KR20170113327A - Air conditioner - Google Patents

Abstract

The air conditioner of the present invention comprises a compressor connected to the compressor at one end and to the refrigeration cycle component at the other end to form a single pipe between the compressor and the refrigeration cycle component, And at least a portion of the stainless steel pipe is machined and formed integrally with the remainder of the stainless steel pipe.

Description

AIR CONDITIONER

The present invention relates to an air conditioner having a pipe for attenuating vibrations generated in a refrigeration cycle.

The air conditioner refers to a device that cools or heats the room using a refrigeration cycle. The refrigeration cycle includes a compressor, a condenser, an expansion device, and an evaporator, wherein the compressor, the condenser, the expansion device, and the evaporator are sequentially connected by piping. The refrigerant circulates through the pipe, the compressor, the condenser, the expansion device, and the evaporator.

A flow path is formed in the condenser and the evaporator during the refrigeration cycle. The refrigerant passes through the flow path formed in the condenser and the evaporator, and is heat-exchanged with the surroundings to condense or evaporate. The condenser and the evaporator operate as a heat exchanger. The flow path is for the flow of the refrigerant and the refrigerant flows into the flow path, so that the concept is included in the pipe in a broad sense.

In this way, the piping not only connects the components of the refrigeration cycle to each other, but also serves as a passage for the compressor and the condenser. Conventional piping is mainly made of copper (Cu, copper, copper). However, there are some problems with piping made of copper.

First, copper has limited reliability due to the occurrence of corrosion. In the case of a chiller heat pipe, a custom pipe or a replacement is made to remove the internal scale and the like.

Next, copper does not have high pressure resistance characteristics enough to be used as a high-pressure new refrigerant flow path such as R32. If the piping made of copper is used as a high-pressure new-coolant channel, it can not withstand high pressure over time and is liable to be damaged.

A stainless steel pipe has been proposed in Japanese Patent Application Laid-Open No. 2003-0074232 for compensating for the disadvantages of such a copper pipe. Stainless steel pipe is made of stainless steel material. Stainless steel material generally has stronger corrosion resistance than copper material. Therefore, the stainless steel pipe can solve the problem of the copper pipe that the corrosion occurs. In addition, stainless steel material has sufficient high pressure resistance characteristics, so there is less risk of breakage even at high pressure.

However, the conventional stainless steel material including the stainless steel pipe disclosed in JP-A-2003-0074232 has too high strength and high hardness properties compared with the copper material, so that there is a problem of workability which was not present in the copper pipe.

The piping used in the air conditioner is formed not only in a straight shape but also in a curved shape due to space limitation, and some of the piping is formed in a straight shape and the other part is formed in a curved shape. A straight pipe refers to a pipe extending in one direction along a straight line, and a curved pipe means a pipe bent along a curve.

However, since conventional stainless steel materials have excessively high strength and high hardness properties compared to copper materials, it is difficult to manufacture curved piping from stainless steel (see FIG. 1). For example, even if a linear pipe made of stainless steel material is mechanically pressed and formed into a curved pipe, there is a problem in that it is not completely plastic deformed but partially elastically deformed so that sufficient processing can not be performed.

In particular, stainless steel materials are known to inherently have high strength and high hardness properties. Therefore, it is recognized that the processability of the stainless steel material is difficult to be improved by using the stainless steel material.

Furthermore, since more than 10% of the material cost of the entire air conditioner product is occupied by the piping, the performance improvement and the cost reduction demand for the piping are continuously increasing.

On the other hand, the compressor is configured to compress the refrigerant. In the process of compressing the refrigerant, the compressor generates vibration. The vibration generated in the compressor is transmitted to the other refrigeration cycle components through the piping, thereby causing noise and causing deterioration of the durability of the air conditioner from a long-term perspective. Also, vibration and noise cause the pressure drop of the refrigerant passing through the piping, which causes the efficiency of the refrigeration cycle to deteriorate.

Conventionally, in order to solve such a problem, a flexible pipe is applied. A flexible pipe refers to a pipe having an outer circumferential surface surrounded by a wire braid.

When a flexible pipe is applied to a refrigeration cycle, a vibration damping effect can be obtained to some extent. However, the flexible pipe has a disadvantage that it does not have sufficient durability due to local stresses. In addition, the flexible pipe has a problem that a pressure drop occurs in the refrigerant passing through the pipe, resulting in a reduction in the efficiency of the refrigeration cycle.

Therefore, it is required to introduce a new pipe to solve the above-mentioned problem.

A first object of the present invention is to provide a stainless steel material with a new constitution which can solve the problems of corrosion resistance and pressure resistance characteristics of a copper material and solve the problem of high strength and high hardness of a conventional stainless steel material will be.

A second object of the present invention is to provide a pipe capable of securing sufficient workability through a new stainless steel material having ductility as compared with a conventional stainless steel material.

A third object of the present invention is to propose a piping made of a stainless steel material and a system having the piping.

A fourth object of the present invention is to provide a stainless steel pipe having a structure capable of attenuating vibrations generated in a process of compressing a refrigerant in a compressor from being transmitted to other refrigeration cycle components while riding on a pipe, and an air conditioner having the stainless steel pipe will be.

A fifth object of the present invention is to provide a stainless steel pipe having a corrugated portion integrally formed with a pipe without a joint to mitigate stress concentration generated in the joint and an air conditioner having the stainless steel pipe.

A sixth object of the present invention is to propose a stainless steel pipe having a structure capable of relieving a pressure drop phenomenon generated in a refrigerant passing through a pipe and an air conditioner having the stainless steel pipe.

A seventh object of the present invention is to propose a wrinkle structure which can be easily bend even with a relatively small force, and to propose a size of a wrinkle portion capable of relieving stress concentration and suppressing a pressure drop of a refrigerant.

The eighth object of the present invention is to propose a stainless steel pipe which can simplify the piping structure of the air conditioner.

In order to accomplish one object of the present invention, a stainless steel according to an embodiment of the present invention is defined as a composition, a base texture, and an average particle size.

The composition of the stainless steel is as follows: C: 0.03% or less, Si: more than 0%, 1.7% or less, Mn: 1.5 to 3.5%, Cr: 15.0 to 18.0%, Ni: 7.0 to 9.0% : 0.03% or less, P: 0.04% or less, S: 0.04% or less, N: 0.03% or less, the balance being Fe and unavoidable impurities.

The base structure of stainless steel is made of austenite. The base structure of stainless steel is most preferably made of only austenite. The base structure of stainless steel can be composed of austenite and delta ferrite. In this case, the austenite should occupy most of the base structure based on the grain size area. Stainless steel may have an austenitic matrix structure of 99% or more based on the grain size area, and may have a delta ferrite matrix structure of 1% or less.

Stainless steel has an average diameter of 30 to 60 탆. This particle number corresponds to the American Society for Testing and Materials (ASTM) Grain size No. 5.0 to 7.0.

Also, the pipe made of stainless steel, that is, the stainless steel pipe is made of the above-described stainless steel, and the stainless steel is defined as composition, base structure and average particle size as before.

Further, the air conditioner according to an embodiment of the present invention includes a stainless steel pipe having a corrugated portion. In particular, at least a part of the corrugated portion of the stainless steel pipe is processed and formed integrally with the remaining portion of the stainless steel pipe.

Stainless steel piping forms a single pipe between the compressor and the refrigeration cycle components. For example, one end of the stainless steel pipe is connected to the compressor and the other end is connected to the refrigeration cycle component. Here, the compressor means all the configurations for compressing the refrigerant, and the refrigerating cycle components are connected to the compressor by the stainless steel piping.

The refrigeration cycle component means a device installed on at least one of the upstream side and the downstream side of the compressor to supply the refrigerant to the compressor or receive the refrigerant from the compressor. The refrigerating cycle component and the compressor form part of the refrigeration cycle.

According to an embodiment of the present invention, the pleats are thinner than the region without the pleats by more than 0 to 5%.

According to another embodiment of the present invention, the corrugated portion is formed by repeatedly alternating the mountains and the valleys, and the thickness (T1) of the stainless steel pipe, the thickness (T2) of the stainless steel pipe, The thickness (T3) of the stainless steel pipe between the corrugations has a difference of more than 0 and 2% or less.

According to another embodiment of the present invention, the corrugations are formed by repeatedly alternating the mountains and the valleys, and the mountains are formed by 2 to 5 per 1 cm length along the longitudinal direction of the stainless steel pipe.

According to another example of the present invention, the distance between two adjacent mountains may be 8 mm or less.

According to another embodiment of the present invention, the stainless steel pipe has a curved region formed by bending at least a part of the area.

The pleats may be formed in the curved region.

The stainless steel pipe may have a linear region, and the corrugation may be formed over the straight region and the curved region.

According to another embodiment of the present invention, the ridges of the wrinkles are formed to be spaced apart from each other, and the ribs are also spaced apart from each other.

According to another example of the present invention, the acid of the corrugation protrudes in a circular shape along a direction orthogonal to the outer circumferential surface of the stainless steel pipe.

According to another example of the present invention, the difference in the distance between the outer diameter at the mountain and the outer diameter at the valley is 2.8 to 3.2 mm.

According to another embodiment of the present invention, the outer diameter of the valley has an outer diameter in a region without a wrinkle portion and a thickness difference of more than 0 and 2% or less, and an inner diameter of the valley is an inner diameter in a region without a wrinkle portion, And a thickness difference of not more than 2%.

According to another example of the present invention, the stainless steel pipe has a copper bonding portion at at least one end, and the copper bonding portion is made of copper having the shape of a straight pipe, and is bonded to the outer circumferential face or the inner circumferential face of the end portion.

The stainless steel of the present invention can have lower strength and lower hardness properties than conventional stainless steel through a composition containing copper (Cu), a matrix structure of austenite, and an average particle size of 30 to 60 탆. In conventional stainless steels, the problem of workability has been raised due to the high strength and high hardness of the steel, which is excessively higher than that of copper, and it has become a cause of manufacturing a tube bent with stainless steel.

However, since the stainless steel of the present invention has a strength and hardness of copper level, sufficient workability can be ensured and it can be utilized in the production of pipes (straight pipe or bent pipe) necessary for a system such as an air conditioner. Particularly, in the case of manufacturing a tube bent with stainless steel of the present invention, the conventional problem that plastic deformation is not sufficiently achieved can be solved.

In addition, when the piping is manufactured using the stainless steel of the present invention, the heat loss reduction effect and the corrosion resistance performance can be secured. The reduction of heat loss and corrosion resistance are intrinsic characteristics of the stainless steel material, and the stainless steel of the present invention does not lose the inherent properties of stainless steel even though it has lower strength and lower hardness than conventional stainless steel.

The piping made of the stainless steel material of the present invention may have a limit pressure and a limit bending moment similar to those of the copper piping even if the piping is made thinner than the copper piping. Therefore, it is possible to design an optimal stainless steel pipe through the minimum thickness of the stainless steel pipe proposed in the present invention.

Further, since the stainless steel pipe has the corrugated portion, the transmission of vibration generated in the process of compressing the refrigerant in the compressor can be attenuated.

Particularly, since the corrugated portion is formed integrally with the rest of the stainless steel pipe, it is possible to realize a structure without a joint, and the problem of stress concentration occurring in the joint portion can be solved fundamentally. Furthermore, since the corrugation is formed integrally with the remainder of the stainless steel pipe, the corrugation can be formed at any position of the stainless steel pipe.

Further, the present invention has a substantially constant thickness at all portions of the stainless steel pipe including the corrugated portion. Therefore, the stainless steel pipe of the present invention can secure sufficient strength even without a wire braid, and can solve the problem of pressure drop, vibration, and noise of a refrigerant, which may be caused by unevenness in thickness.

Also, since the wrinkles have a very dense structure of mountains and valleys, the inner circumferential surface can be made close to the smooth surface. Therefore, the stainless steel pipe of the present invention can solve the problem of the pressure drop, vibration, and noise of the refrigerant, which may occur due to the rough and uneven inner circumferential surface.

Since the ridges of the wrinkles are formed to be spaced apart from each other and the ribs are also spaced apart from each other, the wrinkles do not interfere with the warping of the stainless steel pipe. The stainless steel pipe of the present invention can be easily bent even with a relatively small force, as opposed to the difficulty of bending the pipe due to the corrugated portion of the spiral structure in the pipe having the corrugated portion of the helical structure.

The use of the stainless steel pipe of the present invention in which the corrugated part is integrally formed in the pipe allows suppressing the transmission of vibration and noise even in a small number of curved areas, thereby simplifying the piping structure of the air conditioner.

Fig. 1 is a graph of stress-strain versus physical properties of stainless steel and copper.
2A is a microstructure photograph showing a stainless steel according to Example 1 of the present invention.
FIG. 2B is a microstructure photograph showing the stainless steel according to the second embodiment of the present invention. FIG.
3 to 6 are photographs of microstructures showing stainless steels according to Comparative Examples 2 to 5, respectively.
7 is a stress-strain graph in which physical properties of the stainless steel of Example 3 were evaluated.
8 is a block diagram showing a refrigeration cycle of an air conditioner according to an embodiment of the present invention.
9 is a partial view showing the air conditioner of the present invention.
10 is a cross-sectional view partially showing a corrugated portion of the stainless steel pipe shown in Fig.
11A is a conceptual view showing a state in which two components of a refrigeration cycle are connected by a conventional piping having no corrugated portion.
FIG. 11B is a view showing a state where two components of a refrigeration cycle are connected to a stainless steel pipe of the present invention having a corrugated portion.
12 is a conceptual view showing a stainless steel pipe according to another embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings. In the present specification, the same reference numerals are given to the same components in different embodiments, and the description thereof is replaced with the first explanation. As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

The stainless steel of the present invention exhibits lower strength and lower hardness than conventional stainless steels. The stainless steel of the present invention has strength and hardness at the copper material level. The low strength and low hardness characteristics of the stainless steel can be determined by comparing the yield strength, tensile strength, hardness and elongation of the stainless steel material of the present invention with those of the copper material. If stainless steel has properties of strength and hardness at the copper material level, the problem of workability, which was a problem in conventional stainless steel, can be solved.

The low strength and low hardness properties of stainless steel are determined by the composition of the stainless steel, the texture of the matrix and the average grain size. Hereinafter, each item for determining the low strength and low hardness characteristics of the stainless steel will be described. Unless otherwise indicated, the respective contents are weight percent (wt.%).

1. Composition of Stainless Steel

(1) Carbon (C): Not more than 0.03%

The stainless steel of the present invention includes carbon (C) and chromium (Cr). Carbon reacts with chromium to precipitate into chromium carbide, which causes depletion of chromium at or near the grain boundary, causing corrosion. Therefore, it is desirable that the content of carbon is kept small. When the content of carbon is more than 0.03%, it is difficult for the stainless steel to have the strength and hardness at the copper material level, and it is difficult to secure sufficient workability by utilizing the characteristics of low strength and low hardness. Therefore, in the present invention, the content of carbon is set to 0.03% or less so that the stainless steel has a low strength and a low hardness at the copper material level, thereby ensuring sufficient workability.

(2) Silicon (Si, silicon): more than 0 and less than 1.7%

Austenite has a lower yield strength than ferrite or martensite. Therefore, in order for the stainless steel of the present invention to have low strength and low hardness properties at the copper material level, the base structure of the stainless steel should be made of austenite.

However, silicon is a source of ferrite. As the content of silicon increases, the proportion of ferrite in the matrix increases and the stability of ferrite increases. Therefore, it is preferable that the content of silicon is kept small. If the content of silicon exceeds 1.7%, it is difficult for stainless steel to have strength and hardness at the copper material level, and it is difficult to secure sufficient workability. Therefore, in the present invention, the content of silicon is set to 1.7% or less so that the stainless steel has a low strength and a low hardness at the level of the copper material and sufficient workability is secured through the low strength and low hardness.

(3) Manganese (Mn, Manganess): 1.5 to 3.5%

Manganese is a necessary element to inhibit the transformation of the base structure of stainless steel into martensite. If the content of manganese is less than 1.5%, the effect of suppressing the phase transformation by manganese is not sufficiently exhibited. Therefore, in the present invention, the lower limit of manganese is set to 1.5% in order to sufficiently obtain the effect of inhibiting the phase transformation by manganese.

However, as the content of manganese increases, the yield strength of the stainless steel rises, so that the stainless steel can not have a low strength characteristic at the copper level. Therefore, in the present invention, the upper limit of manganese is set to 3.5% so that the stainless steel can have a low strength property.

(4) Chromium (Cr, Chromium): 15.0 to 18.0%

Chromium is a contributing factor to the corrosion resistance of stainless steels. Corrosion initiation refers to the first occurrence of corrosion in the absence of corrosion in an un-corroded base material, and resistance to corrosion initiation refers to the property of inhibiting the first occurrence of corrosion on the base material. If the content of chromium is lower than 15.0%, stainless steel does not have sufficient resistance against corrosion initiation. Therefore, in the present invention, the lower limit of chromium is set to 15.0%, so that stainless steel has sufficient corrosion resistance.

However, if the amount of chromium becomes too large, the strength of the stainless steel increases, and on the contrary, the elongation decreases. If the content of chromium exceeds 18.0%, the increase in the strength and the decrease in the elongation percentage of the stainless steel become large, and it becomes difficult to secure sufficient workability of the stainless steel. Therefore, in the present invention, the upper limit of chromium is set to 18.0%, so that stainless steel can secure sufficient workability.

Furthermore, since chromium is an expensive element, the content of chromium also affects the economics of stainless steel. Therefore, the content of chromium is set in the above-mentioned range to ensure the economical efficiency of stainless steel.

(5) Nickel (Nickel): 7.0 to 9.0%

Nickel is the element that improves the corrosion growth resistance of stainless steel. Corrosion growth means that the corrosion that has already occurred in the base material spreads over a wide range, and the corrosion growth resistance means a property of inhibiting the growth of corrosion. Corrosion growth resistance is conceptually different from corrosion resistance. When the content of nickel is less than 7.0%, stainless steel does not have sufficient corrosion growth resistance. Therefore, in the present invention, the lower limit of nickel is set to 7.0% so that stainless steel can have sufficient corrosion growth resistance.

However, if too much nickel is added, the strength and hardness of the stainless steel will increase. If the content of nickel exceeds 9.0%, the strength and hardness increase of the stainless steel become large, and it becomes difficult to secure sufficient workability of the stainless steel. Therefore, in the present invention, the upper limit of nickel is set to 9.0% so that sufficient workability can be ensured in stainless steel.

Furthermore, because nickel is an expensive element, the content of nickel also affects the economics of stainless steel. Therefore, the content of nickel is set within the above-mentioned range to ensure the economical efficiency of stainless steel.

(6) Copper (Cu, Copper): 1.0 to 4.0%

Copper is a necessary element to inhibit the transformation of the base structure of stainless steel into martensite. If the content of copper is less than 1.0%, the effect of suppressing the phase transformation by copper is not sufficiently exhibited. Therefore, in the present invention, the lower limit of copper is set to 1.0% in order to sufficiently obtain the effect of suppressing the phase transformation by copper. In particular, in order for the stainless steel of the present invention to have low strength and low hardness properties at the copper level, the content of copper must be strictly controlled to at least 1.0%. The stainless steel of the present invention can be classified as Cu-based stainless steel by including 1.0% or more of copper.

As the content of copper increases, the phase transformation effect of copper increases, but its increase gradually decreases. If the copper content exceeds 4.0%, the effect of inhibiting the phase transformation is saturated. Since copper is an expensive element, the content of copper also affects the economics of stainless steel. Therefore, the upper limit of copper is set to 4.0% in order to secure the economical efficiency of the stainless steel within the range where the effect of suppressing the phase transformation of copper is saturated.

(7) Molybdenum (Mo, molybdenum): not more than 0.03%

(8) phosphorus (P, phosphorus): not more than 0.04%

(9) Sulfur (S, Sulfer): not more than 0.04%

(10) Nitrogen (N, Nitrogen): not more than 0.03%

Since molybdenum, phosphorus, sulfur and nitrogen cure the stainless steel with the elements originally contained in the steel semi-finished product, it is desirable to keep them as low as possible. Molybdenum can improve the corrosion resistance of stainless steel, but it should be controlled to 0.03% or less because it has a disadvantage of hardening stainless steel rather than improving corrosion resistance. Phosphorus, sulfur and nitrogen are set to 0.04%, 0.04% and 0.03% or less, respectively, in order to prevent the hardening of stainless steel.

2. Matrix structure of stainless steel

The matrix structure of the stainless steel may be determined according to the composition and / or heat treatment conditions. Typically, the base structure of stainless steel is divided into austenite, ferrite and martensite. The physical properties of stainless steel vary depending on each base structure.

The stainless steel of the present invention has an austenitic matrix structure. The austenite corresponds to a base structure exhibiting resistivity and hardness characteristics compared to ferrite or martensite. Further, the average particle size to be described later is a limitation which is satisfied by growing the crystal size of the stainless steel. When the three base structures are treated under the same conditions to grow the crystal size, austenite has the largest low strength and low hardness effect.

The base structure of stainless steel is most preferably made of only austenite. However, since it is very difficult to control the base structure of stainless steel with only austenite, stainless steel may contain not only austenite but also other base structures. In this case also, for low strength and low hardness characteristics, the stainless steel should have an austenite base structure of 90% or more, preferably 99% or more, based on the grain size area. For example, if stainless steel has an austenitic matrix structure and a delta ferritic matrix structure, the stainless steel should have an austenitic matrix structure of 99% or more and a delta ferrite matrix structure of 1% or less based on the grain size area.

The physical properties of stainless steel vary depending on the base structure. In order to evaluate the physical properties of the stainless steel according to the base structure, Example 1 and Example 2 are set and compared with each other.

2A is a microstructure photograph showing a stainless steel according to Example 1 of the present invention. FIG. 2B is a microstructure photograph showing the stainless steel according to the second embodiment of the present invention. FIG.

The stainless steels of Example 1 and Example 2 were previously described in [1. Composition of stainless steel]. In addition, the stainless steels of Examples 1 and 2 [3. Average particle size of stainless steel]]. However, the stainless steel of Example 1 has only an austenite base structure of 99% or more and a ferrite base structure of 1% or less based on the grain size area, whereas the stainless steel of Example 2 has only an austenite base structure.

The results of comparing the stainless steels of Examples 1 and 2 with each other are shown in Table 1 below.

Kinds
Mechanical properties Yield strength
[MPa] The tensile strength
[MPa] Hardness
[Hv] Elongation
[%] Example 1 Stainless steel
(Austenite + delta ferrite) 180 500 120 52 Example 2 Stainless steel
(Austenite) 160 480 110 60

It can be seen from Table 1 that the stainless steel of Example 2 has lower strength and lower hardness than the stainless steel of Example 1. In addition, the stainless steel of Example 2 has a higher elongation than the stainless steel of Example 1. From this, in order to realize low strength and low hardness properties of stainless steel, it is preferable that stainless steel is made only of an austenite base structure. As the ratio of the delta ferrite base structure increases, the strength and hardness of the stainless steel increases, so that the ratio of the stainless steel to the delta ferrite base structure should be 1% or less based on the grain size area.

Even when the stainless steel has a delta ferrite base structure of 1% or less, it is advantageous to realize low strength and low hardness because the delta ferrite is locally distributed (densely packed) locally rather than uniformly distributed throughout the crystal grains.

3. Average diameter of stainless steel (average diameter)

The average grain size of the stainless steel may be determined by composition and / or heat treatment conditions. The average particle size of the stainless steel influences the strength and hardness of the stainless steel. For example, the smaller the average particle size, the greater the strength and hardness of the stainless steel, and the larger the average particle size, the smaller the strength and hardness of the stainless steel.

In the present invention, the average particle size of the stainless steel is limited to 30 to 60 占 퐉 in order to secure the low strength and low hardness characteristics of the stainless steel. The average grain size of typical austenite is less than 30 탆. Therefore, the average particle size should be increased to 30 μm or more through the manufacturing process and the heat treatment. According to the American Society for Testing and Materials (ASTM) standard, an average particle size of 30 to 60 μm corresponds to a grain size number of 5.0 to 7.0. In contrast, an average particle size smaller than 30 μm corresponds to an ASTM particle size number of 7.5 or greater.

If the average particle size of the stainless steel is smaller than 30 占 퐉 or the particle size of the stainless steel is larger than 7.0, it does not have the characteristics of low strength and low hardness required in the present invention. Particularly, the average particle size (or particle size number) of stainless steels is a key factor determining the low strength and low hardness characteristics of stainless steels.

The physical properties of stainless steel vary depending on the average particle size of the stainless steel. In order to evaluate the physical properties of stainless steel according to the average particle size, Comparative Examples and Examples are respectively set and compared with each other.

Comparative Example 1 is copper, Comparative Examples 2 to 5 are stainless steels having a particle size of 7.5 or more, and Example 3 of the present invention is stainless steel having a particle size of 6.5.

3 is a microstructure photograph showing the stainless steel according to Comparative Example 2. Fig. The stainless steel of Comparative Example 2 has an austenite base structure of 99% or more and a delta ferrite base structure of 1% or less based on the grain size area, and has an average grain size (about 15 to 17 탆) corresponding to ASTM grain size No. 9 .

4 is a microstructure photograph showing a stainless steel according to Comparative Example 3. Fig. The stainless steel of Comparative Example 3 has an austenite base structure of 99% or more and a delta ferrite base structure of 1% or less based on the grain size area, and has an average grain size (about 24 to 27 탆) corresponding to ASTM grain size number 7.5 .

5 is a microstructure photograph showing a stainless steel according to Comparative Example 4. Fig. The stainless steel of Comparative Example 4 has only an austenitic matrix structure and has an average particle size corresponding to ASTM Particle No. 9.

6 is a microstructure photograph showing stainless steel according to Comparative Example 5. Fig. The stainless steel of Comparative Example 5 has only an austenitic matrix structure and has an average particle size corresponding to ASTM grain size number 7.5.

And an average particle size (about 39 to 40 mu m) corresponding to the ASTM particle size number 6.5 of Example 3. The microstructure photograph of the stainless steel according to Example 3 can be expected to be substantially the same or similar to the microstructure photographs of Example 1 or Example 2 shown in FIG. 2A or FIG. 2B (for example, Example 1 or Example The ATSM particle number of Example 2 is 6.5).

7 is a stress-strain graph in which physical properties of the stainless steel of Example 3 were evaluated. The abscissa of the graph represents the displacement (mm) of the stainless steel, and the ordinate of the graph represents the stress (N / mm ² ) applied to the stainless steel.

As can be seen from the graph, the yield strength of the stainless steel was measured to be about 156.2 MPa, and the tensile strength of the stainless steel was measured to be about 470 MPa.

As a result of evaluating the physical properties of the stainless steel of the present invention, even if the composition, base texture, and average particle size were slightly changed from Example 3, the yield strength was less than about 160 MPa, the tensile strength was less than about 480 MPa, hardness and an elongation of 60% or more. Further, the stainless steel of the present invention was measured to have physical properties within the above range irrespective of whether the shape thereof is a tube or a sheet.

The results of comparing the stainless steels of the present invention with other comparative examples are shown in Table 2 below.

Kinds
Mechanical properties Yield strength
[MPa] The tensile strength
[MPa] Hardness
[Hv] Elongation
[%] Comparative Example 1 Copper (C1220T) piping 100 270 100 45 or more Comparative Example 2 - 5 Stainless steel (particle number 7.5 or higher) 200 inside and outside 500 inside and outside 130 inside and outside Over 50 Invention Stainless steel (particle size 5.0 to 7.0) 160 inside and outside 480 inside and outside 120 or less 60 or more

In Comparative Example 1, the copper pipe had a yield strength of 100 MPa, a tensile strength of 270 MPa, a hardness of 100 Hv, and an elongation of 45% or more. Since copper has low strength and low hardness properties, it is commercialized as a refrigerant pipe for an air conditioner or the like. However, as described above, copper has problems of reliability due to corrosion and inadequacy of piping to new refrigerants.

The stainless steels of Comparative Examples 2 to 5 have a composition and a base structure similar to those of the stainless steel of the present invention, but have a grain size number of 7.5 or more. The stainless steels of Comparative Examples 2 to 5 had a yield strength of about 200 MPa, a tensile strength of about 500 MPa, a hardness of about 130 Hv, and an elongation of 50% or more. The stainless steels of Comparative Examples 2 to 5 having grain size numbers larger than 7.5 have excessively high strength and high hardness properties compared to copper. Therefore, although the stainless steels of Comparative Examples 2 to 5 can solve the problem of copper due to corrosion, they have a problem of inadequate processability to be processed into a refrigerant pipe.

In contrast, the stainless steel of the present invention has a yield strength of about 160 MPa, a tensile strength of about 480 MPa, a hardness of about 120 Hv or less, and an elongation of 60% or more. Therefore, the stainless steel of the present invention can solve not only the problem of workability raised in the stainless steels of Comparative Examples 2 to 5 but also the corrosion problems raised in the copper of Comparative Example 1. Further, since the stainless steel of the present invention has sufficient high pressure resistance characteristics, it is suitable for use as a pipe for high-pressure new refrigerant such as R32.

The thermal conductivity of copper is 388 W / mK, and the thermal conductivity of stainless steel is 16.2 W / mK. The higher the thermal conductivity of the material, the greater the heat loss during the flow of the refrigerant, so the higher the thermal conductivity of the material, the lower the efficiency of the cycle. Since the thermal conductivity of stainless steel is only about 4% of copper, constructing the piping of the cycle with stainless steel can improve the efficiency of the cycle by reducing heat loss.

As described above, the stainless steel of the present invention has low strength and low hardness properties at the copper material level, while having high corrosion resistance and high withstand voltage characteristics which are inherent characteristics of stainless steel. Therefore, it has a sufficient condition to be applied to the piping by solving the problem of workability.

Hereinafter, the piping made of the stainless steel of the present invention, the system including the piping, and the like will be described.

8 is a block diagram showing a refrigeration cycle of an air conditioner according to an embodiment of the present invention.

The air conditioner 100 is an example of a system having piping 131, 132, 133, and 134 made of stainless steel, that is, a stainless steel piping. Therefore, the system including the stainless steel pipes 131, 132, 133, and 134 is not necessarily limited to the air conditioner 100, and pipes of the stainless steel pipes 131, 132, 133, It corresponds to the system described in the present invention.

The air conditioner (100) includes an outdoor unit (110) and an indoor unit (120). One or more indoor units 120 may be connected to one outdoor unit 110 and the indoor unit 120 and the connected outdoor unit 110 may operate as one system. In addition, the air conditioner 100 may be operated only in a cooling-only mode or a heating-only mode by selectively operating the refrigeration cycle in only one direction. Alternatively, the air conditioner 100 may selectively operate the refrigeration cycle in both directions through a four- Or the heating mode may be operated simultaneously.

The outdoor unit 110 may include a compressor 111, an outdoor heat exchanger 112, and an inflator 113.

The compressor 111 is configured to compress the refrigerant into a high-temperature, high-pressure gas. The compressor 111 can be operated by receiving power. Also, in the present invention, the compressor is a concept including an engine that operates by receiving fuel. And constitutes a refrigeration cycle, and corresponds to the compressor 111 defined in the present invention if the refrigerant is compressed.

The outdoor heat exchanger 112 performs heat exchange with the outdoor air with the gas refrigerant compressed at the high temperature and high pressure in the compressor 111 during the cooling operation to condense it into the low temperature and high pressure liquid. An outdoor fan 112a is installed at one side of the outdoor heat exchanger 112 to facilitate heat exchange in the outdoor heat exchanger 112. The outdoor fan 112a sucks the outdoor air and blows air toward the outdoor heat exchanger 112. [

The inflator 113 controls the temperature of the refrigerant discharged from the outdoor heat exchanger 112 to control the degree of superheat during cooling operation and the degree of supercooling during heating operation.

The indoor unit 120 may include an indoor heat exchanger 121 and an indoor fan 121a. The indoor heat exchanger 121 evaporates the low-temperature low-pressure refrigerant that has passed through the inflator 113 during the cooling operation to convert it into a low-temperature and low-pressure gas. The indoor fan 121a circulates indoor air so that heat exchange is smoothly performed in the indoor heat exchanger 121. [

The compressor 111, the outdoor heat exchanger 112, the inflator 113, and the indoor heat exchanger 121 are sequentially connected by piping 131, 132, 133, and 134. The compressor 111, the outdoor heat exchanger 112, the inflator 113 and the indoor heat exchanger 121 which are sequentially connected by the pipes 131, 132, 133 and 134 form a refrigeration cycle. Since the refrigerant flows along the pipes 131, 132, 133 and 134, the pipes 131, 132, 133 and 134 form the refrigerant flow path. In addition, since the outdoor heat exchanger 112 and the indoor heat exchanger 121 perform heat exchange while the refrigerant flows along the flow path, the outdoor heat exchanger 112 and the indoor heat exchanger 121 also form a refrigerant flow path. The stainless steel of the present invention may be applied to the piping 131, 132, 133 and 134 and may be applied to the outdoor heat exchanger 112 or the outdoor heat exchanger 112.

In the refrigeration cycle of Fig. 8, the indoor heat exchanger 121 is provided on the upstream side of the compressor 111, and the outdoor heat exchanger 112 is provided on the downstream side of the compressor 111. [ Here, the concept of the upstream side and the downstream side is set based on the refrigerant flow in the cooling mode.

A valve or an accumulator may be additionally provided between the compressor 111 and the indoor heat exchanger 121 and a valve or a muffler may be added between the compressor 111 and the outdoor heat exchanger 112 As shown in FIG. The valve is for controlling the flow of the refrigerant and is intended to prevent a phenomenon that the liquid refrigerant that has not vaporized from the accumulator flows into the compressor 111 and the efficiency of the refrigerating cycle is lowered. To reduce the generated noise.

In the present invention, an apparatus which is directly connected to the compressor 111 by piping among the devices constituting the refrigeration cycle and forms a part of the refrigeration cycle together with the compressor 111 is referred to as a refrigeration cycle component. For example, in FIG. 8, since the indoor heat exchanger 121 and the outdoor heat exchanger 112 are directly connected to the compressor 111 by piping, they correspond to the refrigeration cycle components. If a valve or an accumulator is installed between the compressor 111 and the indoor heat exchanger 121, the valve or the accumulator corresponds to the refrigeration cycle component. Similarly, when a valve or a muffler is installed between the compressor 111 and the outdoor heat exchanger 112, the muffler corresponds to the refrigerating cycle component.

The refrigeration cycle components together with the compressor 111 form part of the refrigeration cycle. The refrigerating cycle components are installed on at least one of the upstream side and the downstream side of the compressor 111 based on the flow of the refrigerant. The refrigerating cycle component provided on the upstream side of the compressor 111 is supplied to the compressor 111 and the refrigerating cycle component provided on the downstream side of the compressor 111 is supplied with the refrigerant from the compressor 111.

9 is a partial view showing the air conditioner of the present invention.

9, a compressor 211 and an accumulator 212 are shown. The compressor 211 has already been described above in Fig. The accumulator 212 corresponds to an example of a refrigeration cycle component. The refrigerating cycle component is described as a refrigeration cycle device that is directly connected to the compressor 211 by piping. Direct connection with the compressor 211 means that there is no other configuration except for the piping between the compressor 211 and the refrigeration cycle component.

The accumulator 212 prevents the liquid refrigerant, which has not evaporated in the evaporator (corresponding to the indoor heat exchanger described in FIG. 1), from flowing into the compressor 211. Here, the accumulator 212 is described as an example of a refrigeration cycle component, but the description other than the essential structure and function of the accumulator 212 can be applied to other refrigeration cycle components.

In the present invention, the pipe connecting the compressor 211 and the accumulator 212 is made of stainless steel. Since the accumulator 212 is an example of a refrigeration cycle component, the piping connecting the compressor 211 and the refrigeration cycle component is made of stainless steel. Therefore, the pipe can be named as the stainless steel pipe 230.

The stainless steel pipe 230 has a higher resistance to corrosion than a conventional copper pipe, and thus has a longer life than a copper pipe (copper pipe). Also, the stainless steel pipe 230 has an advantage that it has a higher strength than the copper pipe.

One end 230a is connected to the compressor 211 and the other end 230b is connected to the accumulator 212 so that the stainless steel pipe 230 forms a single pipe between the compressor 211 and the accumulator 212. [ A single pipe is meant to be one, and it must be distinguished from the collection of several parts.

One end 230a of the stainless steel pipe 230 is connected to the compressor 211 and the other end 230b is connected to the accumulator 212 in order for the stainless steel pipe 230 to form a single pipe. This is because the other end 230b of the stainless steel pipe 230 is not a single pipe if it is connected to another pipe rather than the accumulator 212.

The stainless steel pipe 230 has a corrugated portion 230e in part to attenuate vibration transmitted from the compressor 211 to the accumulator 212. In the compressor 211, vibration is inevitably generated during the compression of the refrigerant, and the vibration transmitted along the mechanical parts is mainly transmitted along the plane. Therefore, if the stainless steel pipe 230 has the corrugated portion 230e formed by alternately arranging the mountain 230e1 and the valleys 230e2 alternately, the surface of the compressor (the outer surface of the stainless steel pipe) The vibration transmitted to the accumulator 212 can be attenuated.

At least a portion of the stainless steel pipe 230 is machined and formed integrally with the remainder of the stainless steel pipe 230. The corrugation 230e may be formed by a hydro-forming process. Hydroforming refers to a process of forming a corrugated portion 230e while contracting the length of a straight pipe by applying a strong water pressure to the straight pipe, rather than welding the various types of unit parts separately after pressing them into a press. When the corrugated part 230e is formed by the hydroforming process, the corrugated part 230e becomes a part of the stainless steel pipe 230 and is formed integrally with the remaining part of the stainless steel pipe 230. [

For the purpose of attenuating vibration such as the corrugation 230e, the stainless steel pipe 230 may have a curved region 230d. The bent region 230d indicates a non-straight region in the stainless steel pipe 230. [ The bent region 230d may be formed by bending at least a part of the stainless steel pipe 230. [ As the number of bent regions 230d increases, the structure of the stainless steel pipe 230 becomes complicated, but the vibration transmitted from the compressor 211 to the accumulator 212 can be attenuated.

The corrugated portion 230e may be formed in the straight region 230c of the stainless steel pipe 230 or may be formed in the curved region 230d or may be formed in both the straight region 230c and the curved region 230d have. The corrugated portion 230e may also be formed over the straight region 230c and the curved region 230d of the stainless steel pipe 230.

The stainless steel pipe 230 of the present invention is formed by integrating the corrugated portion 230e with the rest of the stainless steel pipe 230 so that the corrugated portion of the corrugated portion 230e, (Not shown). Particularly, when the corrugated portion 230e is formed in the curved region 230d, noise may be generated somewhat. However, as described later, the corrugated portion 230e of the present invention has a structure in which the corrugation portion 230e is very closely- The pressure drop of the refrigerant generated due to the formation in the curved region 230d is very limited as compared with the conventional flexible pipe.

In order to manufacture the stainless steel pipe 230 having both the corrugated portion 230e and the bent region 230d, the corrugated portion 230e is first formed in the straight pipe by the hydroforming process, .

Since the corrugated portion 230e is formed integrally with the remaining portion of the stainless steel pipe 230, the joint portion can be removed from the pipe connecting the compressor 211 and the accumulator 212. [ The presence of joints means that there are discontinuities in the piping, and the discontinuities have cumulative stresses. Therefore, the seam can be a source of fracture occurrence, which results in lowering the durability and mechanical reliability of the pipe.

However, since the stainless steel pipe 230 of the present invention does not have a separate joint such as a conventional flexible pipe, there is no discontinuity between the compressor 211 and the accumulator 212. Therefore, the stainless steel pipe 230 of the present invention is a structure that can prevent stress from concentrating only on a certain area.

10 is a sectional view partially showing the corrugation 230e of the stainless steel pipe 230 shown in Fig.

The corrugated portion 230e is formed by repeatedly alternating the mountain 230e1 and the valley 230e2. The alternation means alternately arranged such as a mountain 230e1, a bone 230e2, a mountain 230e1, a bone 230e2, a mountain 230e1, and a bone 230e2.

In the stainless steel pipe 230 of the present invention, each of the mountains 230e1 is spaced from each other, and each valley 230e2 is also spaced from each other. This should be distinguished from the structure in which the mountain 230e1 and the valley 230e2 are each formed in a spiral shape. If the mountains 230e1 and the valleys 230e2 are respectively formed in a spiral shape, the mountains 230e1 are not separated from each other and the valleys 230e2 are not separated from each other.

If the mountains 230e1 are spaced apart from each other and the valleys 230e2 are spaced apart from each other, a curved region can be formed with only a relatively small external force, and there is an advantage of reducing pressure drop and alleviating noise generation. These two effects will be described below.

When the mountain 230e1 and the valley 230e2 have the same structure as the present invention, when the external force is applied to the linear region formed with the corrugated portion 230e to form a curved region, the pipe can be bent by applying a relatively small external force . This is because each of the mountains 230e1 protrudes along a plane orthogonal to the longitudinal direction of the stainless steel pipe 230. The outermost circumference of the mountain 230e1 is orthogonal to the longitudinal direction of the stainless steel pipe 230, for example. Or in a direction orthogonal to the outer circumferential surface of the stainless steel pipe 230.

Accordingly, the mountain 230e1 and the mountain 230e1 are bent away from one side of the stainless steel pipe 230, and the mountain 230e1 and the mountain 230e1 are bent toward each other at the other side. And the mountain 230e1 and the valley 230e2 do not interfere with the warping when an external force is applied with both hands.

At this time, one side of the stainless steel pipe 230 refers to a portion denoted by 230d in FIG. 9, and the other side refers to a portion denoted by 230d 'in FIG. However, the wrinkle portion 230e is not shown in the portion denoted by 230d and the portion denoted by 230d 'in Fig. However, it is assumed that the corrugated part 230e is formed to apply the relatively small external force to bend the stainless steel pipe 230.

Unlike the present invention, in the structure in which the mountain and the valleys are respectively formed in a spiral shape, the mountain and the valley cross each other obliquely in the direction of applying the external force with both hands. For example, when holding a pipe with both hands and collecting both hands to apply an external force, the direction of applying the external force means a direction of collecting from left to right. Mountains and valleys cross this direction at right angles, but at an acute angle or obtuse angle. As a result, the mountain and the valley of the helical structure interfere with the bending of the pipe, and the pipe can be bent only when a relatively large external force is applied.

On the other hand, the pressure of the refrigerant flowing through the pipe is affected by the roughness of the inner peripheral surface of the pipe. The rougher the inner circumferential surface is, the more the resistance element of the refrigerant flow is, and the pressure drop of the refrigerant becomes worse and the vibration and the noise become larger due to the increase of the resistance of the flow path. On the other hand, the closer the inner circumferential surface is to the smooth surface, the less the pressure drop of the refrigerant, and the smaller the vibration and noise.

The fact that the cross section inside the pipe does not maintain the correct circle means that there are many elements that act as a resistance of the refrigerant flow. If a large number of elements act as a resistance of the refrigerant flow, the pressure drop of the refrigerant passing through the piping and the generation of noise are caused.

Therefore, in order to relieve the pressure drop and the noise generation of the refrigerant, the cross section of the inside of the pipe must be maintained in an accurate circle. Whether the cross section inside the pipe maintains an accurate circle can be evaluated by roundness. Out-of-roundness refers to a dimension deviating from a geometrically accurate circle, and means a measure of how far all the points at the same distance from the center deviate from the correct circle.

If the mountain 230e1 and the valley 230e2 have the same spacing structure as the present invention, even if an external force is applied to a straight line region formed with the corrugation 230e, the circularity change can be suppressed. Therefore, the roundness change on the inner peripheral surface of the wrinkled portion 230e formed in the curved region is relatively small.

On the contrary, if the mountain and the valley have a spiral structure, it is difficult to suppress the change in roundness even if the external force is applied to the straight region formed with the wrinkled portion to form a curved region. Therefore, the roundness change is relatively large at the inner peripheral surface of the wrinkled portion formed in the curved region.

The fact that the roundness change is relatively small means that the cross-section of the inside of the pipe has a more accurate circle shape. Therefore, the corrugated portion 230e of the present invention can reduce the pressure drop of the refrigerant and the generation of noise in the curved region It is effective.

In the stainless steel pipe 230 of the present invention, the acid 230e1 is formed by 2 to 5 lengths of 1 cm along the longitudinal direction of the stainless steel pipe 230. Since the valley 230e2 is formed between the mountain 230e1 and the mountain 230e1, if two to five mountains 230e1 are formed for each length of 1cm, one to four valleys 230e2 are formed.

The formation of 2 to 5 of the mountains 230e1 in the length of 1cm means that the mountain 230e1 and the valley 230e2 of the wrinkle portion 230e are formed very closely. When the mountain 230e1 and the valley 230e2 are formed in this manner, the inner circumferential surface of the corrugated portion 230e becomes closer to the smooth surface, so that the pressure drop of the refrigerant passing through the stainless steel pipe 230 can be reduced. Also, when the mountain 230e1 and the valley 230e2 are closely formed, the flexibility (flexibility) of the stainless steel pipe 230 is increased, and the effect of damping transmission of vibration and noise is increased.

It is difficult to manufacture a pipe having a structure in which more than five hills 230e1 are present within a length of 1 cm. In addition, it is difficult to manufacture a pipe having the hills 230e1 and the hills 230e1 when an external force is applied to a straight- So that it acts as a resistor. Conversely, the structure in which the number of the hills 230e1 is less than two within a length of 1cm has a small effect of reducing the external force required when an external force is applied to a straight region formed with the wrinkled portion 230e to form a curved region. In addition, since the effect of vibration damping is also small, it is difficult to sufficiently relieve the stress.

Considering the thickness of the corrugated portion 230e, the distance D between the mountain 230e1 and the mountain 230e1 should be 8 mm or less in order for two or more mountains 230e1 to exist within a length of 1 cm. If the distance D between the mountain 230e1 and the mountain 230e1 exceeds 8mm, there may be only one mountain 230e1 within a length of 1cm depending on the thickness of the stainless steel pipe 230. [

Referring to FIG. 10, the thickness of the stainless steel pipe 230 in the mountain 230e1 is indicated by T1. The thickness of the stainless steel pipe 230 in the trough 230e2 is indicated by T2. The thickness of the stainless steel pipe 230 between the mountain 230e1 and the valley 230e2 is represented by T3. And the region without the corrugated portion 230e is indicated as having a thickness of T4. Here, thickness refers to the difference between the outer diameter and the inner diameter. T4 may vary depending on the design, but due to the characteristics of the stainless steel material, it is possible to have a sufficient stiffness even with a thickness of 0.5 to 0.8 mm.

The thicknesses T1, T2 and T3 of the corrugated portion 230e and the region T4 without corrugated portion 230e have a thickness difference of more than 0% and 5% or less. For example, if the thickness of the wrinkled portion 230e is t, the region without the wrinkled portion 230e has a thickness of 0.95t to 1t. In the process of forming the corrugated part 230e, the length of the stainless steel pipe 230 may be shortened by hydroforming, and the thickness may be reduced. However, when the difference is within 5%, it means that the thickness of the wrinkled portion 230e and the thickness of the region without the wrinkled portion 230e are almost constant. The fact that the thickness is almost constant means that there is almost no element acting as a resistance, so that the noise generation and the pressure drop phenomenon inside the stainless steel pipe 230 can be suppressed.

The strength of the corrugated portion 230e can be sufficiently secured if the thickness of the corrugated portion 230e is substantially equal to the thickness of the remaining portion of the stainless steel pipe 230. [ Therefore, the stainless steel pipe 230 of the present invention does not require a joint for joining the wire braid unless the wire braid described in the Background of the Invention section is required. Since the joint portion is also a kind of discontinuous portion, the stainless steel pipe 230 of the present invention, which does not require a wire braid, is capable of preventing stress concentration.

T1, T2, and T3 also have a thickness difference of more than 0 and 2% or less. This means that the thickness is almost constant at each position of the corrugated portion 230e. If the thickness of the corrugated portion 230e is substantially constant at each position of the corrugated portion 230e, the resistance formed on the inner circumferential surface of the corrugated portion 230e can be relaxed, thereby relieving the pressure drop of the coolant, do. Furthermore, transmission of vibration and noise can also be attenuated.

The reason that T1 to T4 can have a substantially constant thickness is that the corrugated portion 230e is formed integrally with the remaining portion of the stainless steel pipe 230.

The remaining portion of the stainless steel pipe 230 excluding the corrugated portion 230e can be expected to have the same outer diameter and inner diameter as the straight region without the corrugation portion 230e or the bent region without the corrugated portion 230e. However, the outer diameter and inner diameter at the corrugated portion 230e may not be the same as the rest of the stainless steel pipe 230. [ This is because the corrugated portion 230e is formed by processing a linear region.

In the remaining part of the stainless steel pipe 230 excluding the corrugated part 230e, the outer diameter can be represented by O1 and the inner diameter can be represented by I1. The outer diameter at the valley 230e2 may be denoted by O2 and the inner diameter at the valley 230e2 may be denoted by I2. Also, the outer diameter at the mountain 230e1 may be denoted by O3. The difference between the outer diameter O3 in the mountain 230e1 and the outer diameter O2 in the valley 230e2 can be expressed as H (H = O3-02). H means the height of the mountain 230e1.

In the present invention, O1 and O2 have a size difference of more than 0 and 2% or less. Also, I1 and I2 have a size difference of more than 0 and less than 2%. This is because the outer diameter before forming the wrinkled portion 230e is substantially the same as the outer diameter after the wrinkled portion 230e is formed and the inner diameter before forming the wrinkled portion 230e is the same as the inner diameter after forming the wrinkled portion 230e And there is no substantial difference.

And the outer diameter at the mountain 230e1 may be appropriately designed according to the outer diameter of the stainless steel pipe 230. [ The outer diameter of the appropriate acid 230e1 is shown in Table 3 below. All units in the values given in Table 3 are in mm.

Outer diameter (T4) The inner diameter (I1) Outer diameter of mountain (O3) The height of the mountain (H) 15.88 14.6 21.48 - 22.28 2.8-3.2 18.2 17 23.8 - 24.6 2.8-3.2 19.05 17.8 24.65 - 25.45 2.8-3.2 20 18.8 25.6 - 26.4 2.8-3.2 26 24.4 31.6 - 32.4 2.8-3.2 30 28.8 35.6 - 36.4 2.8-3.2 30.8 29.6 36.4 - 37.2 2.8-3.2 33 32 38.6 - 39.4 2.8-3.2 35 33.8 40.6 - 41.4 2.8-3.2 39 37.8 44.6 - 45.4 2.8-3.2 50.8 49.6 56.4 - 57.2 2.8-3.2

The height H of the mountain 230e1 is derived by dividing the number obtained by subtracting the outer diameter T4 of the region without the corrugation 230e from the outer diameter O3 of the mountain 230e1 in half. Referring to Table 3, the outer diameter O3 of the mountain 230e1 is designed in such a range that the height H of the mountain 230e1 can be in the range of 2.8 to 3.2 mm. This is because if the height of the mountain 230e1 is less than 2.8mm, the effect of relaxing the stress is insufficient. If the height of the mountain 230e1 is higher than 3.2mm, the possibility of breakage increases.

11A is a conceptual view showing a state in which two components of a refrigeration cycle are connected by a conventional piping having no corrugated portion.

And A and B are arbitrary components constituting the refrigeration cycle, respectively. A and B are arranged so as to be spaced apart from each other in a three-dimensional space, and are connected to each other by a pipe 30. One end (30a) of the pipe (30) is connected to A and the other end (30b) is connected to B. At least one of A and B may cause vibration and noise like a compressor.

The pipe 30 has a plurality of curved regions 30d1, 30d2, 30d3, 30d4, 30d5, and 30d6 to suppress the transmission of vibration from one of A and B to the other. The vibration is transmitted through the pipe 30, and the vibration transmission rate is particularly high in the linear region 30c than the curved regions 30d1, 30d2, 30d3, 30d4, 30d5, and 30d6. Conversely, transmission of vibration is relieved in the curved regions 30d1, 30d2, 30d3, 30d4, 30d5, and 30d6.

Therefore, in order to suppress transmission of the vibration, the pipe 30 must have a plurality of curved regions 30d1, 30d2, 30d3, 30d4, 30d5, and 30d6 as shown in FIG. 4A. However, although such a structure can mitigate the transmission of vibration, it requires not only a large installation space for the piping but also a disadvantage that the piping structure becomes excessively complicated.

FIG. 11B is a concept view showing a state where two components of the refrigeration cycle are connected to the stainless steel pipe 330 of the present invention having the corrugated portion 330e. 11A, A and B indicate two components of the refrigeration cycle, and installation positions of A and B in the three-dimensional space are the same as those shown in FIG. 4A.

It has been described that the corrugated portion 330e has the effect of damping the vibration. Therefore, when A and B are connected to the stainless steel pipe 330 of the present invention having the corrugated portion 330e, even if the stainless steel pipe 330 having a relatively simplified structure as compared with FIG. 11A is adopted, have. Therefore, by using the stainless steel pipe 330 of the present invention having the corrugated portion 330e, it is possible to connect A and B even with a relatively narrow installation space. For example, even if only a relatively small number of curved regions 330d are present, the corrugated portion 330e has a further excellent vibration damping effect.

Reference numerals 330a and 330b, which are not shown in FIG. 11B, indicate both ends of the stainless steel pipe, reference numeral 330c denotes a rectilinear region, and reference numeral 330d denotes a curved region.

12 is a concept showing a stainless steel pipe 430 according to another embodiment of the present invention.

The stainless steel pipe 430 may have copper bonding portions 430f and 430g on at least one of both ends 430a and 430b. The copper bonding portions 430f and 430g are made of copper (copper) having a shape of a relatively short straight pipe and are bonded to the outer circumferential surface or the inner circumferential surface of the stainless steel pipe 430. [

When the copper bonding portions 430f and 430g are joined to the outer circumferential surface of the stainless steel pipe 430, the copper bonding portions 430f and 430g have a size to surround the stainless steel pipe 430. [ Conversely, when the copper junctions 430f and 430g are bonded to the inner circumferential surface of the stainless steel pipe 430, the stainless steel pipe 430 has a size that covers the copper bonding portions 430f and 430g.

The piping connecting the compressor to the refrigeration cycle components is connected to the piping connection of the compressor and the piping connection (not shown) of the refrigeration cycle component. The piping connection portion is provided in the compressor or the refrigeration cycle component and indicates a portion that can be joined to the stainless steel piping 430. The pipe connection portion also has a shape of a pipe and may protrude outward from the compressor or refrigeration cycle component to be connected to the stainless steel pipe 430.

Bonding of different materials is more difficult than joining of the same materials, and since the pipe connection is generally made of copper, it may be difficult to directly join the stainless steel pipe 430.

The stainless steel pipe 430 of the present invention has the copper bonding portions 430f and 430g at least at one end to solve this difficulty. Since the copper bonding portions 430f and 430g are made of the same material as the pipe connecting portion, when the copper bonding portions 430f and 430g are formed, they can be more easily bonded to the pipe connecting portion.

The air conditioner described above is not limited to the configuration and the method of the embodiments described above, but the embodiments may be configured by selectively combining all or some of the embodiments so that various modifications may be made.

Claims (16)

A compressor configured to compress the refrigerant;
And a refrigerating cycle component that is provided on at least one of an upstream side and a downstream side of the compressor based on the flow of the refrigerant to supply the refrigerant to the compressor or to receive the refrigerant from the compressor, ; And
One end connected to the compressor and the other end connected to the refrigeration cycle component to form a single pipe between the compressor and the refrigeration cycle component and partially connected to the refrigeration cycle component to dampen vibrations transmitted from the compressor to the refrigeration cycle component And a stainless steel pipe having a corrugated portion,
Wherein at least a part of the stainless steel pipe is processed and integrally formed with the remaining part of the stainless steel pipe. The method according to claim 1,
Wherein the wrinkle portion is thinner than the region without the wrinkle portion by a thickness of 0 to 5% or less. The method according to claim 1,
The folded portion is formed by repeatedly alternating the mountains and the valleys,
The thickness (T1) of the stainless steel pipe, the thickness (T2) of the stainless steel pipe, and the thickness (T3) of the stainless steel pipe between the mountain and the valley are different from each other by more than 0 and 2% Characterized by an air conditioner. The method according to claim 1,
The folded portion is formed by repeatedly alternating the mountains and the valleys,
Wherein the acid is formed by 2 to 5 lengths of 1 cm along the longitudinal direction of the stainless steel pipe. The method according to claim 1,
The folded portion is formed by repeatedly alternating the mountains and the valleys,
Wherein the distance between two adjacent mountains is 8 mm or less. The method according to claim 1,
Wherein the stainless steel pipe has a curved region formed by bending at least a part of the region,
And the pleats are formed in the curved region. The method according to claim 1,
The stainless steel pipe may include:
Linear region; And
And a bent region formed by bending at least a part of the area of the stainless steel pipe,
Wherein the corrugated portion is formed over the straight region and the curved region. The method according to claim 1,
The folded portion is formed by repeatedly alternating the mountains and the valleys,
Wherein the mountains are spaced apart from each other, and the troughs are also spaced from each other. The method according to claim 1,
The folded portion is formed by repeatedly alternating the mountains and the valleys,
Wherein the acid protrudes in a circular shape along a direction orthogonal to an outer circumferential surface of the stainless steel pipe. The method according to claim 1,
The folded portion is formed by repeatedly alternating the mountains and the valleys,
Wherein a difference in distance between the outer diameter of the mountain and the outer diameter of the valley is 2.8 to 3.2 mm. The method according to claim 1,
The folded portion is formed by repeatedly alternating the mountains and the valleys,
Wherein the outer diameter of the valley has an outer diameter in a region without a wrinkle portion and a thickness difference of more than 0 and 2%
Wherein an inner diameter of the valley has an inner diameter in a region without a wrinkle portion and a thickness difference of more than 0% and 2% or less. The method according to claim 1,
Wherein the stainless steel pipe has a copper bonding portion at at least one end,
Wherein the copper-clad portion is made of copper having a shape of a straight pipe, and is bonded to the outer circumferential surface or the inner circumferential surface of the end portion. The method according to claim 1,
The stainless steel pipe may include:
C: not more than 0.03%, Si: not more than 1.7%, Mn: 1.5 to 3.5%, Cr: 15.0 to 18.0%, Ni: 7.0 to 9.0%, Cu: 1.0 to 4.0%, Mo: 0.03% , P: not more than 0.04%, S: not more than 0.04%, N: not more than 0.03%, the balance being Fe and unavoidable impurities,
An austenite matrix structure and an average diameter of 30 to 60 mu m. 14. The method of claim 13,
Wherein the stainless steel piping has an ASTM (Grain size No.) of 5.0 to 7.0. 14. The method of claim 13,
Wherein the stainless steel has an austenite matrix structure of 99% or more based on the particle size area. 16. The method of claim 15,
Wherein the stainless steel has a delta ferrite base structure of 1% or less based on the particle size area.

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