.
[0036]
Conversely, when the cooling heat load of the evaporator 4 decreases, the dryness of the saturated refrigerant at the outlet of the evaporator 4 decreases, so that the amount of liquid refrigerant accumulated in the tank body 70 increases and the circulating refrigerant flow rate in the cycle decreases. it can. As a result, the dryness of the refrigerant at the outlet of the evaporator 4 is excessively reduced, and the refrigerant is prevented from being sucked into the compressor 1 (liquid back).
[0037]
By the way, according to the present embodiment, the main flow of the outlet refrigerant of the evaporator 4 passes through the main passage 5 and is directly sucked into the compressor 1, and only a part of the outlet refrigerant of the evaporator 4 branches to the branch passage 6. Since it is designed to be introduced into the tank body 70 of the accumulator tank 7, the entire amount of the outlet refrigerant of the evaporator 4 is introduced into the tank body 70 of the accumulator tank 7 as in the prior art shown in FIGS. In comparison, the space for gas-liquid separation of the tank body 70 can be reduced, and the accumulator tank 7 can be downsized.
[0038]
In order to effectively reduce the size of the accumulator tank 7, it is preferable that the ratio of the branch refrigerant to the branch passage 6 be smaller than the ratio of the mainstream refrigerant passing through the main passage 5.
[0039]
Further, the main passage 5 and the branch passage 6 are formed in the tank main body 70 of the accumulator tank 7 itself, and the outlet of the refrigerant return pipe 73 (refrigerant return passage 8) is joined to the main passage 5 downstream of the throttle portion 11. Therefore, the connection points of the accumulator tank 7 with the external refrigerant passages 9 and 10 can be limited to only two positions, the upstream end and the downstream end of the main passage 5. Therefore, even if the branch passage 6 is formed, the number of connection points does not increase with respect to the general accumulator tank 7 in FIG. 5, and the refrigerant passage connection operation can be easily performed.
[0040]
In the prior art, a pressure equalizing hole 73c for preventing liquid refrigerant return when the compressor 1 is stopped is provided in the refrigerant return pipe 73 on the downstream side of the oil return hole 73b and above the liquid level A. Must be opened. That is, when the temperature of the accumulator tank 7 becomes higher than the suction side of the compressor 1 when the compressor 1 is stopped, and the refrigerant pressure in the accumulator tank 7 becomes higher than the refrigerant pressure on the compressor 1 suction side, the liquid refrigerant in the accumulator tank 7 Is pushed out from the oil return hole 73b toward the compressor 1 suction side. However, when the equalizing hole 73c is formed, the downstream pressure of the oil return hole 73b in the refrigerant return pipe 73 becomes equal to the refrigerant pressure in the accumulator tank 7, so that the liquid refrigerant draws the compressor 1 from the oil return hole 73b. It can be prevented from being pushed out to the side.
[0041]
On the other hand, according to the present embodiment, since the outlet of the refrigerant return pipe 73 joins the downstream of the throttle 11 of the main passage 5, the outlet of the refrigerant return pipe 73 is connected to the main passage when the compressor 1 is stopped. 5 and the branch passage 6 are maintained at the same state (equalized state) as the refrigerant pressure in the accumulator tank 7. Therefore, it is possible to prevent the liquid refrigerant in the accumulator tank 7 from being pushed out from the oil return hole 73b to the compressor 1 suction side without forming the pressure equalizing hole 73c in the refrigerant return pipe 73.
[0042]
Further, according to the prior art, since the entire amount of the refrigerant at the outlet of the evaporator 4 is introduced into the tank body 70 of the accumulator tank 7, the refrigerant introduced into the tank body 70 collides with the baffle plate 74 and scatters widely. Thus, the required area of the baffle plate 74 increases. Moreover, it is necessary to form the baffle plate 74 in an umbrella shape so as to cover both the gas suction port 73a and the equalizing hole 73c. For these reasons, the manufacturing cost of the baffle plate 74 increases.
[0043]
On the other hand, according to the present embodiment, only a part of the outlet refrigerant of the evaporator 4 branches into the branch passage 6 and is introduced into the tank main body 70 of the accumulator tank 7, so that the refrigerant after the collision with the baffle plate 74 The scattering range is reduced, and the required area of the baffle plate 74 can be made smaller than that of the conventional baffle plate 74. In addition, since the pressure equalizing hole 73c can be eliminated, the shape of the baffle plate 74 can be made a simple disk shape. Therefore, the manufacturing cost of the baffle plate 74 can be reduced as compared with the related art.
[0044]
(2nd Embodiment)
FIG. 3 shows a second embodiment, in which a liquid refrigerant in the main passage 5 is selectively (preferentially) guided toward the branch passage 6 at a branch portion of the main passage 5 from the branch passage 6. The member 12 is arranged.
[0045]
By the way, in the inlet-side connection passage 9 (outlet-side passage of the evaporator 4) and the main passage 5 of the accumulator tank 7, the saturated refrigerant liquid refrigerant and the gas refrigerant flow in an annular flow. That is, since the liquid refrigerant has a higher viscosity than the gas refrigerant, the liquid refrigerant flows annularly along the inner wall surfaces of the passages 9 and 5, and the gas refrigerant flows through the center of the annular liquid refrigerant flow.
[0046]
Therefore, in the second embodiment, the guide member 12 provided at a branch portion of the main passage 5 with the branch passage 6 is formed in an L-shaped cross section having first and second guide surfaces 12a and 12b. The first guide surface 12a is formed in an arc shape along the lower inner wall surface of the main passage 5, and the second guide surface 12b is vertically connected to the downstream end of the first guide surface 12a. The distal end (lower end) of the second guide surface 12b is fixed at a position downstream of the upper (inlet) open end of the branch passage 6 on the lower inner wall surface of the main passage 5.
[0047]
Thus, the liquid refrigerant flowing between the lower inner wall surface of the main passage 5 and the first guide surface 12a can be reliably flown into the upper open end of the branch passage 6 by the second guide surface 12b.
[0048]
In a refrigeration cycle device for vehicle air conditioning, the operation of the compressor 1 is interrupted by an electromagnetic clutch to control the temperature of the air blown out of the evaporator 4. Therefore, the compressor 1 repeatedly operates and stops frequently. Immediately after the compressor 1 is stopped and restarted, the suction pressure of the compressor 1 rapidly drops and liquid refrigerant returns to the compressor 1 easily. However, according to the second embodiment, the main passage 5 The liquid refrigerant B flowing along the inner wall surface of the tank can be selectively introduced into the tank main body 70 from the branch passage 6 by the guide member 12. Thereby, the occurrence of the return of the liquid refrigerant immediately after the restart of the compressor 1 can be suppressed.
[0049]
When the dryness of the outlet refrigerant of the evaporator 4 decreases and the ratio of the liquid refrigerant increases, the liquid refrigerant B moves to the lower part in the circumferential direction of the inner wall surface of the main passage 5 under the influence of gravity. Come. Therefore, the liquid refrigerant B transferred to the lower inner wall surface of the main passage 5 can be effectively introduced into the tank main body 70 by the guide member 12.
[0050]
In the second embodiment, since a part of the refrigerant passing through the main passage 5 can be surely introduced into the tank main body 70 by the guide member 12, the throttle portion 11 of the first embodiment is not provided.
[0051]
Further, in the second embodiment, the guide member 12 is formed in an arc shape only on a lower portion in the circumferential direction of the inner wall surface of the main passage 5, but the guide member 12 is formed in a circular shape on the inner wall surface of the main passage 5. It may be formed in an annular shape extending all around in the direction.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a refrigeration cycle showing a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the accumulator tank according to the first embodiment.
FIG. 3 is a sectional view of an accumulator tank according to a second embodiment.
FIG. 4 is a circuit diagram of a conventional refrigeration cycle.
FIG. 5 is a sectional view of a conventional accumulator tank.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Condenser (radiator), 3 ... Decompression device, 4 ... Evaporator,
5 main passage, 6 branch passage, 7 accumulator tank,
8 ... Coolant return passage.

Claims (4)

A compressor (1), a radiator (2) for radiating the refrigerant discharged from the compressor (1), and a decompression device (3) for decompressing the high-pressure refrigerant passing through the radiator (2). An evaporator (4) for evaporating the low-pressure refrigerant that has passed through the decompression device (3); a refrigerant at an outlet side of the evaporator (4) flows into the evaporator (4); An accumulator tank (7),
In a refrigeration cycle apparatus, a gas refrigerant in the accumulator tank (7), a liquid refrigerant accumulated in a lower portion of the accumulator tank (7), and oil dissolved in the liquid refrigerant are taken out and returned to a suction side of the compressor (1).
A main passage (5) for communicating an outlet side of the evaporator (4) with a suction side of the compressor (1);
A branch passage (6) for branching a part of the refrigerant on the outlet side of the evaporator (4) from the main passage (5) and introducing the branched refrigerant into the accumulator tank (7);
A gas refrigerant in the accumulator tank (7), a liquid refrigerant collected in a lower portion of the accumulator tank (7), and a refrigerant return passage (8) for extracting oil dissolved in the liquid refrigerant;
A refrigeration cycle apparatus wherein the outlet of the refrigerant return passage (8) is joined to the main passage (5) downstream of a branch position of the branch passage (6). The refrigeration cycle apparatus according to claim 1, wherein the main passage (5), the branch passage (6), and the refrigerant return passage (8) are provided in the accumulator tank (7). The throttle (11) is arranged between the branch position of the branch passage (6) and the merging position of the refrigerant return passage (8) in the main passage (5). 3. The refrigeration cycle apparatus according to 2. The guide member (12) for taking in a liquid refrigerant in the refrigerant flowing in the main passage (5) and guiding the refrigerant to the branch passage (6) is arranged in the main passage (5). 3. The refrigeration cycle apparatus according to 2.

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