Silencer for air conditioner

Abstract

To provide a silencer for air conditioning capable of using a CO2 refrigerant.SOLUTION: A muffler 50 for air conditioning provided in a pipe of an air conditioning refrigerant including a CO2 includes a muffler body 52 having a cylindrical body 54 having no joint in a circumferential direction, and a pair of lid bodies 56 airtightly welded to both axial ends of the cylindrical body 54 to close openings at both axial ends of the cylindrical body 54.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present specification discloses an air conditioner silencer that is incorporated into an on-vehicle air conditioner. [Background technology]

[0002] It has been proposed to provide a silencer in an automotive air conditioner to prevent pulsation of the air conditioning refrigerant. For example, Patent Document 1 discloses a structure in which a muffler is disposed near a compressor. In Patent Document 1, one end of the muffler is fixed to the compressor with a bolt, and the other end of the muffler is supported by a bracket.

[0003] While fluorine-based refrigerants have traditionally been used as air conditioning refrigerants, the use of other types of refrigerants has been considered in recent years. For example, some have proposed using carbon dioxide (hereinafter referred to as "CO2") as an air conditioning refrigerant. CO2 refrigerants have a lower global warming potential than fluorine-based refrigerants. On the other hand, CO2 refrigerants require higher pressures than fluorine-based refrigerants. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6104256 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology of Patent Document 1 was not designed to use high-pressure CO2 refrigerant, making it difficult to apply to air conditioners that use CO2 refrigerant. In particular, since CO2 refrigerant is pressurized to high pressure, the muffler also needs to have high pressure resistance. The muffler disclosed in Patent Document 1 has room for improvement in terms of pressure resistance.

[0006] Conventionally, mufflers have often been formed by drawing, but drawing does not allow for large wall thicknesses, making it impossible to manufacture mufflers with high pressure resistance.

[0007] Therefore, this specification discloses an air conditioner silencer that can use CO2 refrigerant. [Means for solving the problem]

[0008] The air conditioning silencer disclosed in this specification is an air conditioning silencer provided in a pipe for an air conditioning refrigerant containing CO2, and is characterized by comprising a muffler body having a cylindrical body having no joints in the circumferential direction, and a pair of lid bodies airtightly welded to both ends of the cylindrical body in the axial direction to close openings at both ends of the axial direction of the cylindrical body.

[0009] The muffler body has a welded structure, which allows the wall thickness of the muffler body to be increased, allowing the muffler body to receive high-pressure CO2 refrigerant.

[0010] In this case, the wall thickness of the cylindrical body may be greater than 4 mm.

[0011] This thickness allows the muffler to accept high-pressure CO2 refrigerant. Generally, the maximum thickness achieved by drawing is said to be 3 mm. However, with the above-mentioned configuration, the muffler body is formed by welding, not by drawing, making a thickness of 4 mm possible.

[0012] The muffler body may further include a punching separator having a plurality of through holes formed therein, the punching separator being arranged in the internal space of the cylindrical body to divide the internal space in the axial direction.

[0013] With this configuration, pulsation of the pressure of the refrigerant can be more effectively suppressed.

[0014] The muffler may further include an inlet pipe that guides the refrigerant to the muffler body and an outlet pipe that guides the refrigerant downstream from the muffler, and the inlet pipe and the outlet pipe may be joined to the muffler body by brazing.

[0015] This reduces the manufacturing cost of the silencer. That is, the joint between the pipe and the muffler body is subjected to a smaller pressure load than the joint between the cylindrical body and the lid. By brazing the area where the pressure load is smaller, the manufacturing cost can be reduced.

[0016] The cylindrical body may also be a cylindrical body having a constant outer diameter.

[0017] With this configuration, the cylindrical body can be manufactured by a low-cost, simple method such as extrusion molding, which results in a reduction in the cost of the silencer. [Effects of the Invention]

[0018] The silencer for air conditioning disclosed in this specification makes it possible to use CO2 refrigerant. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an air conditioning device. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 10 is an exploded cross-sectional view of another muffler body. [Figure 5] FIG. 10 is a cross-sectional view of another muffler body. DETAILED DESCRIPTION OF THE INVENTION

[0020] A silencer 50 for an in-vehicle air conditioner will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of an air conditioner 10. The air conditioner 10 is mounted on a vehicle and adjusts the temperature in the vehicle compartment. The type of vehicle on which the air conditioner 10 is mounted is not particularly limited. Therefore, the vehicle may be an engine vehicle powered by an engine, or an electric vehicle powered by a motor. The vehicle may also be a hybrid electric vehicle equipped with both an engine and a motor, a fuel cell vehicle equipped with a fuel cell, or a battery electric vehicle that runs on electricity stored in a battery.

[0021] The air conditioner 10 includes a refrigerant circuit 12. The refrigerant circuit 12 generates heat and latent heat by compressing, expanding, condensing, and evaporating the refrigerant as it circulates. The heat generated in the refrigerant circuit 12 is used for heating, and the latent heat is used for cooling. Conventionally, fluorinated refrigerants have been widely used as refrigerants. However, fluorinated refrigerants have a problem with their environmental impact. Therefore, this example employs a CO2 refrigerant, which is primarily composed of CO2. CO2 refrigerant has a lower global warming potential and a lower environmental impact than fluorinated refrigerants. However, CO2 refrigerant must be used under higher pressures than fluorinated refrigerants. For example, fluorinated refrigerants are used in a pressure range of 0.02 MPaG to 2 MPaG, while CO2 refrigerant is used in a pressure range of 0.8 MPaG to 10 MPaG. Therefore, equipment that handles CO2 refrigerants must have high pressure resistance.

[0022] The refrigerant circuit 12 has a refrigerant pipe 14 through which a CO2 refrigerant flows. Along the route of this refrigerant pipe 14, a compressor 16, a condenser 18, an accumulator 20, a cooling expansion valve 42, and an evaporator 22 are provided. The compressor 16 compresses the gaseous CO2 refrigerant. As mentioned above, CO2 refrigerant needs to be pressurized to a higher pressure than fluorinated refrigerants. To meet this pressure requirement, a large, high-output compressor 16 is selected.

[0023] Condenser 18 is a heat exchanger that exchanges heat between the CO2 refrigerant and outside air. During cooling operation, condenser 18 functions as a condenser that condenses the gaseous CO2 refrigerant. A condenser fan 19 is located behind condenser 18 to efficiently draw in outside air.

[0024] The accumulator 20 separates the CO2 refrigerant into gas and liquid, and sends only the gaseous CO2 refrigerant to the compressor 16. In the example of Fig. 1, the accumulator 20 has a built-in heat exchanger.

[0025] The cooling expansion valve 42 is a solenoid valve that is throttled during cooling operation and completely closed during heating operation. When the cooling expansion valve 42 is throttled, the CO2 refrigerant is rapidly depressurized as it passes through the cooling expansion valve 42. The evaporator 22 evaporates the liquid CO2 refrigerant and is disposed in the air conditioning airflow path provided in the unit case 30. The air around the evaporator 22 is cooled by the latent heat generated during this evaporation.

[0026] 1, the refrigerant circuit 12 is provided with several solenoid valves that switch the flow direction of the air-conditioning refrigerant. Furthermore, the refrigerant circuit 12 is provided with multiple PT sensors 44 for detecting the pressure and temperature of the CO2 refrigerant flowing through the refrigerant pipe 14.

[0027] A blower mechanism 28 is disposed within the vehicle cabin. The blower mechanism 28 cools or heats air taken in from outside or inside the vehicle and blows the air into the vehicle interior. The blower mechanism 28 has a unit case 30, a blower fan 32, and a heater core 33. An air outlet (not shown) is formed at the downstream end of the unit case 30 for directing conditioned air into the vehicle interior. The evaporator 22 and the heater core 33 are also disposed within the unit case 30. During cooling operation, the evaporator 22 cools the air sent from the blower fan 32 by using latent heat generated when the air-conditioning refrigerant evaporates. The cooled conditioned air is output into the vehicle interior to cool the vehicle interior.

[0028] During heating operation, the heater core 33 is heated by another heat source. The other heat source may be, for example, an engine or an electric heater. The heater core 33 is heated directly by the other heat source or indirectly via a refrigerant such as water. A mode switching door 36 is disposed upstream of the heater core 33. The mode switching door 36 adjusts the amount of air passing through the heater core 33. During heating operation, the mode switching door 36 moves to a position (the position indicated by the dashed line in FIG. 1 ) that does not block the air flow toward the heater core 33. This allows the air sent from the blower fan 32 to pass through the heater core 33 and be heated. The heated air-conditioned air is output into the vehicle interior, heating the vehicle cabin.

[0029] The air conditioner 10 is further provided with a silencer 50. The silencer 50 is disposed midway along the refrigerant pipe 14 connecting the compressor 16 and the condenser 18. The silencer 50 suppresses the pulsation of the CO2 refrigerant and, ultimately, the noise caused by the pulsation. The silencer 50 includes a muffler 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. Placing the silencer 50 downstream of the compressor 16 enables more efficient noise reduction.

[0030] The operation of the air conditioner 10 is conventionally known, and therefore a detailed description thereof will be omitted here. The configuration of the air conditioner 10 shown in Fig. 1 is one example. As long as the air conditioner 10 has the compressor 16, the condenser 18, and the silencer 50, other configurations may be changed. Therefore, for example, the air conditioner 10 may further have a battery cooling circuit that cools electronic devices such as a battery or a fuel cell.

[0031] 2, the silencer 50 (muffler body 52) is attached to the condenser 18. The muffler body 52 is a substantially cylindrical member as shown in FIGS. 2 and 3. The muffler body 52 is fluidly connected to the compressor 16 and the condenser 18 via the refrigerant piping 14.

[0032] The diameter of the muffler body 52 is sufficiently larger than the diameter of the refrigerant pipe 14. Therefore, the CO2 refrigerant expands rapidly when it flows from the refrigerant pipe 14 into the muffler body 52. ​​This expansion attenuates the sound energy of the CO2 refrigerant and suppresses the pulsation of the CO2 refrigerant.

[0033] As shown in Figure 3, the muffler body 52 has an elongated shape with an axial dimension greater than its diameter. For example, the axial dimension of the muffler body 52 is at least two times or at least five times the diameter. The muffler body 52 is arranged in an upright position with its axial direction 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 an upright position in this way, the muffler body 52 can be arranged in small gaps, improving the space efficiency of the vehicle.

[0034] The muffler body 52 has a cylindrical body 54 and a pair of lids 56. The body 54 and the lids 56 are both made of metal, such as stainless steel or carbon steel. The body 54 is cylindrical and has no seams in the circumferential direction. The wall thickness t of the body 54 is 4 mm or more, for example, 5 mm. The body 54 has a constant outer diameter. Therefore, the body 54 can be manufactured using a simple, low-cost manufacturing method, such as extrusion molding.

[0035] The lid 56 is a disk-shaped member that closes the opening at the axial end of the cylindrical body 54. The thickness t of the lid 56 is 4 mm or more, for example, 5 mm, similar to that of the cylindrical body 54. The lid 56 is hermetically welded to the axial end of the cylindrical body 54. For example, the joint between the lid 56 and the cylindrical body 54 is welded, for example, by arc welding, around the entire circumference. As is well known, welding is a technique in which the base material itself is melted at high temperature to join the materials.

[0036] A pipe hole is formed in the center of the lid 56, and an inlet pipe 60 or an outlet pipe 62 is joined to the pipe hole. The inlet pipe 60 is a pipe that guides the CO2 refrigerant from the compressor 16 to the muffler body 52. ​​In this example, the inlet pipe 60 is joined to the upper lid 56. The outlet pipe 62 is a pipe that guides the CO2 refrigerant from the muffler body 52 to the condenser 18. In this example, the outlet pipe 62 is joined to the lower lid 56.

[0037] Both the inlet pipe 60 and the outlet pipe 62 are joined to the lid 56 by brazing. As is well known, brazing is a technique for joining two base materials to be joined by dropping molten solder between them and then solidifying the solder. Because brazing does not melt the base materials, it can suppress deformation of the base materials compared to welding. Furthermore, brazing can join two members at a lower cost compared to welding.

[0038] The CO2 refrigerant introduced into the muffler body 52 via the inlet pipe 60 rapidly expands within the muffler body 52. ​​This attenuates sound energy and reduces pulsation of the CO2 refrigerant. The expanded CO2 refrigerant is output to the condenser 18 via the outlet pipe 62.

[0039] A punched separator 58 is disposed inside the cylindrical body 54. The punched separator 58 is a circular plate with a plurality of holes formed therein. The diameter of the punched separator 58 is approximately the same as the diameter of the cylindrical body 54. Therefore, the internal space of the cylindrical body 54 is divided in the axial direction by the punched separator 58. As the CO2 refrigerant passes through the punched separator 58, the sound energy of the CO2 refrigerant is further attenuated. This more effectively prevents pulsation of the CO2 refrigerant. The punched separator 58 may be joined to the cylindrical body 54 by welding or brazing.

[0040] Conventional muffler bodies for air conditioners have been manufactured by drawing. Drawing is a type of press work in which pressure is applied to a metal plate to produce a cylindrical shape. This drawing process has the advantage of being low cost. However, because drawing deforms a thin plate, it is not possible to obtain a thick cylindrical shape. Generally, drawing limits the wall thickness to 3 mm or less, depending on the material and shape. Therefore, drawing has not been able to manufacture a muffler body with high pressure resistance. On the other hand, as mentioned above, CO2 refrigerant is a high-pressure refrigerant, and when using CO2 refrigerant, the muffler body 52 must have high pressure resistance. Therefore, drawing cannot be used to manufacture a muffler body 52 for a CO2 refrigerant.

[0041] Therefore, as described above, the muffler body 52 of this example is constructed by welding the lid body 56 to the cylindrical body 54. With this construction, the thickness of the cylindrical body 54 and the lid body 56 can be increased, and the pressure resistance of the muffler body 52 can be improved. This results in a muffler body 52 that can receive high-pressure CO2 refrigerant.

[0042] As described above, in this example, the joint between the cylindrical body 54 and the lid body 56 is welded, but the joint between the lid body 56 and the inlet pipe 60 or the outlet pipe 62 is brazed. This is to reduce the manufacturing cost of the muffler body 52. ​​That is, the joint between the lid body 56 and the pipes 60, 62 usually experiences a smaller pressure load than the joint between the cylindrical body 54 and the lid body 56. By brazing the portion that experiences a smaller pressure load, the manufacturing cost can be reduced.

[0043] Furthermore, the configurations described so far are all examples, and other configurations may be changed as appropriate as long as the configuration of claim 1 is included. For example, the inlet pipe 60 and the outlet pipe 62 may be joined to the circumferential surface of the cylindrical body 54 rather than to the lid body 56. Furthermore, the pipes 60, 62 may be joined to the lid body 56 or the cylindrical body 54 by welding rather than brazing. Furthermore, the punched separator 58 may be omitted. Furthermore, another member may be disposed inside the muffler body 52 instead of or in addition to the punched separator 58.

[0044] Furthermore, the shapes and configurations of the cylindrical body 54 and the lid 56 may be modified as appropriate. For example, the outer diameter of the cylindrical body 54 may vary along the axial direction. For example, the cylindrical body 54 may be cone-shaped, barrel-shaped, or stepped. The cylindrical body 54 may also be divided into multiple pieces in the axial direction. For example, as shown in FIG. 4, the cylindrical body 54 may be formed by welding a first cylindrical body 54a and a second cylindrical body 54b arranged in the axial direction. By forming the cylindrical body 54 by joining multiple short cylindrical bodies 54a and 54b in this manner, the work of attaching other members (e.g., a punched separator 58) inside the cylindrical body 54 can be simplified. Furthermore, the cross section of the cylindrical body 54 is not limited to a circular shape, and it may also be an elliptical or rectangular cross section.

[0045] Furthermore, the cover 56 is not limited to a flat plate, and may have other shapes. For example, the cover 56 may be dome-shaped, as shown in FIG. 5. This configuration can reduce the concentration of pressure at the joint between the cylindrical body 54 and the cover 56. As a result, the pressure resistance of the muffler body 52 can be further improved. [Explanation of symbols]

[0046] 10 air conditioning unit, 12 refrigerant circuit, 14 refrigerant piping, 16 compressor, 18 condenser, 19 condenser fan, 20 accumulator, 22 evaporator, 28 blowing mechanism, 30 unit case, 32 blower fan, 33 heater core, 36 mode switching door, 42 cooling expansion valve, 44 PT sensor, 50 silencer, 52 muffler body, 54 cylinder, 56 lid, 58 punching separator, 60 inlet pipe, 62 outlet pipe.

Claims

1. An air conditioning silencer provided in a pipe for an air conditioning refrigerant containing CO2, a cylindrical body having no joints in the circumferential direction; a pair of lids hermetically welded to both ends of the cylindrical body in the axial direction to close openings at both ends of the cylindrical body; A silencer for an air conditioner, comprising a muffler body having a

2. The silencer for an air conditioner according to claim 1, The silencer for an air conditioner, wherein the cylindrical body has a wall thickness of greater than 4 mm.

3. The silencer for an air conditioner according to claim 1, The muffler body further includes a punching separator having a plurality of through holes formed therein, the punching separator being arranged in the internal space of the cylindrical body so as to divide the internal space in the axial direction.

4. The silencer for an air conditioner according to claim 1, further comprising: an inlet pipe that guides the refrigerant to the muffler body; an outlet pipe that guides the refrigerant downstream from the muffler; Equipped with The inlet pipe and the outlet pipe are joined to the muffler body by brazing. A silencer for air conditioning.

5. The silencer for an air conditioner according to claim 1, The silencer for an air conditioner, wherein the cylindrical body has a cylindrical shape with a constant outer diameter.

Images