JP2008057810A - Refrigerating cycle apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle apparatus, surely returning staying lubricating oil to a compressor even during the stop of a refrigerant flow. <P>SOLUTION: This refrigerating cycle apparatus includes: a compressor 16; a condenser 17; two evaporators 15, 33 disposed in parallel between the condenser 17 and the compressor 16; a first low pressure side refrigerant pipeline 26 connected from one front seat side evaporator 15 to a suction part 16b of the compressor 16; and an underfloor low pressure pipeline 39 disposed in a position lower than the suction part 16b of the compressor 16 and an outlet part 33a of the other rear seat evaporator 33 to join a first low pressure side refrigerant pipeline 26 from the rear seat side evaporator 33, and connected to the suction part 16b of the compressor 16. The underfloor low pressure pipeline 39 is provided with a trap part 30b for temporarily retaining lubricating oil in the refrigerant circulated through the first low pressure side refrigerant pipeline 26. Thus, even during the stop of refrigerant flow, the retaining lubricating oil can be surely returned to the compressor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus having a plurality of evaporators provided in parallel, and in particular, a front seat side air conditioning unit that air-conditions a region on the front seat side of a vehicle interior and a region on the rear seat side of the vehicle interior. It is suitable for application to a vehicle air conditioner including a rear seat air conditioning unit.

  This type of refrigeration cycle apparatus includes, for example, a refrigeration cycle apparatus including a compressor, a condenser, and two evaporators arranged in parallel between the condenser and the compressor, as shown in Patent Document 1. Are known.

  In this refrigeration cycle apparatus, a first low pressure side refrigerant pipe connected from one evaporator to the compressor and a second low pressure connected to the compressor by joining from the other evaporator to the first low pressure side refrigerant pipe. Side refrigerant piping is provided. The lowermost part of the second low-pressure side refrigerant pipe is arranged at a position lower than the suction part of the compressor and the outlet part of the evaporator, and the lowermost part of the second low-pressure side refrigerant pipe has a lubricating oil in the refrigerant. Is provided for temporarily retaining the trap.

As a result, when the other evaporator is stopped and one of the evaporators is operated alone as the operation of the refrigeration cycle apparatus, the compressor lubricating oil in the refrigerant is caused by the weight of the second low-pressure side refrigerant pipe to be the highest. It will accumulate temporarily in the trap part provided in the lower part. And since the flow path cross-sectional area of a trap part becomes small with the lubricating oil collected, the flow rate by the suction of a compressor increases and it is made to make the compressor attract the lubricating oil collected in this trap part.
JP 2003-42599 A

  However, according to Patent Document 1, the trap portion provided in the second low-pressure side refrigerant pipe is an integral part provided with a bent portion in the second low-pressure side refrigerant pipe, and specifically, the second low-pressure side refrigerant pipe. The side refrigerant pipe is formed of a U-shaped U trap that is bent in the vertical direction.

  In other words, when the other evaporator is stopped and one evaporator is operated alone, the lubricating oil in the refrigerant flowing through the first low-pressure refrigerant pipe is provided in the second low-pressure refrigerant pipe. It is formed so as not to flow into the part.

  Accordingly, the suction of the compressor is performed until the liquid-phase lubricating oil by minute opening and closing from the expansion valve disposed in the other evaporator is sufficiently accumulated in the trap portion via the evaporator and the second low-pressure side refrigerant pipe. Does not work. That is, a considerable amount of elapsed time is required until the lubricating oil is sufficiently accumulated in the trap portion. Thereby, there is a problem that leads to a shortage of lubricating oil for the compressor.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a refrigeration cycle apparatus that can reliably return the lubricating oil that remains even when the refrigerant flow is stopped to the compressor.

In order to achieve the above object, the technical means described in claims 1 to 4 are employed. That is, in the first aspect of the invention, the compressor (16) that sucks, compresses, and discharges the refrigerant, the condenser (17) that condenses the high-pressure refrigerant, the condenser (17), and the compressor (16 And a plurality of evaporators (15, 33) arranged in parallel with each other to evaporate the low-pressure refrigerant and a plurality of evaporators (15, 33) from one evaporator (15) to the compressor (16) Lower position than the first low-pressure refrigerant pipe (26) connected to the suction part (16b), the suction part (16b) of the compressor (16), and the outlet part (33a) of at least one evaporator (33). And a second low-pressure side refrigerant pipe (39) joined from the evaporator (33) to the first low-pressure side refrigerant pipe (26) and connected to the suction portion (16b) of the compressor (16). In the refrigeration cycle apparatus provided,
The second low-pressure side refrigerant pipe (39) is provided with a trap portion (39b) for temporarily retaining lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe (26).

  According to the present invention, when at least one evaporator (33) is stopped and one evaporator (15) is operated alone as the operation of the refrigeration cycle apparatus, the first low-pressure refrigerant pipe (26) is circulated. The lubricating oil in the refrigerant to be stored temporarily accumulates in the trap part (39b) provided in the second low-pressure side refrigerant pipe (39). And since the flow passage cross-sectional area of the trap portion (39b) is reduced by the accumulated lubricating oil, the flow velocity by the suction of the compressor (16) increases, and the lubricating oil accumulated in the trap portion (39b) is removed from the compressor. (16).

  In this case, the lubricating oil accumulated in the evaporator (33) where the refrigerant flow is stopped and the second low-pressure side refrigerant pipe (39) is also returned to the compressor (16) by the suction of the compressor (16). Can do.

  The invention according to claim 2 is characterized in that the trap portion (39b) is provided immediately before joining the first low-pressure side refrigerant pipe (26) of the second low-pressure side refrigerant pipe (39). According to this invention, the suction action by the compressor (16) is increased by providing the trap part (39b) in the vicinity of the suction part (16b) of the compressor (16), and the return effect of the lubricating oil is improved. Can do.

  In the invention according to claim 3, the second low-pressure side refrigerant pipe (39) is provided with a rising portion (39c) having a predetermined height (H) on the upstream side of the trap portion (39b). It is characterized by. According to this invention, as the operation of the refrigeration cycle apparatus, when at least one evaporator (33) is stopped and one evaporator (15) is operated alone, the lubricating oil accumulated in the trap portion (39b) It does not flow into the upstream side of the second low-pressure side refrigerant pipe (39).

  In the invention according to claim 4, the second low-pressure side refrigerant pipe (39) temporarily traps the lubricating oil in the refrigerant whose downstream end flows through the first low-pressure side refrigerant pipe (26). It is characterized by being connected to the bottom surface side of the first low-pressure side refrigerant pipe (26) so as to flow into.

  According to this invention, since the lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe (26) is generally distributed along the bottom surface side of the first low-pressure side refrigerant pipe (26), the second low-pressure side By connecting the downstream end of the refrigerant pipe (39) to the bottom surface side of the first low-pressure side refrigerant pipe (26), it becomes easy to quickly accumulate the lubricating oil in the trap portion (39b). Therefore, the lubricant accumulated in the trap portion (39b), the evaporator (33), and the second low-pressure side refrigerant pipe (39) can be sucked into the compressor (16) by the lubricant accumulated quickly.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment mentioned later.

  Hereinafter, a refrigeration cycle apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram showing a vehicle-mounted form of the refrigeration cycle apparatus R. FIG. 2 is a schematic diagram showing the overall configuration of the refrigeration cycle apparatus R.

  In the present embodiment, the refrigeration cycle apparatus R is applied to a dual air conditioner type vehicle air conditioner having a plurality of air conditioning units 12 and 30 and is mounted on a minivan type passenger car.

  As shown in FIG. 1, the cabin 11 of the minivan type vehicle 10 has the second and third seats (rear seats) arranged behind the front seats (driver seat and passenger seat). A long space is formed in the longitudinal direction of the vehicle. Reference numeral 11 a shown in the figure is a floor surface of the passenger compartment 11.

  The vehicle air conditioner includes a front seat air conditioning unit 12 and a rear seat air conditioning unit 30. The front seat side air conditioning unit 12 is disposed inside the foremost instrument panel (not shown) in the passenger compartment 11 and air-conditions the area on the front seat side in the passenger compartment. The front seat air conditioning unit 12 has a case 13 that forms an air passage, and a blower 14 is disposed on the upstream side of the case 13.

  A front seat side evaporator 15 that is an evaporator of the refrigeration cycle apparatus R is disposed downstream of the blower 14 as a cooling heat exchanger for cooling the blown air. Here, the refrigeration cycle apparatus R has a well-known configuration and includes a compressor 16 driven by a vehicle engine (not shown) via an electromagnetic clutch 16a. The gas phase refrigerant is compressed to a high temperature and high pressure by the compressor 16, and the gas phase refrigerant discharged from the compressor 16 is introduced into a condenser 17, where the gas phase refrigerant is blown by a cooling fan (not shown). It exchanges heat with the outside air and liquefies and condenses.

  The refrigerant that has passed through the condenser 17 is separated into a liquid-phase refrigerant and a gas-phase refrigerant by the liquid receiver 18, and the liquid-phase refrigerant is stored in the liquid receiver 18. The liquid phase refrigerant from the liquid receiver 18 is expanded to low temperature and low pressure by a front seat side temperature type expansion valve 19 as an expansion valve, and this low temperature and low pressure refrigerant is absorbed by the front seat side evaporator 15 from the conditioned air and evaporated. It is like that.

  Incidentally, as is well known, the front seat side temperature type expansion valve 19 automatically adjusts the valve opening so that the refrigerant superheat degree at the outlet of the front seat side evaporator 15 is maintained at a predetermined value, and adjusts the refrigerant flow rate. is there.

  In the front seat evaporator 15, the evaporated gas refrigerant is again sucked into the compressor 16 and compressed. In the refrigeration cycle apparatus R, devices such as the compressor 16, the condenser 17, and the liquid receiver 18 are mounted in the engine room 20 on the front side from the passenger compartment 11.

  Reference numeral 25 shown in the figure is a first high-pressure side refrigerant pipe 25 that connects the liquid receiver 18 and the inlet side of the front seat side temperature type expansion valve 19, and reference numeral 26 shown in the figure is front seat side evaporation. This is a first low-pressure side refrigerant pipe 26 that connects the outlet side of the vessel 15 and the suction part 16 b of the compressor 16. The first high-pressure side refrigerant pipe 25 and the first low-pressure side refrigerant pipe 26 are disposed so as to penetrate a partition plate (not shown) that partitions the engine room 20 and the interior of the vehicle compartment 11.

  A branch portion 25a is provided in the middle of the first high-pressure side refrigerant pipe 25, and an underfloor high-pressure pipe 38, which is a second high-pressure side refrigerant pipe described later, is connected to the branch portion 25a. Further, a junction 26a is provided in the middle of the first low-pressure side refrigerant pipe 26, and an underfloor low-pressure pipe 39 that is a second low-pressure side refrigerant pipe described later is connected to the junction 26a. The branching portion 25a and the merging portion 26a are provided inside the engine room 20.

  Incidentally, in the front seat air conditioning unit 12, a temperature sensor 21 is disposed in the air blowing portion of the front seat evaporator 15, and the evaporator blowing air temperature (evaporator cooling temperature) Te detected by the temperature sensor 21. Is reduced to a predetermined value or less, the energization of the electromagnetic clutch 16a is cut off to stop the operation of the compressor 16, thereby preventing the front seat side evaporator 15 from being frosted.

  Further, a heater core (heating heat exchanger) 22 that heats the conditioned air with hot water from the vehicle engine is disposed on the downstream side of the air flow of the front seat evaporator 15, and a bypass is provided on the side of the heater core 22. A path 23 is formed. The air mix door 24 adjusts the air volume ratio between the warm air heated through the heater core 22 and the cool air passing through the bypass 23 to adjust the blown air temperature.

  Further, a defroster blowout opening, a face blowout opening, and a foot blowout opening (not shown) are opened at the downstream end of the front seat side air conditioning unit 12, and these openings are switched and opened by a blowout mode door (not shown). The conditioned air that has passed through each opening is blown toward the inner surface of the vehicle window glass, the head of the front seat occupant, and the feet.

  Next, the rear seat side air conditioning unit 30 is disposed in the rear part of the passenger compartment 11, for example, a side part of the rear seat, etc. so as to air-condition the rear seat side of the passenger compartment. A rear seat side blower 32 is provided upstream of the case 31 of the rear seat side air conditioning unit 30, and a rear seat side evaporator 33, which is an evaporator, is disposed downstream thereof. A heater core 34 that heats the conditioned air with hot water from the vehicle engine is disposed on the downstream side of the air flow of the rear seat evaporator 33.

  Then, the air volume ratio between the cool air cooled by the rear seat evaporator 33 and the warm air heated by the heater core 34 is adjusted by the bypass door 36 provided in the bypass passage 35 in the same manner as the front seat air conditioning unit 12. Then, the blowout air temperature is adjusted.

  A rear seat side temperature type expansion valve 37 as an expansion valve is provided at the refrigerant inlet of the rear seat side evaporator 33. The rear seat side temperature type expansion valve 37 is the same as the front seat side temperature type expansion valve 19.

  An underfloor high-pressure pipe 38 that is a second high-pressure side refrigerant pipe that connects the branch portion 25 a provided in the first high-pressure side refrigerant pipe 25 and the inlet side of the rear seat side temperature type expansion valve 37 is provided. Thus, the inlet side of the rear seat side temperature type expansion valve 37 is connected to the inlet side of the front seat side temperature type expansion valve 19 (downstream side of the condenser 17) via the underfloor high pressure pipe 38 and the first high pressure side refrigerant pipe 25. Connected to.

  In addition, an underfloor low-pressure pipe 39 that is a second low-pressure side refrigerant pipe that connects a merging portion 26 a provided in the first low-pressure side refrigerant pipe 26 and an outlet portion 33 a of the rear seat side evaporator 33 is provided. Thereby, the outlet 33a of the rear seat side evaporator 33 is connected to the outlet 15a of the front seat side evaporator 15 (the suction part 16b of the compressor 16) via the underfloor low pressure pipe 39 and the first low pressure side refrigerant pipe 26. It is connected to the.

  Therefore, the rear seat side temperature type expansion valve 37 and the rear seat side evaporator 33 are arranged in parallel with the front seat side temperature type expansion valve 19 and the front seat side evaporator 15 between the condenser 17 and the compressor 16. Has been. Since the underfloor high-pressure pipe 38 and the underfloor low-pressure pipe 39 are disposed in the underfloor space 40 formed below the floor surface 11a of the passenger compartment 11, a predetermined height L (for example, from the suction portion 16b of the compressor 16). , About 600 mm to 1000 mm). Similarly, it is a lower part than the outlet 33a of the rear seat side evaporator 33.

  A face blowout opening 41 and a blowout mode door 42 are arranged immediately downstream of the rear seat evaporator 33, and the cool air cooled by the rear seat evaporator 33 passes from the face blowout opening 41 to the rear seat face. It blows out from the ceiling outlet 43a through the duct 43 toward the head of the rear seat side occupant. Further, the warm air heated by the heater core 34 is blown out from the rear seat side foot outlet 44a toward the feet of the rear seat side occupant through the rear seat side foot duct 44.

  Here, the configuration of the underfloor low-pressure pipe 39 joined to the first low-pressure side refrigerant pipe 26 will be described with reference to FIG. As shown in FIG. 2, the underfloor low pressure pipe 39 corresponds to a low pressure side refrigerant pipe connected from the rear seat evaporator 33 to the suction portion 16 b of the compressor 16.

  The underfloor low pressure pipe 39 is connected from the outlet portion 33a of the rear seat side evaporator 33 toward the joining portion 26a of the first low pressure side refrigerant pipe 26, and as described above, the outlet portion 33a and the compression of the rear seat side evaporator 33 are compressed. The vertical position is lower than the suction part 16b of the machine 16, and the lowermost part 39a is formed in the middle.

  Then, in the vicinity of the merging portion 26a that is the downstream end of the underfloor low-pressure pipe 39, that is, immediately before the merging, a trap portion 39b for temporarily retaining the lubricating oil in the refrigerant, and a predetermined upstream side of the trap portion 39b. A rising portion 39c having a height H (for example, about 100 mm) is provided.

  The trap portion 39b and the rising portion 39c are formed integrally with the underfloor low-pressure pipe 39, and here are U-shaped ones that are bent in the vertical direction, so-called U traps. For example, if the trap part 39b and the rising part 39c are formed in a pipe shape, the underfloor low-pressure pipe 39 can be formed by bending.

  Further, one side of the U trap, that is, the downstream end of the trap portion 39 b is connected so as to open to the bottom surface side of the first low-pressure side refrigerant pipe 26. That is, the merging portion 26a provided in the first low-pressure side refrigerant pipe 26 is formed so that the bottom surface side of the first low-pressure side refrigerant pipe 26 is opened, and one side of the U trap is connected to the opening hole. Thereby, when there is no refrigerant flow in the underfloor low-pressure pipe 39, the lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe 26 can flow into the trap portion 39b by its own weight.

  Furthermore, on the other side of the U trap, that is, on the upstream side of the trap portion 39b, a rising portion 39c having an inverted U shape having a predetermined height H (for example, about 100 mm) is formed above. The upstream side of the rising portion 39c extends downward and is connected to the lowermost portion 39a. The lowest part 39a is provided substantially horizontally in the underfloor space 40 below the floor surface.

  Thereby, the lubricating oil of the refrigerant flowing through the first low-pressure side refrigerant pipe 26 can be accumulated in the trap portion 39b, and the lubricating oil accumulated in the trap portion 39b by forming the rising portion 39c having a predetermined height H. Does not flow toward the lowermost portion 39a of the underfloor low-pressure pipe 39.

  The trap portion 39b is preferably provided on the side close to the compressor 16. In other words, the joining portion 26a provided in the first low-pressure side refrigerant pipe 26 may be provided on the side close to the compressor 16, and the trap portion 39b may be provided in the vicinity of the joining portion 26a.

  Next, the operation of the refrigeration cycle apparatus R having the above configuration will be described. First, when both the front seat side air conditioning unit 12 and the rear seat side air conditioning unit 30 are operated, both the front and rear fans 14 and 32 are operated to blow air to both the air conditioning units 12 and 30. Then, when an air conditioner switch (compressor operation switch) on the operation panel (not shown) is turned on, the electromagnetic clutch 16a is energized and connected, so that the compressor 16 is driven by the vehicle engine.

  In the front seat air conditioning unit 12, the blown air is cooled and dehumidified by the front seat evaporator 15, and then reheated by the heater core 22. Further, the air mix door 24 arbitrarily adjusts the air volume ratio between the cold air and the hot air to adjust the temperature of the air blown into the passenger compartment.

  On the other hand, in the rear seat side air conditioning unit 30, the blow mode is switched between the face mode and the foot mode by the blow mode door 42, and in the face mode, the cold air cooled and dehumidified by the rear seat side evaporator 33 is used. 43 is blown out from the ceiling outlet 43a on the rear seat side to the rear seat side in the passenger compartment. In the foot mode, the blown air passes through the rear seat evaporator 33 and is then heated by the heater core 34 to become warm air. This warm air passes through the rear seat foot duct 44 from the rear seat foot outlet 44a. To blow out.

  By the way, when both the front and rear air conditioning units 12 and 30 are operated simultaneously as described above, the front and rear temperature expansion valves 19 and 37 correspond to the heat loads of the front and rear evaporators 15 and 33, respectively. Since the refrigerant having a flow rate corresponding to the heat load is always allowed to pass through the flow paths of the evaporators 15 and 33, the lubricating oil for the compressor stays in the underfloor low-pressure pipe 39 of the rear seat air conditioning unit 30 and the like. Never do.

  However, for example, when the occupant is only on the front seat side and no occupant is on the rear seat side, the rear seat side blower 32 is stopped by a switch operation on the operation panel. Thereby, the conditioned air is not blown to the rear seat side air conditioning unit 30 and the air conditioning action of the rear seat side air conditioning unit 30 is stopped, so that only the front seat side air conditioning unit 12 is in an independent operation state.

  During the front seat side independent operation, in the rear seat side air conditioning unit 30, the rear seat side temperature type expansion valve 37 repeatedly opens and closes, so that liquid-phase lubricating oil is contained in the rear seat side evaporator 33 and the rear seat side. It stays in the underfloor low-pressure pipe 39 on the outlet side of the evaporator 33.

  In particular, the underfloor low-pressure pipe 39 is disposed at a position lower by a predetermined amount L (for example, about 600 mm to 1000 mm) than the suction portion 16 b of the compressor 16, and is also lower than the outlet portion 33 a of the rear seat side evaporator 33. However, since it is arranged at a low position, the stagnation phenomenon of the lubricating oil in the underfloor low-pressure pipe 39 is likely to occur. That is, the lubricating oil flowing out from the rear seat side evaporator 33 is temporarily accumulated in the lowermost part 39a of the underfloor low-pressure pipe 39 by its own weight.

  However, in this embodiment, since the trap part 39b is provided at the downstream end of the underfloor low-pressure pipe 39, the lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe 26 temporarily accumulates in the trap part 39b by its own weight. It will follow.

  In other words, the lubricating oil that accumulates in the trap portion 39b is accumulated earlier than the lubricating oil that temporarily accumulates in the lowermost portion 39a of the underfloor low-pressure pipe 39. In this way, the flow passage cross-sectional area of the trap portion 39b is reduced by the lubricating oil on the first low-pressure side refrigerant pipe 26 side accumulated in the trap portion 39b, so that the flow velocity due to the suction of the compressor 16 increases. Lubricating oil in the trap portion 39 b can be sucked into the compressor 16, and lubricating oil staying in the lowermost portion 39 a of the underfloor low-pressure pipe 39 can be returned to the compressor 16.

  In the present embodiment, since the trap portion 39b is provided on the side near the compressor 16 in the underfloor low-pressure pipe 39, the suction action by the compressor 16 is further increased, and the return effect of the lubricating oil is improved. Can do.

  In addition, since the rising portion 39c having a predetermined height H is formed on the upstream side of the trap portion 39b, the lubricating oil accumulated in the trap portion 39b does not flow into the lowermost portion 39a of the underfloor low-pressure pipe 39. Absent. In addition, since the underfloor low-pressure pipe 39 is simply provided with a trap portion 39b and a rising portion 39c integrally formed by bending, it is possible to cope with an inexpensive manufacturing cost.

  According to the refrigeration cycle apparatus according to the above-described embodiment, the underfloor low-pressure pipe 39 that connects the joining portion 26a provided in the first low-pressure side refrigerant pipe 26 and the outlet portion 33a of the rear seat-side evaporator 33 is provided, At the downstream end of the underfloor low-pressure pipe 39, a trap portion 39b for temporarily retaining the lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe 26 is provided.

  Thereby, as operation of the refrigeration cycle apparatus, when one rear seat side evaporator 33 is stopped and the other front seat side evaporator 15 is operated alone, the refrigerant flowing through the first low pressure side refrigerant pipe 26 Is temporarily accumulated in the trap portion 39 b provided in the underfloor low-pressure pipe 39.

  And since the flow path cross-sectional area of the trap part 39b becomes small with the lubricating oil collected, the flow velocity by the suction | inhalation of the compressor 16 increases, and the lubricating oil collected in this trap part 39b can be made to attract | suck to the compressor 16. it can. In this case, the lubricating oil temporarily accumulated in the lower seat 39a of the rear seat side evaporator 33 and the underfloor low pressure pipe 39 where the refrigerant flow is stopped is also returned to the compressor 16 by the suction action of the compressor 16. Can do.

  Further, the trap portion 39b is provided immediately before joining the first low-pressure side refrigerant pipe 26 of the underfloor low-pressure pipe 39, so that the trap section 39b is provided in the vicinity of the compressor 16 so that the compressor 16 The suction action can be increased and the return effect of the lubricating oil can be improved.

  The underfloor low-pressure pipe 39 is provided with a rising portion 39c having a predetermined height H on the upstream side of the trap portion 39b, so that one of the rear seat side evaporators 33 is operated as the operation of the refrigeration cycle apparatus R. When the other front-seat evaporator 15 is stopped and operated independently, the lubricating oil accumulated in the trap portion 39 b does not flow into the upstream side of the underfloor low-pressure pipe 39.

  The underfloor low-pressure pipe 39 is connected to the bottom surface side of the first low-pressure side refrigerant pipe 26 so that the downstream end of the low-pressure pipe 39 temporarily flows the lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe 26 into the trap portion 39b. As a result, the lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe 26 is generally distributed along the bottom surface side of the first low-pressure side refrigerant pipe 26, so that the downstream end of the underfloor low-pressure pipe 39 is By being connected to the bottom surface side of the first low-pressure side refrigerant pipe 26, it becomes easy to quickly accumulate the lubricating oil in the trap portion 39b.

  Accordingly, the lubricant accumulated in the trap portion 39b, the rear seat-side evaporator 33, and the lowermost portion 39a of the underfloor low-pressure pipe 39 can be sucked into the compressor 16 by the lubricant that has been collected quickly.

(Other embodiments)
In the above embodiment, the refrigeration cycle apparatus R is applied to a dual air conditioner type vehicle air conditioner having two air conditioning units 12 and 30, but the vehicle air conditioner having two or more air conditioning units is used. It may be applied.

It is a schematic diagram which shows the vehicle mounting form of the refrigerating cycle apparatus R in one Embodiment of this invention. It is a mimetic diagram showing the whole refrigeration cycle device R composition in one embodiment of the present invention.

Explanation of symbols

15 ... Front seat side evaporator (evaporator)
DESCRIPTION OF SYMBOLS 16 ... Compressor 16b ... Suction part 17 ... Condenser 26 ... 1st low pressure side refrigerant | coolant piping 33 ... Rear seat side evaporator (evaporator)
33a ... Outlet part 39 ... Underfloor low pressure pipe (second low pressure side refrigerant pipe)
39b ... Trap part 39c ... Rising part

Claims (4)

A compressor (16) for sucking, compressing and discharging refrigerant;
A condenser (17) for condensing the high-pressure refrigerant;
A plurality of evaporators (15, 33) arranged in parallel between the condenser (17) and the compressor (16) to evaporate the low-pressure refrigerant;
A first low-pressure refrigerant pipe (26) connected from one of the evaporators (15) to the suction part (16b) of the compressor (16) among the plurality of evaporators (15, 33);
The first low-pressure side refrigerant is disposed at a position lower than the suction portion (16b) of the compressor (16) and the outlet portion (33a) of at least one of the evaporators (33), and from the evaporator (33). In the refrigeration cycle apparatus comprising the second low-pressure side refrigerant pipe (39) joined to the pipe (26) and connected to the suction portion (16b) of the compressor (16),
The second low pressure side refrigerant pipe (39) is provided with a trap portion (39b) for temporarily retaining lubricating oil in the refrigerant flowing through the first low pressure side refrigerant pipe (26). Refrigeration cycle equipment.   The refrigeration according to claim 1, wherein the trap part (39b) is provided immediately before joining the first low-pressure side refrigerant pipe (26) of the second low-pressure side refrigerant pipe (39). Cycle equipment.   The rising portion (39c) having a predetermined height (H) is provided in the second low-pressure side refrigerant pipe (39) on the upstream side of the trap portion (39b). Or the refrigerating-cycle apparatus of Claim 2.   The second low-pressure side refrigerant pipe (39) has the downstream end temporarily flowing the lubricating oil in the refrigerant flowing through the first low-pressure side refrigerant pipe (26) into the trap portion (39b). The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the refrigeration cycle apparatus is connected to a bottom surface side of one low-pressure side refrigerant pipe (26).

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