Silencing device for air conditioner

Abstract

The invention provides a silencer for an air conditioner, which can use CO2 refrigerant. An air-conditioning silencer (50), which is provided to a pipe of an air-conditioning refrigerant containing CO2, is provided with a silencer body (52) that has: a cylindrical body (54) that does not have a seam in the circumferential direction; and a pair of cover bodies (56) which are hermetically welded on the two axial ends of the cylinder body (54) in order to seal the openings at the two axial ends of the cylinder body (54).

Description

Technical Field

[0001] This specification discloses a silencer for air conditioning that is assembled in a vehicle air conditioning unit. Background Technology

[0002] To prevent refrigerant pulsation in vehicle air conditioning systems, a solution involving a muffler has been proposed. For example, Patent Document 1 discloses a structure in which a muffler is positioned near the compressor. In Patent Document 1, one end of the muffler is bolted to the compressor, and the other end is supported by a bracket.

[0003] However, while fluorinated refrigerants have historically been used for air conditioning, the use of other types of refrigerants has been explored in recent years. For example, some proposals have suggested utilizing carbon dioxide (hereinafter referred to as "CO2") as an air conditioning refrigerant. CO2 refrigerant has a lower warming potential compared to fluorinated refrigerants. On the other hand, CO2 refrigerant requires pressurization to a higher pressure than fluorinated refrigerants.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 6104256 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Patent Document 1's technology does not envision the use of high-pressure CO2 refrigerant, making it difficult to apply to air conditioning systems using CO2 refrigerant. In particular, since the CO2 refrigerant is pressurized to a high pressure, the silencer is also required to have high pressure resistance. The silencer disclosed in Patent Document 1 has room for improvement in this pressure resistance aspect.

[0009] Furthermore, in the past, mufflers were mostly formed through deep drawing, but deep drawing cannot increase the wall thickness. As a result, mufflers with high pressure resistance cannot be manufactured through deep drawing.

[0010] Therefore, this specification discloses a silencer for air conditioning that can use CO2 refrigerant.

[0011] Methods for solving problems

[0012] The silencer device for air conditioning disclosed in this specification is installed on the piping of an air conditioning refrigerant containing CO2. It is characterized by having a silencer body, which has: a cylindrical body without seams in the circumferential direction; and a pair of caps that are hermetically welded to the axial ends of the cylindrical body to seal the openings at both ends of the cylindrical body.

[0013] Because the muffler body is a welded structure, the wall thickness of the muffler body can be increased. Furthermore, this allows the muffler body to accept high-pressure CO2 refrigerant.

[0014] In this case, the wall thickness of the cylinder can also be greater than 4 mm.

[0015] By setting the wall thickness as described, it becomes possible to accept high-pressure CO2 refrigerant. Furthermore, it is generally accepted that the wall thickness limit is 3mm in the case of deep drawing. However, in the above-described structure, since the muffler body is formed by welding rather than deep drawing, a wall thickness of 4mm can be achieved.

[0016] In addition, the muffler body may further have a perforated separator, which is arranged in the internal space to divide the internal space of the cylinder in the axial direction and is formed with a plurality of through holes.

[0017] By designing the structure in question, pressure fluctuations in the refrigerant can be suppressed more effectively.

[0018] In addition, it may further include: an inlet pipe that guides the refrigerant to the muffler body; and an outlet pipe that guides the refrigerant from the muffler to the downstream side, wherein the inlet pipe and the outlet pipe are joined to the muffler body by brazing.

[0019] This reduces the manufacturing cost of the silencer. Specifically, the joint between the pipe and the silencer body experiences less pressure compared to the joint between the cylinder and the cover. By brazing the areas with lower pressure loads, manufacturing costs can be reduced.

[0020] In addition, the cylinder can also be a cylindrical shape with a fixed outer diameter.

[0021] By designing the structure in question, the cylinder can be manufactured using low-cost and simple manufacturing methods such as extrusion molding. As a result, the cost of the silencer can be reduced.

[0022] Invention Effects

[0023] According to the silencer for air conditioning disclosed in this specification, CO2 refrigerant can be used. Attached Figure Description

[0024] Figure 1 A diagram showing the structure of an air conditioning unit.

[0025] Figure 2 This is a 3D view of the area surrounding the silencing device.

[0026] Figure 3 This is a three-dimensional sectional view of the main body of the muffler.

[0027] Figure 4 This is an exploded cross-sectional view of the main body of other mufflers.

[0028] Figure 5 This is a cross-sectional view of the other muffler bodies. Detailed Implementation

[0029] The following description refers to the accompanying drawings to explain the silencer 50 used in a vehicle air conditioning system. Figure 1 This is a schematic diagram showing the structure of the air conditioning unit 10. The air conditioning unit 10 is mounted on a vehicle and regulates the temperature of the passenger compartment. Furthermore, the type of vehicle equipped with the air conditioning unit 10 is not particularly limited. Therefore, the vehicle can be either a motor-powered vehicle or an electric vehicle powered by an electric motor. Additionally, the vehicle can be a hybrid electric vehicle equipped with both an engine and an electric motor, a fuel cell vehicle equipped with a fuel cell, or a battery electric vehicle powered by electricity stored in a battery.

[0030] The air conditioning unit 10 has a refrigerant circuit 12. The refrigerant circuit 12 is a circuit that generates heat and latent heat by compressing, expanding, condensing, and evaporating the refrigerant during circulation. The heat generated in this refrigerant circuit 12 is used for heating, and the latent heat is used for cooling. Conventionally, fluorinated refrigerants have been commonly used. However, fluorinated refrigerants have a high environmental impact. Therefore, in this example, a CO2 refrigerant with CO2 as its main component is used. Compared to fluorinated refrigerants, CO2 refrigerants have a lower warming potential and a lower environmental impact. On the other hand, compared to fluorinated refrigerants, CO2 refrigerants require high pressure conditions for operation. For example, fluorinated refrigerants are used in a pressure range of 0.02 MPaG to 2 MPaG, while CO2 refrigerants are used in a pressure range of 0.8 MPaG to 10 MPaG. Therefore, equipment handling CO2 refrigerants requires high pressure resistance.

[0031] The refrigerant circuit 12 has a refrigerant piping 14 through which CO2 refrigerant flows. Midway along the path of this refrigerant piping 14, a compressor 16, a condenser 18, an energy storage tank 20, a refrigeration expansion valve 42, and an evaporator 22 are installed. The compressor 16 compresses the gaseous CO2 refrigerant. As described above, CO2 refrigerant requires higher pressure compared to fluorinated refrigerants. To meet this pressure requirement, a large-output, high-volume compressor 16 is selected.

[0032] The condenser 18 is a heat exchanger that allows CO2 refrigerant to exchange heat with external gas. During refrigeration operation, the condenser 18 functions as a condenser that condenses the gaseous CO2 refrigerant. A condenser fan 19 is located behind the condenser 18 for effectively drawing in external gas.

[0033] The energy storage unit 20 performs gas-liquid separation on the CO2 refrigerant and only sends the gaseous CO2 refrigerant to the compressor 16. Additionally, in Figure 1 In the example, the energy storage device 20 has a built-in heat exchanger.

[0034] The refrigeration expansion valve 42 is a solenoid valve that is throttled during refrigeration operation and completely closed during heating operation. When the refrigeration expansion valve 42 is throttled, the CO2 refrigerant is rapidly depressurized as it passes through it. The evaporator 22 is an evaporator that evaporates liquid CO2 refrigerant and is disposed within an air conditioning airflow channel provided in the unit housing 30. The latent heat generated during evaporation cools the air surrounding the evaporator 22.

[0035] In addition, although Figure 1 Although not illustrated, several solenoid valves are installed on the refrigerant circuit 12 to switch the flow direction of the air conditioning refrigerant. Furthermore, multiple PT (platinum thermometer) sensors 44 are configured on the refrigerant circuit 12 to detect the pressure and temperature of the CO2 refrigerant flowing in the refrigerant piping 14.

[0036] Inside the vehicle compartment, an air outlet mechanism 28 is installed. This mechanism cools or heats air drawn in from outside or inside the vehicle and blows it into the vehicle. The air outlet mechanism 28 includes a unit housing 30, a blower fan 32, and a heater core 33. An outlet (not shown) is formed at the lower end of the unit housing 30 to direct the air conditioning air into the vehicle. Furthermore, an evaporator 22 and a heater core 33 are installed inside the unit housing 30. During cooling operation, the evaporator 22 cools the air from the blower fan 32 using the latent heat of refrigerant vaporization. The cooled air conditioning air is then output into the vehicle, thereby cooling the interior.

[0037] During heating operation, the heater core 33 is heated by other heat sources. These other heat sources can be, for example, an engine or an electric heater. The heater core 33 is heated directly or indirectly via other heat sources, either directly or indirectly through a refrigerant such as water. A mode switching door 36 is located upstream of the heater core 33. The mode switching door 36 regulates the airflow through the heater core 33. During heating operation, the mode switching door 36 moves to a position that does not obstruct the airflow towards the heater core 33. Figure 1 (The position of the dotted line in the diagram). Thus, the air blown from the blower fan 32 passes through the heater core 33 and is heated. The heated air conditioning air is then output into the vehicle, thereby heating the passenger compartment.

[0038] In the air conditioning unit 10, a silencer 50 is further provided. The silencer 50 is positioned midway along the refrigerant piping 14 connecting the compressor 16 and the condenser 18. The silencer 50 suppresses the pulsation of the CO2 refrigerant, thereby suppressing noise caused by the pulsation. The silencer 50 includes a silencer body 52 that attenuates sound energy by expanding the gaseous CO2 refrigerant. Here, the pressure of the CO2 refrigerant increases downstream of the compressor 16. By arranging the silencer 50 downstream of the compressor 16, noise reduction can be achieved more effectively.

[0039] Since the operation of such an air conditioning unit 10 is known in the prior art, a detailed description is omitted here. Additionally, Figure 1 The structure of the air conditioning unit 10 shown is an example. Other structures can be modified as long as the air conditioning unit 10 has a compressor 16, a condenser 18, and a silencer 50. Therefore, for example, the air conditioning unit 10 may further include a battery cooling circuit for cooling electronic devices such as batteries or fuel cells.

[0040] As Figure 2 As shown, the silencer 50 (silencer body 52) is mounted on the condenser 18. Figure 2 as well as Figure 3 As shown, the muffler body 52 is a generally cylindrical cylindrical component. The muffler body 52 is fluidly connected to the compressor 16 and the condenser 18 via refrigerant piping 14.

[0041] The diameter of the muffler body 52 is sufficiently larger than the diameter of the refrigerant pipe 14. Therefore, CO2 refrigerant flows into the muffler body 52 through the refrigerant pipe 14, causing it to expand rapidly. This expansion attenuates the acoustic energy of the CO2 refrigerant and suppresses its pulsation.

[0042] As Figure 3As shown, the muffler body 52 is an elongated shape with an axial dimension greater than its diameter. For example, the axial dimension of the muffler body 52 is more than two or five times its diameter. The muffler body 52 is positioned in an upright posture, approximately parallel to the vertical direction of the vehicle, next to the condenser 18 in the vehicle width direction. By arranging the elongated muffler body 52 in such an upright posture, the muffler body 52 can be configured even in small gaps, thereby improving the vehicle's space efficiency.

[0043] The muffler body 52 has a cylindrical body 54 and a pair of covers 56. Both the cylindrical body 54 and the covers 56 are made of metal, such as stainless steel or carbon steel. Furthermore, the cylindrical body 54 is a seamless cylinder in the circumferential direction. The wall thickness t of the cylindrical body 54 is 4 mm or more, for example, 5 mm. Moreover, the outer diameter of the cylindrical body 54 is fixed. Therefore, the cylindrical body 54 can be manufactured using low-cost and simple manufacturing methods such as extrusion molding.

[0044] The cover 56 is a disc-shaped member that seals the opening at the axial end of the cylinder 54. Similar to the cylinder 54, the wall thickness t of the cover 56 is also 4 mm or more, for example, 5 mm. The cover 56 is hermetically welded to the axial end of the cylinder 54 by welding. For example, the joint between the cover 56 and the cylinder 54 is welded across the entire circumference, for example, by arc welding. Furthermore, welding is a well-known technique that joins materials by melting the base material itself at high temperatures.

[0045] Furthermore, a pipe hole is formed in the center of the cover 56, at which an inlet pipe 60 or an outlet pipe 62 is joined. The inlet pipe 60 guides CO2 refrigerant from the compressor 16 to the muffler body 52. ​​In this example, the inlet pipe 60 is joined to the upper cover 56. Similarly, the outlet pipe 62 guides CO2 refrigerant from the muffler body 52 to the condenser 18. In this example, the outlet pipe 62 is joined to the lower cover 56.

[0046] Both the inlet pipe 60 and the outlet pipe 62 are joined to the cover 56 by brazing. Brazing is a well-known technique whereby, after molten filler metal is poured into two base materials to be joined, the filler metal is allowed to solidify, thereby joining the two base materials. Because brazing does not melt the base materials, it can suppress deformation of the base materials compared to welding. Furthermore, compared to welding, brazing allows for the joining of two components at a lower cost.

[0047] The CO2 refrigerant, guided to the muffler body 52 via the inlet pipe 60, expands rapidly inside the muffler body 52. ​​This attenuates sound energy and reduces the pulsation of the CO2 refrigerant. The expanded CO2 refrigerant is then discharged to the condenser 18 via the outlet pipe 62.

[0048] Inside the cylinder 54, a perforated separator 58 is disposed. The perforated separator 58 is a circular plate with multiple holes formed therein. Furthermore, the diameter of the perforated separator 58 is approximately the same as the diameter of the cylinder 54. Therefore, the internal space of the cylinder 54 is divided axially by the perforated separator 58. During the passage of CO2 refrigerant through the perforated separator 58, the acoustic energy of the CO2 refrigerant is further attenuated. This more effectively prevents CO2 refrigerant pulsation. Additionally, the perforated separator 58 can also be joined to the cylinder 54 by welding or brazing.

[0049] However, conventional air conditioner muffler bodies are manufactured using a deep drawing process. Deep drawing is a stamping process that applies pressure to a metal sheet to create a cylindrical shape. This deep drawing process has the advantage of low cost. On the other hand, because the thin sheet deforms during deep drawing, it is impossible to obtain a cylindrical shape with a large wall thickness. Generally, in the case of deep drawing, although it depends on the raw material and shape, the wall thickness is limited to 3mm or less. Therefore, it is impossible to manufacture muffler bodies with high pressure resistance using deep drawing. Furthermore, as mentioned above, CO2 refrigerant is high-pressure, and when using CO2 refrigerant, the muffler body 52 is required to have high pressure resistance. Therefore, it is impossible to manufacture a muffler body 52 for CO2 refrigerant using deep drawing.

[0050] Therefore, as described above, the muffler body 52 of this example is constructed by welding a cover 56 onto the cylinder 54. By adopting the aforementioned structure, the wall thickness of the cylinder 54 and the cover 56 can be increased, and the pressure resistance of the muffler body 52 can be improved. Furthermore, a muffler body 52 capable of withstanding high-pressure CO2 refrigerant can be obtained.

[0051] Furthermore, as mentioned above, although the joint between the cylinder 54 and the cover 56 is welded together in this example, the joint between the cover 56 and the inlet pipe 60 or the outlet pipe 62 is brazed together. This is to reduce the manufacturing cost of the muffler body 52. ​​That is, typically, the joint between the cover 56 and the pipes 60, 62 experiences a smaller pressure load compared to the joint between the cylinder 54 and the cover 56. By brazing the parts with lower pressure loads, manufacturing costs can be reduced.

[0052] Furthermore, the structures described so far are merely examples; any structure described in technical solution 1 can be used, and other structures can be appropriately modified. For example, the inlet pipe 60 and outlet pipe 62 may not be joined to the cover 56, but rather to the circumferential surface of the cylinder 54. Additionally, pipes 60 and 62 may be joined to the cover 56 or cylinder 54 by welding, rather than brazing. Furthermore, the perforated separator 58 may be omitted. Moreover, inside the muffler body 52, the perforated separator 58 may be used instead, or other components may be further configured thereon.

[0053] Furthermore, the shape or structure of the cylinder 54 or the cover 56 can be appropriately modified. For example, the outer diameter of the cylinder 54 can also vary along the axial direction; for instance, the cylinder 54 can also be conical, barrel-shaped, stepped, etc. In addition, the cylinder 54 can also be divided into multiple parts along the axial direction. For example, as... Figure 4 As shown, the cylinder 54 can also be constructed by arranging the first cylinder 54a and the second cylinder 54b in the axial direction and welding them together. By joining multiple shorter cylinders 54a and 54b in this way to construct the cylinder 54, it is easier to install other components (such as the punched separator 58) inside the cylinder 54. Furthermore, the cylinder 54 is not limited to a circular cross-section, but can also be elliptical or square in cross-section.

[0054] Furthermore, the cover 56 is not limited to a flat plate; it can also be other shapes. For example, the cover 56 can also be as follows: Figure 5 As shown, it has a dome shape. By designing the structure in question, the pressure concentration at the joint between the cylinder 54 and the cover 56 can be mitigated. As a result, the pressure resistance of the silencer body 52 can be further improved.

[0055] Symbol Explanation

[0056] 10. Air conditioning unit; 12. Refrigerant circuit; 14. Refrigerant piping; 16. Compressor; 18. Condenser; 19. Condenser fan; 20. Energy storage unit; 22. Evaporator; 28. Air outlet mechanism; 30. Unit housing; 32. Blower fan; 33. Heater core; 36. Mode switching door; 42. Refrigeration expansion valve; 44. PT sensor; 50. Silencing device; 52. Silencing body; 54. Cylinder; 56. Cover; 58. Perforated separator; 60. Inlet pipe; 62. Outlet pipe.

Claims

1. A silencer for air conditioning, which is installed on a pipe containing an air conditioning refrigerant containing carbon dioxide, characterized in that, It has a muffler body, the muffler body having: The cylindrical body has no seams in the circumferential direction; A pair of caps are hermetically welded to the axial ends of the cylinder to seal the openings at both ends of the cylinder.

2. The silencer for air conditioning as described in claim 1, characterized in that, The wall thickness of the cylinder is greater than 4 mm.

3. The silencer for air conditioning as described in claim 1, characterized in that, The muffler body further includes a perforated separator, which is configured in the internal space to divide the internal space of the cylinder in the axial direction and is formed with a plurality of through holes.

4. The silencer for air conditioning as described in claim 1, characterized in that, Furthermore, it also possesses: An inlet pipe that directs the refrigerant to the muffler body; The outlet pipe guides the refrigerant from the muffler to the downstream side. The inlet pipe and the outlet pipe are joined to the muffler body by brazing.

5. The silencer for air conditioning as described in claim 1, characterized in that, The cylinder is a cylindrical shape with a fixed outer diameter.

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