Cassette and vehicle air conditioning system

Abstract

Due to environmental concerns, refrigerants with low environmental impact are gaining attention. However, it is known that refrigerants used in air conditioning gradually leak over time. Furthermore, while flammable refrigerants such as propane have a low environmental impact, their use as refrigerants in vehicle air conditioning systems is problematic because the amount of refrigerant that can be charged is limited, leaving little margin for filling buffers such as accumulators. This leads to a decrease in refrigerant due to leakage, which degrades air conditioning performance. In addition, the flammability of the refrigerant poses safety problems such as fire and explosion during the process of replenishing the refrigeration unit. [Solution] In a refrigerant circuit equipped with a refrigerant unit integrating a compressor, condenser, evaporator, and accumulator, the accumulator has a connection part into which refrigerant can be filled, and a cassette is provided which stores refrigerant for filling and which is detachably configured to be attached to the connection part.

Description

Technical Field

[0001] The present invention relates to a cassette and a vehicle air conditioner.

Background Art

[0002] Conventionally, a small refrigerant unit in which devices (compressor, condenser, evaporator, expansion valve, refrigerant piping, etc.) constituting a refrigerant circuit are fixed to a plate or the like and integrated is known. Such a refrigerant unit is applied to, for example, a vehicle air conditioner.

[0003] By the way, in recent years, as a refrigerant used in such a refrigerant unit, a refrigerant with a low environmental load has been attracting attention in consideration of the environment (see, for example, Patent Document 1). For example, R290 made from propane has a zero ozone depletion coefficient, a very low global warming potential (GWP), and high energy efficiency, so it has been attracting attention as a refrigerant with a low environmental load.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, it is known that the refrigerant used for air conditioning gradually leaks over time. In addition, when using a flammable refrigerant such as propane as the refrigerant for a vehicle air conditioner, the amount of refrigerant enclosed and used is limited, so there is no margin in the filling amount to an accumulator or the like serving as a buffer, and there is a problem that a decrease in the refrigerant due to leakage deteriorates the air conditioning performance. Furthermore, there are safety problems such as fire and explosion during the operation of replenishing the refrigerant unit with the insufficient refrigerant because it is flammable.

[0006] The present invention was made to solve the aforementioned conventional technical problems, and aims to provide a cassette that can be used in vehicle air conditioning systems and allows for the comfortable and safe use of flammable refrigerants. [Means for solving the problem]

[0007] To solve these problems, the cassette according to the present invention has the following configuration.

[0008] A cassette is provided in a refrigerant circuit equipped with a refrigerant unit integrating a compressor, condenser, evaporator, and accumulator, wherein the accumulator has a connection part into which refrigerant can be charged, stores refrigerant for charging, and is configured to be detachable from the connection part. [Effects of the Invention]

[0009] According to the present invention, which has these characteristics, flammable refrigerants can be used comfortably and safely, making it possible to use refrigerants with a low environmental impact in vehicle air conditioning systems. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of a refrigerant unit according to an embodiment of the present invention. [Figure 2] This is a perspective view of a refrigerant unit according to an embodiment of the present invention. [Figure 3] This is a schematic diagram illustrating the replacement of a refrigerant charging cassette according to an embodiment of the present invention. [Figure 4] This is a detailed schematic diagram (1) showing the installation status of the refrigerant charging cassette according to an embodiment of the present invention. [Figure 5] This is a detailed schematic diagram (2) showing the installation status of the refrigerant charging cassette according to an embodiment of the present invention. [Figure 6] This is a detailed schematic diagram (3) showing the cassette mounting status for refrigerant charging according to an embodiment of the present invention. [Figure 7] This is a detailed schematic diagram (4) showing the installation status of the refrigerant charging cassette according to an embodiment of the present invention. [Figure 8] This is a side cross-sectional view of an accumulator according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. Each drawing is illustrative of an embodiment of the present invention and is not intended to limit the invention. In the following description, the same reference numerals in different figures indicate parts with the same function, and redundant explanations in each figure will be omitted as appropriate.

[0012] Furthermore, the dimensional relationships of each element in the drawings are for the purpose of facilitating understanding and are not intended to restrict the actual dimensional ratios.

[0013] Figure 1 is a perspective view of the refrigerant unit 3 as seen from the evaporator 16 and accumulator 60 side, and Figure 2 is a perspective view of the refrigerant unit 3 as seen from the compressor 10 and condenser 12 side. As shown in Figures 1 and 2, the refrigerant unit 3 comprises a refrigerant circuit connecting the compressor 10, condenser (heater) 12, expansion valves (pressure reducing devices) 14 and 15, evaporator (cooler) 16, accumulator 60, and flow path module 18 by refrigerant piping 21 to 26, and a support plate 19 that supports these components.

[0014] Here, the evaporator 16 and condenser 12 are refrigerant-heat transfer fluid heat exchangers that perform heat exchange between a refrigerant and a heat transfer fluid (e.g., water). They supply the heat from the refrigerant to the temperature-controlled object via a heat transfer fluid circuit (not shown) to perform air conditioning in the vehicle cabin and temperature control of in-vehicle equipment. In the examples in Figures 1 and 2, the heat transfer fluid circulating in the heat transfer fluid circuit flows into the evaporator 16 from the heat transfer fluid pipe 33, exchanges heat with the refrigerant in the evaporator 16, and flows out into the heat transfer fluid pipe 34. Similarly, the heat transfer fluid circulating in the heat transfer fluid circuit flows into the condenser 12 from the heat transfer fluid pipe 31, exchanges heat with the refrigerant in the condenser 12, and flows out into the heat transfer fluid pipe 32.

[0015] In the refrigerant unit 3, each device constituting the refrigerant circuit is connected as follows. The refrigerant suction port of the compressor 10 is connected to the accumulator 60 via the flow path module 18 by the refrigerant pipe 25. The refrigerant discharge port of the compressor 10 is connected to the refrigerant inlet of the condenser 12 by the refrigerant pipe 21 and is also connected to the flow path module 18 by the refrigerant pipe 26 branched from the refrigerant pipe 21.

[0016] Also, the refrigerant outlet of the condenser 12 is connected to the flow path module 18 by the refrigerant pipe 22. The refrigerant inlet of the evaporator 16 is connected to the flow path module 18 by the refrigerant pipe 23, and the refrigerant outlet of the evaporator 16 is connected to the accumulator 60 via the flow path module 18 by the refrigerant pipe 24.

[0017] The flow path module 18 has a manifold structure in which a plurality of refrigerant flow paths are integrally formed inside a metal body, and constitutes at least a part of the flow path through which the refrigerant circulates in the refrigerant circuit. Also, expansion valves 14 and 15 are connected to the upper surface on one end side of the flow path module 18, and the accumulator 60 is integrally attached to the side surface on the other end side.

[0018] The refrigerant flow path of the flow path module 18 includes a high-pressure flow path through which high-pressure refrigerant flows and a low-pressure flow path through which low-pressure refrigerant flows. That is, in one metal body, a high-pressure flow path that becomes high temperature as the refrigerant circulates and a low-temperature flow path that becomes low temperature coexist.

[0019] Therefore, in the flow path module 18, the high-pressure flow path is arranged so as to be concentrated in the high-pressure side region, the low-pressure flow path is arranged so as to be concentrated in the low-pressure side region, and the high-pressure side region and the low-pressure side region are partitioned so that the high-pressure flow path that becomes high temperature as the refrigerant circulates and the low-pressure flow path that becomes low temperature are not randomly mixed.

[0020] A connection section 62 is provided on the upper surface of the accumulator 60 to which a small cassette 40 containing refrigerant for charging is connected. The cassette 40 is connected to the accumulator 60 via the connection section 62. The cassette 40 for refrigerant charging is a small cylinder and can store, for example, approximately 20g or 40g of almost liquid refrigerant (including a predetermined proportion of gaseous phase). The refrigerant unit 3 is made compact, resulting in a short total refrigerant piping length. Furthermore, due to strict regulations required when using flammable gases, the total amount of refrigerant flowing through the entire refrigerant circuit in the refrigerant unit 3 is approximately 150g. Therefore, the amount of refrigerant stored in the cassette 40 is approximately 10% to 30% of the total amount of refrigerant in the refrigerant circuit, preferably 10% to 20%. In other words, the amount of refrigerant stored in the cassette 40 is such that overcharging of the refrigerant into the refrigerant circuit is suppressed. In addition, the cassette 40 is designed to be easily connected to and disconnected from the accumulator 60.

[0021] As shown in Figure 3, the accumulator 60 is provided with a connection part 62 that allows for easy attachment and detachment of the refrigerant charging cassette 40. When replacing the cassette 40 and recharging the refrigerant, the used cassette 40b is removed and a new cassette 40a is attached to the connection part 62 of the accumulator 60. The cassette 40 is used by being directly attached to the connection part 62 of the accumulator 60. Because the cassette 40 is compactly formed, it is possible to run the vehicle while using the vehicle air conditioning system 1 with the cassette 40 installed.

[0022] Next, the method of attaching the cassette 40 and the accumulator 60 will be explained using Figures 4 to 7. Note that the sealing structure, fastening structure, etc. of the connection part 62 between the cassette 40 and the accumulator 60 are omitted in each figure.

[0023] As shown in Figure 4, the cassette 40 comprises a cassette housing 42, a cylindrical valve body 46, a valve body opening / closing shaft 48, a threaded portion 50, connecting portions 52 and 54, and a protruding portion 56. The cassette housing 42 stores refrigerant under high pressure. The threaded portion 50 is formed at the tip of the valve body opening / closing shaft 48. The valve body 46 is prevented from rotating relative to the cassette housing 42 and is configured to move only in the axial direction of the valve body opening / closing shaft 48.

[0024] The valve body 46 is screwed onto the threaded portion 50, and by rotating the valve body opening / closing shaft 48, the threaded portion 50 rotates, causing the valve body 46 to move axially in conjunction. A cylindrical communication portion 54, smaller than or equal to the diameter of the valve body 46, is formed in the center of the bottom surface of the cassette housing 42. The cassette housing 42 communicates with the outside through this communication portion 54. In addition, an annular projection 56 is formed in the center of the bottom surface of the cassette housing 42, surrounding the outer edge of the communication portion 54. The inner diameter of this projection 56 is equal to the outer diameter of the valve body 46. The protruding portion 56 has a communication portion 52 formed therein that connects the inside and outside of the cassette 40 when the valve body 46 is moved upward. The valve body 46 is also formed to be movable in the axial direction of the valve body opening / closing shaft 48 within the range in which the outer surface of the valve body 46 is in contact with the inner surface of the protruding portion 56. Therefore, when the valve body 46 is moved upward and the communication portion 52 is in the open state, the refrigerant can be discharged from inside the cassette 40 to the outside, but in other cases, the structure prevents the refrigerant stored inside the cassette 40 from leaking to the outside.

[0025] The connection portion 62 on the accumulator 60 side, where the cassette 40 is attached and detached, comprises an accumulator upper housing 64, a differential pressure valve 66, an elastic member 68, a refrigerant introduction chamber 70, and communication portions 72 and 74. The elastic member 68 is, for example, a compression coil spring.

[0026] The differential pressure valve 66 is formed to be movable vertically, up to the upper inner wall surface of the refrigerant introduction chamber 70 and down to a position with a predetermined gap between it and the lower inner wall surface of the refrigerant introduction chamber 70. The inner diameter of the refrigerant introduction chamber 70 is formed to be equal to the outer diameter of the differential pressure valve 66. In addition, the differential pressure valve 66 has a communication portion 72 that extends in the vertical direction and through which the refrigerant can communicate. Therefore, the vertical space on either side of the differential pressure valve 66 is made communicable only by the communication portion 72.

[0027] The refrigerant introduction chamber 70 is equipped with a communication section 74 that communicates with the inside of the accumulator 60. The differential pressure valve 66 is subjected to a force acting towards the cassette 40 due to the biasing force of the elastic member 68 installed below the differential pressure valve 66. Therefore, when the vehicle air conditioning system 1 is stopped, the differential pressure valve 66 is pressed against the upper inner wall surface of the refrigerant introduction chamber 70 above. Consequently, the communication section 72 is closed at one end, as it is blocked by the refrigerant introduction chamber 70. Therefore, the refrigerant inside the accumulator 60 does not leak to the outside.

[0028] The cassette 40 and accumulator 60 are installed while the vehicle air conditioning system 1 is stopped. Figure 5 shows the cassette 40 and the accumulator 60 connected at the connection point 62, with the valve body 46 and differential pressure valve 66 still closed. Next, as shown in Figure 6, the valve body opening / closing shaft 48 is rotated to pull up the valve body 46 of the cassette 40 and open it, opening the communication point 52. When the vehicle air conditioning system 1 is started, the pressure inside the accumulator 60 becomes low, so the differential pressure valve 66 moves to the inside of the accumulator 60 and opens, and as shown by the dotted line in Figure 7, the high-pressure refrigerant inside the cassette 40 moves into the accumulator 60 via the refrigerant introduction chamber 70. In this way, refrigerant can be filled from the cassette 40 into the accumulator 60. When removing the cassette 40, the process is reversed.

[0029] Next, the accumulator 60 will be described. The accumulator according to the embodiment of the present invention is the same as the conventional configuration except that a connection part for the cassette 40 is provided at the top, as illustrated in Figure 8.

[0030] The accumulator 60 includes a refrigerant inlet 76 through which refrigerant flows from the evaporator 16 via a flow path module 18, a refrigerant introduction chamber 70 through which refrigerant filled from the cassette 40 flows into the accumulator 60 via a communication section 74, a refrigerant outlet 78 through which the refrigerant after gas-liquid separation is discharged, and a baffle plate 80. One end of the refrigerant outlet 78 opens above the gas-liquid interface 82, and the other end is connected to the compressor 10 via the flow path module 18. The baffle plate 80 is positioned between the gas-liquid interface 82 and the communication section 74 formed in the refrigerant inlet 76 and the refrigerant introduction chamber 70.

[0031] The accumulator 60 is a device that separates the refrigerant into gas and liquid phases after it has passed through the evaporator 16 and supplies the gaseous refrigerant to the compressor 10. In this embodiment, it also separates the refrigerant into gas and liquid phases after it has been filled from the cassette 40.

[0032] The incoming refrigerant collides with the baffle plate 80 and flows down. The liquid refrigerant is stored in the liquid refrigerant 86, while the gaseous refrigerant flows out from the gaseous refrigerant 84 through the refrigerant outlet 78 to the accumulator 60, and is drawn into the compressor 10 via the flow path module 18.

[0033] As explained above, in this invention, a small cassette 40 can be used for refrigerant charging, making refrigerant charging work safe and easy. In particular, in the refrigerant unit 3, since the total amount of refrigerant is small, an increase in the frequency of charging is expected, and thus the opportunities for dangerous charging work also increase. However, by using the cassette 40 of the present invention for refrigerant charging, these problems can be addressed. Furthermore, even when refrigerant charging is performed at dealerships or gas stations, there is no need to prepare large cylinders containing flammable gas for refrigerant charging, thus reducing the burden of safety management for storing large cylinders. In addition, the burden of environmental preparation in case of accidental ignition is also reduced.

[0034] Furthermore, according to the present invention, since a small cassette 40 can be used when charging the refrigerant, a conventional charging hose is unnecessary. Therefore, since no gas is purged from the charging hose, it is effective not only for flammable refrigerants but also for non-flammable refrigerants that have a high environmental impact.

[0035] Furthermore, since this invention uses a small cassette 40 for refrigerant charging, it is possible to operate the vehicle using the vehicle air conditioning system 1 while the cassette 40 remains attached to the accumulator 60. Therefore, a constant amount of refrigerant can always be automatically replenished from the cassette 40. Consequently, even if refrigerant leaks over time, the amount of refrigerant can always be maintained, thus maintaining a comfortable air-conditioned environment without degrading air conditioning performance. In addition, the risk of damaging the compressor 10 can be significantly reduced.

[0036] Furthermore, since the refrigerant is filled from the cassette 40 via the accumulator 60, the filled refrigerant is not directly drawn into the compressor 10, thus reducing the risk of damage to the compressor 10 due to liquid compression.

[0037] Furthermore, by changing the configuration of the connection part 62 of the accumulator 60, it becomes possible to operate the vehicle using the vehicle air conditioning system 1 even with the cassette 40 removed.

[0038] Furthermore, any changes to the design, etc., that do not depart from the spirit of the present invention are also included in this invention. [Explanation of symbols]

[0039] 1: Vehicle air conditioning system, 3: Refrigerant unit, 10: Compressor, 12: Condenser, 14, 15: Expansion valve, 16: Evaporator, 18: Flow module, 19: Support plate, 21-26: Refrigerant piping, 31-34: Heat transfer fluid piping, 40: Cassette, 40a: New cassette, 40b: Used cassette, 42: Cassette housing, 46: Valve body, 48: Valve body opening / closing shaft, 50: Screw portion, 52, 54: Connecting portion, 56: Protruding portion, 60: Accumulator, 62: Connection part, 64: Accumulator upper housing, 66: Differential pressure valve, 68: Elastic member, 70: Refrigerant inlet chamber, 72, 74: Communication section, 76: Refrigerant inlet, 78: Refrigerant outlet, 80: baffle plate, 82: gas-liquid interface, 84: gaseous refrigerant, 86: liquid refrigerant

Claims

1. In a refrigerant circuit equipped with a refrigerant unit that integrates a compressor, condenser, evaporator, and accumulator, The accumulator has a connection part into which a refrigerant can be filled, A refrigerant for filling is stored in a device that is detachably configured to attach to the connection part. A cassette characterized by the following features.

2. It has a refrigerant circuit through which the refrigerant circulates, A vehicle air conditioning system comprising a refrigerant unit integrating a compressor, condenser, evaporator, and accumulator that constitute the refrigerant circuit, The accumulator has a connection part into which the refrigerant can be filled, The aforementioned connection section allows for the attachment and detachment of a small cassette containing refrigerant for filling. A vehicle air conditioning system characterized by the following features.

3. The cassette comprises a cassette housing, a valve body, a shaft for moving the valve body, and a communication portion that connects the inside and outside of the cassette. The aforementioned communication portion is formed to be openable and closable by the movement of the valve body by the shaft, When the communication section is open, the inside of the cassette and the inside of the accumulator become able to communicate. When the aforementioned communication section is closed, the refrigerant will not leak from the inside of the cassette to the outside. The vehicle air conditioning system according to feature 2.

4. The aforementioned refrigerant is flammable. The vehicle air conditioning system according to claim 2 or 3, characterized by the features described above.

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