JP2009126300A - Refrigerating cycle device, and vehicular air conditioner having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle device capable of reducing a pressure loss of low-pressure refrigerant piping, and a vehicular air conditioner having the same. <P>SOLUTION: The refrigerating cycle device comprises a compressor 16, a condenser 17, a front seat side expansion valve 19, a front seat side evaporator 15, a rear seat side expansion valve 32 provided parallel to the front seat side expansion valve 19, a rear seat side evaporator 28 provided parallel to the front seat side evaporator 15, and refrigerant piping 57 for returning a refrigerant evaporated in the rear seat side evaporator 28 to the compressor 16. The low-pressure refrigerant piping 57 comprises a falling part 57a extending in a substantially-downward direction with one end side thereof connected to an outlet side of the rear seat side evaporator 28, a horizontal part 57b extending in a substantially-horizontal direction with one end side thereof connected to the other end side of the falling part 57a, and a rising part 57c with onde end side connected to the other end side of the horizontal part 57b, extending in a substantially-upward direction, and with the other end side connected to an inlet side of the compressor 16 or the low-pressure refrigerant piping 54. The diameter of the falling part 57a is larger than the diameter of the rising part 57c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus having two or more evaporators provided in parallel and a vehicle air conditioner including the same.

  Patent Document 1 discloses a so-called dual air conditioner type vehicle air conditioner that includes a front seat air conditioning unit that air-conditions the front seat side in the vehicle interior and a rear seat air conditioning unit that air-conditions the rear seat side. . In this vehicle air conditioner, the evaporator of the refrigeration cycle apparatus is provided independently in parallel on the front seat side and the rear seat side, respectively, and the compressor and the condenser are commonly used on the front seat side and the rear seat side. ing.

In addition, this vehicle air conditioner prevents the lubricating oil that circulates with the refrigerant in the refrigeration cycle from accumulating in the rear seat evaporator and low-pressure refrigerant piping when the front seat air conditioning unit is operating alone. Therefore, lubricating oil recovery control is performed. In this lubricating oil recovery control, the forced intermittent operation of the compressor is performed at predetermined time intervals when the front seat air conditioning unit is operating independently and the compressor is operating for a long time. It has become. As a result, it is possible to allow a flow of refrigerant to flow into the rear-seat evaporator, so that the lubricating oil accumulated in the rear-seat evaporator and the low-pressure refrigerant pipe returns to the compressor suction side by the refrigerant flow. It has become.
JP 2000-283576 A

  In recent years, in order to more reliably prevent the lubricating oil from accumulating in the rear seat side low-pressure refrigerant pipe, the pipe diameter of the rear seat-side low-pressure refrigerant pipe may be set relatively small as a whole. Thereby, since the flow velocity of the refrigerant in the low-pressure refrigerant pipe is increased, the lubricating oil easily returns to the compressor side together with the refrigerant.

  However, when the pipe diameter of the low pressure refrigerant pipe on the rear seat side becomes small, the pressure loss of the low pressure refrigerant pipe on the rear seat side becomes large. Therefore, at the time of dual operation in which both the front seat side and rear seat side air conditioning units operate, a sufficient flow rate of refrigerant cannot be flowed to the rear seat side, and the cooling capacity of the rear seat side air conditioning unit is reduced. The problem arises.

  The objective of this invention is providing the refrigeration cycle apparatus which can reduce the pressure loss of a low pressure refrigerant | coolant piping, and a vehicle air conditioner provided with the same.

  In order to achieve the above object, the present invention employs the following technical means.

  The invention described in claim 1 includes a compressor (16) that compresses and discharges a refrigerant, a condenser (17) that cools and condenses the refrigerant discharged from the compressor (16), and a condenser (17). A first decompression means (19) for decompressing and expanding the condensed refrigerant, a first evaporator (15) for evaporating the refrigerant decompressed and expanded by the first decompression means (19), and a first evaporator (15 ) And the first refrigerant pipe (54) for returning the refrigerant evaporated in the compressor (16) to the first decompression means (19), and decompress the refrigerant condensed in the condenser (17) under reduced pressure. A second depressurization means (32), a second evaporator (28) provided in parallel with the first evaporator (15) and evaporating the refrigerant decompressed and expanded by the second depressurization means (32); And a second refrigerant pipe (57) for returning the refrigerant evaporated by the second evaporator (28) to the compressor (16). The second refrigerant pipe (57) has one end connected to the outlet side of the second evaporator (28) and extending substantially downward, and the other end of the falling part (57a). One end side is connected to the horizontal portion (57b) extending generally in the horizontal direction, and one end side is connected to the other end side of the horizontal portion (57b) and extends generally upward, and the inlet side of the compressor (16) or the first side A rising portion (57c) having the other end connected to the refrigerant pipe (54), and the diameter of the falling portion (57a) is larger than the diameter of at least a part of the rising portion (57c). It is a feature.

  Thereby, since the pressure loss in the fall part (57a) can be reduced, the pressure loss as the whole 2nd refrigerant | coolant piping (57) can be reduced. At the falling part (57a), the refrigerant and the lubricating oil flow in a direction that follows gravity. Therefore, even if the pipe diameter of the falling part (57a) is large, the return amount of the lubricating oil to the compressor (16) is insufficient. That is less.

  On the other hand, by reducing the pipe diameter of at least a part of the rising portion (57c), the flow rate of the refrigerant at the rising portion (57c) can be improved, so that an insufficient return amount of lubricating oil to the compressor (16) is prevented. it can.

  The invention described in claim 2 is characterized in that the tube diameter of the falling portion (57a) is larger than the overall tube diameter of the rising portion (57c).

  By making the pipe diameter of almost the entire rising portion (57c) relatively small, the flow rate of the refrigerant at the rising portion (57c) can be improved, so that the amount of return of lubricating oil to the compressor (16) is more reliably ensured. Can be prevented.

  The invention according to claim 3 is characterized in that the tube diameter of the falling portion (57a) is larger than the tube diameter of the horizontal portion (57b).

  By making the pipe diameter of the horizontal portion (57b) relatively small, the flow rate of the refrigerant in the horizontal portion (57b) can be improved, so that the shortage of the return amount of the lubricating oil to the compressor (16) can be prevented more reliably.

  The invention according to claim 4 is characterized in that the tube diameter of the horizontal portion (57b) is larger than the tube diameter of the rising portion (57c).

  Since the pressure loss in the horizontal portion (57b) can be reduced by relatively increasing the tube diameter of the horizontal portion (57b), the pressure loss of the second refrigerant pipe (57) as a whole can be reduced. In the horizontal portion (57b), the refrigerant and the lubricating oil flow in a direction substantially perpendicular to the direction of gravity, so that the amount of return of the lubricating oil to the compressor (16) is insufficient even if the pipe diameter of the horizontal portion (57b) is large. There is little risk of losing.

  The invention according to claim 5 is characterized in that the diameter of the falling portion (57a) is larger than the diameter of the first refrigerant pipe (54).

  Since the pressure loss at the falling portion (57a) can be reduced by further increasing the pipe diameter of the falling portion (57a), the pressure loss of the second refrigerant pipe (57) as a whole can be reduced.

  The invention described in claim 6 is characterized in that the pipe diameter of the horizontal portion (57b) is larger than the pipe diameter of the first refrigerant pipe (54).

  Since the pressure loss in the horizontal portion (57b) can be reduced by further increasing the tube diameter of the horizontal portion (57b), the pressure loss of the entire second refrigerant pipe (57) can be reduced.

  According to the seventh aspect of the present invention, the second evaporator (28) is connected to one end side of the falling part (57a), and the outlet (28a) allows the refrigerant to flow downward from the falling part (57a). It is characterized by having.

  As a result, the refrigerant and lubricating oil in the second evaporator (28) are likely to flow out toward the falling portion (57a), so that the refrigerant and lubricating oil accumulate in the second evaporator (28). Can be prevented.

  Invention of Claim 8 is a vehicle air conditioner mounted in a vehicle (10), Comprising: The refrigeration cycle apparatus of the said invention and the front seat side in the compartment (11) of a vehicle (10) are air-conditioned. A front seat side air conditioning unit (12) and a rear seat side air conditioning unit (25) for air conditioning the rear seat side in the passenger compartment (11) are provided, and the first evaporator (15) is a front seat side air conditioning unit (12 ) And the second evaporator (28) is arranged in the rear seat air conditioning unit (25).

  Thereby, since the refrigerant | coolant of sufficient flow volume can be poured also to the backseat side, the cooling capacity of a backseat side air conditioning unit (25) can be improved.

  In addition, the code | symbol in the bracket | parenthesis of each said means has shown an example of the corresponding relationship with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing an arrangement configuration when the refrigeration cycle apparatus and the vehicle air conditioner in the present embodiment are applied to a minivan type passenger car. As shown in FIG. 1, a front seat (driver seat and front passenger seat) and rear second and third row seats (rear seats) are arranged in a passenger compartment 11 of a minivan type vehicle 10. Has been. The vehicle compartment 11 forms a relatively long space in the vehicle front-rear direction.

  The vehicle air conditioner has a front seat side air conditioning unit 12 that air-conditions a region on the front seat side in the passenger compartment 11. The front seat air conditioning unit 12 is disposed inside the foremost instrument panel (not shown) in the passenger compartment 11. The front seat air conditioning unit 12 has a case 13 that forms an air passage. A blower 14 is disposed upstream of the case 13. The blower 14 blows the inside air or the outside air switched and introduced from an inside / outside air switching box (not shown) toward the vehicle compartment 11 side. On the downstream side of the air flow of the blower 14, a front seat side evaporator (first evaporator) 15 described later is arranged as a cooling heat exchanger for cooling the blown air. A temperature sensor 21 for detecting the evaporator outlet temperature is disposed at the air outlet of the front seat evaporator 15.

  A heater core 22 that heats the conditioned air by heat exchange with cooling water (hot water) that cools the vehicle engine (not shown) is disposed on the downstream side of the air flow of the front seat evaporator 15. A bypass passage 23 is formed on the side of the heater core 22. A plate-like air mix door 24 is disposed adjacent to the heater core 22 so as to be rotatable. By selecting the rotation position of the air mix door 24, the air volume ratio between the warm air heated through the heater core 22 and the cold air passing through the bypass passage 23 is adjusted, and the blown air temperature is adjusted.

  A defroster opening, a face opening, and a foot opening (not shown) are opened at the downstream end of the front seat air conditioning unit 12. These openings are opened and closed by a blowout mode door (not shown). The conditioned air that has passed through the defroster opening is blown to the inner surface of the vehicle window glass, the conditioned air that has passed through the face opening is blown to the upper body side of the front seat occupant, and the conditioned air that has passed through the foot opening is It is blown out to the lower body side.

  The vehicle air conditioner also includes a rear seat air conditioning unit 25 that air-conditions the rear seat area in the passenger compartment 11. The rear seat side air conditioning unit 25 is disposed in a rear portion of the passenger compartment 11, for example, in a side portion of the rear seat. In the case 26 of the rear seat side air conditioning unit 25, a blower 27 that sucks and blows in the inside air is provided. On the downstream side of the air flow of the blower 27, a rear seat side evaporator (second evaporator) 28 described later is disposed.

  A heater core 29 that heats the conditioned air by heat exchange with warm water from the vehicle engine is disposed on the downstream side of the rear seat side evaporator 28 in the air flow. A bypass passage 30 is formed on the side of the heater core 29. A plate-like cold air bypass door 31 is disposed adjacent to the heater core 29 so as to be rotatable. The bypass passage 30 is opened and closed by the cold air bypass door 31 based on the blowing mode and the air volume level of the rear seat air conditioning unit 25.

  A rear-seat-side face opening 36 and a blow-out mode door 37 are disposed downstream of the rear-seat evaporator 28 and downstream of the heater core 29. The rear seat face opening 36 is opened and closed by a blow mode door 37 based on the blow mode of the rear seat air conditioning unit 25. A rear seat face duct 38 is connected to the rear seat face opening 36. A ceiling outlet 38 a is provided at the downstream end of the rear seat side face duct 38. Thus, the cool air cooled by the rear seat evaporator 28 and passed through the rear seat face opening 36 is blown out toward the upper body side such as the head of the rear seat occupant through the ceiling outlet 38a. It has become.

  A rear seat side foot duct 39 is connected to the downstream side of the air flow of the heater core 29 and the bypass passage 30. A rear seat-side foot outlet 39 a is provided at the downstream end of the rear seat-side foot duct 39. As a result, the warm air heated by the heater core 29 is blown out toward the lower body side such as the feet of the rear seat occupant through the rear seat foot outlet 39a.

  FIG. 2 is a schematic diagram showing a schematic configuration of the refrigeration cycle apparatus in the present embodiment. The vertical direction in FIG. 2 generally represents the vertical vertical direction. Moreover, in FIG. 2, the flow direction of a refrigerant | coolant is represented by the arrow. As shown in FIG. 2, the refrigeration cycle apparatus R includes a compressor 16 driven by a vehicle engine via an electromagnetic clutch 16a. The compressor 16 compresses and discharges the refrigerant to a high temperature and a high pressure. The discharge side of the compressor 16 is connected to the condenser 17 via, for example, an aluminum high-pressure refrigerant pipe 50. The gas refrigerant discharged from the compressor 16 flows into the condenser 17 and is cooled and condensed by heat exchange with the outside air blown by a cooling fan (not shown).

  The outlet side of the condenser 17 is connected to the liquid receiver 18 (not shown in FIG. 2) via a high-pressure refrigerant pipe 51 made of aluminum, for example. The refrigerant condensed in the condenser 17 flows into the liquid receiver 18 and is separated into a liquid phase refrigerant and a gas phase refrigerant. Among these, the liquid phase refrigerant is stored in the liquid receiver 18. The outlet side of the liquid receiver 18 is connected to a temperature type front seat side expansion valve (first decompression means) 19 via, for example, an aluminum high-pressure refrigerant pipe 52. The liquid refrigerant flowing from the liquid receiver 18 into the front seat side expansion valve 19 is decompressed and becomes a low-pressure gas-liquid two-phase refrigerant.

  The outlet side of the front seat side expansion valve 19 is connected to the front seat side evaporator 15 via, for example, a low-pressure refrigerant pipe 53 made of aluminum. The low-pressure refrigerant decompressed by the front seat side expansion valve 19 flows into the front seat side evaporator 15 and absorbs heat from the conditioned air to evaporate. The outlet side of the front seat evaporator 15 is connected to the suction side (inlet side) of the compressor 16 via, for example, a low-pressure refrigerant pipe (first refrigerant pipe) 54 made of aluminum. The low-pressure refrigerant evaporated in the front seat evaporator 15 returns to the compressor 16 and is compressed again.

  Here, the front seat side 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. Therefore, the front seat side expansion valve 19 includes a temperature sensing part that senses the refrigerant temperature at the outlet of the front seat side evaporator 15, a first pressure chamber to which a pressure corresponding to the refrigerant temperature sensed by the temperature sensing part is applied, A second pressure chamber to which the refrigerant pressure (cycle low pressure) of the front seat evaporator 15 is applied, and a diaphragm partitioning the first and second pressure chambers, and the pressure difference and spring force between the first and second pressure chambers Accordingly, the diaphragm and the valve body are displaced to adjust the refrigerant flow rate.

  In the refrigeration cycle apparatus R, devices such as the compressor 16, the condenser 17, and the liquid receiver 18 are mounted in an engine room (engine compartment) 20 on the front side of the vehicle compartment 11. When the evaporator blown air temperature detected by the temperature sensor 21 falls below a predetermined value, the air conditioning ECU (not shown) cuts off the energization of the electromagnetic clutch 16a and stops the operation of the compressor 16. Thereby, the frost of the front seat side evaporator 15 is prevented.

  The refrigeration cycle apparatus R includes a rear seat side expansion valve (second decompression means) 32 and a rear seat side evaporator 28 provided in parallel with the front seat side expansion valve 19 and the front seat side evaporator 15, respectively. ing. The rear seat side expansion valve 32 is connected to the outlet side of the liquid receiver 18 through a high-pressure refrigerant pipe 55 made of, for example, aluminum that branches from the high-pressure refrigerant pipe 52 at a branch point 60. The high-pressure refrigerant pipe 55 passes through the floor lower part 35 below the floor surface 11 a of the passenger compartment 11. The rear seat side expansion valve 32 is the same as the front seat side expansion valve 19 and is adapted to depressurize the high-temperature and high-pressure liquid refrigerant from the liquid receiver 18 into a low-temperature and low-pressure gas-liquid two-phase refrigerant. Yes. The rear seat side expansion valve 32 adjusts the valve opening and adjusts the refrigerant flow rate so that the degree of refrigerant superheat at the outlet of the rear seat evaporator 28 is maintained at a predetermined value.

  The rear seat side evaporator 28 is connected to the outlet side of the rear seat side expansion valve 32 via a low pressure refrigerant pipe 56 made of, for example, aluminum. The low-pressure refrigerant decompressed by the rear seat side expansion valve 32 flows into the rear seat evaporator 28 and absorbs heat from the conditioned air to evaporate. The front seat evaporator 15 has, for example, an outflow port 28b provided sideways. The outflow port 28 b is connected to one end side of a low-pressure refrigerant pipe (second refrigerant pipe) 57 made of, for example, aluminum that passes through the lower floor 35. The other end of the low-pressure refrigerant pipe 57 is connected to the low-pressure refrigerant pipe 54 at a junction 61. As a result, the low-pressure refrigerant evaporated in the rear seat evaporator 28 flows out from the outlet 28b, returns to the compressor 16 via the low-pressure refrigerant pipes 57 and 54, and is compressed again.

  Here, the low-pressure refrigerant pipe 57 includes a falling portion 57a that extends substantially downward from the rear portion of the passenger compartment 11 to the lower floor portion 35, a horizontal portion 57b that extends substantially horizontally in the lower floor portion 35, and the engine room 20 from the lower floor portion 35. It has three parts roughly divided into a rising part 57c extending generally upward. In the present embodiment, the falling portion 57a is a portion from the outlet side of the rear seat evaporator 28 to the falling point 62, and the horizontal portion 57b is a portion from the falling point 62 to the rising point 63. Reference numeral 57 c denotes a portion from the rising point 63 to the junction 61.

  The horizontal portion 57b is disposed at a portion lower than the junction 61 by a predetermined height L (for example, about 600 mm). In this embodiment, the distance between the falling point 62 and the rising point 63 of the horizontal portion 57b is D, and the difference between the maximum height and the minimum height between the falling point 62 and the rising point 63 is Δh. Then, the inclination (Δh / D) of the horizontal portion 57b is allowed to about 10%. For example, in the vehicle 10 having a distance D of about 2 to 3 m, a height change of about 300 mm or less is allowed between the falling point 62 and the rising point 63.

  The diameters of the falling part 57a and the horizontal part 57b of the low-pressure refrigerant pipe 57 are larger than the pipe diameter of the rising part 57c (FIG. 2 schematically shows the difference in the pipe diameters of the low-pressure refrigerant pipe 57. ing). For example, the falling portion 57a and the horizontal portion 57b are configured by a 5/8 inch tube (D5 / 8), and the rising portion 57c is configured by a 1/2 inch tube (D1 / 2).

  In the present embodiment, the lubricating oil recovery control disclosed in, for example, Patent Document 1 is performed in order to prevent the lubricating oil stagnation phenomenon that the lubricating oil circulating in the refrigeration cycle together with the refrigerant accumulates in the low-pressure refrigerant pipe 57 or the like. . That is, when the rear seat side air conditioning unit 25 is stopped, the front seat side air conditioning unit 12 is operating alone, and the compressor 16 is continuously operated for a long time, the compression is performed by the control of the air conditioning ECU. The forced intermittent operation of the machine 16 is performed at predetermined time intervals. Thereby, since the low pressure in the refrigeration cycle fluctuates, the rear seat side expansion valve 32 is forcibly opened, so that it is possible to cause a flow of refrigerant to flow into the rear seat side evaporator 28. Therefore, the lubricating oil accumulated in the low-pressure refrigerant pipe 57 can be returned to the suction side of the compressor 16 by the refrigerant flow.

  Here, in the rising portion 57c, the flow direction is a direction against gravity, and therefore, the lubricating oil is difficult to return to the compressor 16 side. In this embodiment, since the pipe diameter of the rising portion 57c is relatively small, the flow rate of the refrigerant at the rising portion 57c can be increased. Therefore, the flow of the lubricating oil is promoted by the refrigerant flow, and the lubricating oil can be returned more reliably to the compressor 16 side. In the present embodiment, the overall pipe diameter of the rising portion 57c is reduced. However, if the pipe diameter of at least a part of the rising portion 57c is reduced, the flow rate of the refrigerant in the vicinity of the small pipe diameter portion of the rising portion 57c is increased. Therefore, the shortage of the return amount of the lubricating oil to the compressor 16 side can be improved.

  In the present embodiment, since the pipe diameters of the falling part 57a and the horizontal part 57b are relatively large, the pressure loss of the low-pressure refrigerant pipe 57 is reduced as compared with the configuration in which the pipe diameter of the entire low-pressure refrigerant pipe 57 is reduced. Can be reduced. Accordingly, since the refrigerant flow rate flowing to the rear seat side can be sufficiently secured even in the dual operation in which both the front seat air conditioning unit 12 and the rear seat air conditioning unit 25 are operated, the cooling capacity of the rear seat air conditioning unit 25 is reduced. Can be prevented.

  The refrigerant and the lubricating oil when the lubricating oil recovery control is performed flow in a direction according to gravity at the falling portion 57a, and flow in a direction substantially perpendicular to the direction of gravity at the horizontal portion 57b. For this reason, in the fall part 57a and the horizontal part 57b, even if the flow rate of a refrigerant | coolant is comparatively low, there is little possibility that the return amount of lubricating oil to the compressor 16 will be insufficient.

  FIG. 3 is a schematic diagram showing a first modification of the refrigeration cycle apparatus in the present embodiment. As shown in FIG. 3, in this modification, the tube diameters of the rising portion 57c and the horizontal portion 57b are smaller than the tube diameter of the falling portion 57a. Thereby, since the flow rate of the refrigerant can be increased in the horizontal portion 57b where the refrigerant and the lubricating oil hardly flow compared to the falling portion 57a, the configuration shown in FIG. 2 (referred to as “basic configuration” in the present specification for convenience). ) Can be reliably returned to the compressor 16 side.

  FIG. 4 is a schematic diagram showing a second modification of the refrigeration cycle apparatus in the present embodiment. As shown in FIG. 4, in the present modification, the falling portion 57a and the horizontal portion 57b are configured by a 3/4 inch tube (D3 / 4) having a tube diameter larger than the basic configuration. It is larger than the pipe diameter of the pipe 54. Thereby, the pressure loss in the fall part 57a and the horizontal part 57b can further be reduced rather than a basic composition.

  FIG. 5 is a schematic diagram showing a third modification of the refrigeration cycle apparatus in the present embodiment. As shown in FIG. 5, in this modification, the tube diameter of the horizontal portion 57b is smaller than the tube diameter of the falling portion 57a as compared to the second modification. Thereby, since the flow rate of the refrigerant | coolant in the horizontal part 57b can be raised, lubricating oil can be reliably returned to the compressor 16 side rather than the 2nd modification.

  FIG. 6 is a schematic diagram showing a fourth modification of the refrigeration cycle apparatus in the present embodiment. As shown in FIG. 6, in this modification, the tube diameter of the rising portion 57c is smaller than the tube diameter of the horizontal portion 57b, and the tube diameter of the falling portion 57a is larger than the tube diameter of the horizontal portion 57b. It has become. Thereby, the lubricating oil can be reliably returned to the compressor 16 side, and the pressure loss of the low-pressure refrigerant pipe 54 can be reduced.

(Second Embodiment)
Next, a refrigeration cycle apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a schematic diagram showing a schematic configuration of the refrigeration cycle apparatus in the present embodiment. As shown in FIG. 7, the present embodiment is characterized in that the rear seat side evaporator 28 has an outlet 28 a that allows the refrigerant to flow downward with respect to the falling portion 57 a. Here, “downward” means vertically downward from the horizontal.

  According to the present embodiment, the same effect as that of the first embodiment can be obtained, and the refrigerant and the lubricating oil in the rear seat side evaporator 28 can be easily discharged to the falling portion 57a side. Therefore, it is possible to prevent refrigerant and lubricating oil from accumulating in the rear seat evaporator 28, and to avoid the stagnation of the lubricating oil in the rear seat evaporator 28 without performing the lubricating oil recovery control. Become.

(Other embodiments)
In the above embodiment, the portion of the low-pressure refrigerant pipe 57 where the pipe diameter changes is the falling point 62 or the rising point 63, but the pipe diameter changes in the middle of the falling part 57a, the horizontal part 57b, or the rising part 57c. It may be.

  In the above embodiment, the low-pressure refrigerant pipe 57 joins the low-pressure refrigerant pipe 54 at the junction 61 and is connected to the suction side of the compressor 16 via the low-pressure refrigerant pipe 54. 16 may be directly connected to the suction side.

  Furthermore, in the said embodiment, although the refrigerating cycle apparatus which has two evaporators (front seat side evaporator 15 and rear seat side evaporator 28) provided in parallel was mentioned as an example, a refrigerating cycle apparatus is provided in parallel. Three or more evaporators may be provided. In this case, in the low-pressure refrigerant pipe connecting the outlet side of at least one evaporator and the compressor, the diameter of the falling part is made larger than the diameter of at least a part of the rising part.

It is a schematic diagram which shows the arrangement configuration of the refrigeration cycle apparatus and the vehicle air conditioner in the first embodiment. It is a schematic diagram which shows schematic structure of the refrigerating-cycle apparatus in 1st Embodiment. It is a schematic diagram which shows the 1st modification of the refrigeration cycle apparatus in 1st Embodiment. It is a schematic diagram which shows the 2nd modification of the refrigerating-cycle apparatus in 1st Embodiment. It is a schematic diagram which shows the 3rd modification of the refrigerating-cycle apparatus in 1st Embodiment. It is a schematic diagram which shows the 4th modification of the refrigeration cycle apparatus in 1st Embodiment. It is a schematic diagram which shows schematic structure of the refrigerating-cycle apparatus in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Car interior 11a Floor 12 Front seat side air-conditioning unit 14, 27 Blower 15 Front seat side evaporator (1st evaporator)
16 Compressor 17 Condenser 18 Liquid receiver 19 Front seat side expansion valve (first decompression means)
20 Engine room 25 Rear seat air conditioning unit 28 Rear seat evaporator (second evaporator)
28a Outlet 32 Rear seat side expansion valve (second decompression means)
35 Lower floor 54 Low-pressure refrigerant pipe (first refrigerant pipe)
57 Low-pressure refrigerant piping (second refrigerant piping)
57a Falling portion 57b Horizontal portion 57c Rising portion 60 Branch point 61 Junction point 62 Falling point 63 Rising point

Claims (8)

A compressor (16) for compressing and discharging the refrigerant;
A condenser (17) for cooling and condensing the refrigerant discharged from the compressor (16);
First decompression means (19) for decompressing and expanding the refrigerant condensed in the condenser (17);
A first evaporator (15) for evaporating the refrigerant decompressed and expanded by the first decompression means (19);
A first refrigerant pipe (54) for returning the refrigerant evaporated in the first evaporator (15) to the compressor (16);
A second decompression means (32) provided in parallel with the first decompression means (19) and decompressing and expanding the refrigerant condensed in the condenser (17);
A second evaporator (28) which is provided in parallel with the first evaporator (15) and evaporates the refrigerant decompressed and expanded by the second decompression means (32);
A second refrigerant pipe (57) for returning the refrigerant evaporated in the second evaporator (28) to the compressor (16),
The second refrigerant pipe (57) has one end connected to the outlet side of the second evaporator (28) and extends substantially downward, and includes a falling part (57a) extending in a downward direction and the falling part (57a). A horizontal portion (57b) having one end connected to the end side and extending in a generally horizontal direction, and one end side connected to the other end of the horizontal portion (57b) and extending generally upward, the inlet side of the compressor (16) Or a rising portion (57c) having the other end connected to the first refrigerant pipe (54),
The refrigeration cycle apparatus characterized in that a pipe diameter of the falling part (57a) is larger than a pipe diameter of at least a part of the rising part (57c).   2. The refrigeration cycle apparatus according to claim 1, wherein a tube diameter of the falling portion (57 a) is larger than a substantially entire tube diameter of the rising portion (57 c).   The refrigeration cycle apparatus according to claim 1 or 2, wherein a tube diameter of the falling portion (57a) is larger than a tube diameter of the horizontal portion (57b).   The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein a tube diameter of the horizontal portion (57b) is larger than a tube diameter of the rising portion (57c).   The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein a pipe diameter of the falling portion (57a) is larger than a pipe diameter of the first refrigerant pipe (54).   The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein a pipe diameter of the horizontal portion (57b) is larger than a pipe diameter of the first refrigerant pipe (54).   The second evaporator (28) is connected to one end side of the falling part (57a) and has an outlet (28a) through which the refrigerant flows downward with respect to the falling part (57a). The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein: A vehicle air conditioner mounted on a vehicle (10),
The refrigeration cycle apparatus according to any one of claims 1 to 7,
A front seat side air conditioning unit (12) for air conditioning the front seat side in the passenger compartment (11) of the vehicle (10);
A rear seat side air conditioning unit (25) for air conditioning the rear seat side in the passenger compartment (11),
The first evaporator (15) is disposed in the front seat air conditioning unit (12),
The vehicular air conditioner, wherein the second evaporator (28) is disposed in the rear seat air conditioning unit (25).

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