JP7846263B2 - Equipment piping connection structure and refrigeration cycle system - Google Patents

Description

This invention relates to a piping connection structure for equipment constituting a refrigeration cycle system, such as an air conditioner, and to a refrigeration cycle system itself.

Conventionally, refrigerant equipment is known as a component of air conditioners (refrigeration cycle systems, refrigeration devices), in which joint members (refrigerant piping) are joined to the main body of the equipment as refrigerant discharge and suction pipes (see, for example, Patent Document 1). In such refrigerant equipment, in most cases, the main body of the equipment and one end of the refrigerant piping are joined by brazing. When the refrigerant equipment is installed in a refrigerant circuit as a valve device, the other end of the refrigerant piping is joined to other pipes constituting the refrigerant circuit by brazing.

Japanese Patent Publication No. 2004-125238

In recent years, due to rising material costs, copper pipes are being replaced with stainless steel pipes. When using such stainless steel pipes as refrigerant piping, for example, during parts replacement, brazing the refrigerant pipes to the equipment body or other pipes requires the removal of oxide films, making the brazing process complicated and burdensome for workers.

The objective of this invention is to provide a refrigeration cycle system and equipment piping connection structure that allows stainless steel refrigerant piping to be brazed to the equipment body and other piping while reducing the workload.

The present invention relates to an equipment piping connection structure comprising a refrigerant equipment constituting a refrigeration cycle for circulating a refrigerant, wherein the refrigerant equipment comprises an equipment body and a stainless steel refrigerant pipe joined to the equipment body, the equipment body and one end of the refrigerant pipe are brazed together with brazing material, a plating layer is provided on at least one of the inner and outer circumferential surfaces in a predetermined range including the other end of the refrigerant pipe, the melting point of the brazing material is lower than the melting point of the plating layer, and the refrigerant pipe is a first refrigerant pipe. The end of the second refrigerant pipe is joined to the other end of the first refrigerant pipe by internal or external insertion, the opposing surface of the second refrigerant pipe facing the inner or outer circumferential surface of the first refrigerant pipe is formed of a metal of the same material or a similar material as the plating layer, the brazing material used to braze the one end of the first refrigerant pipe to the main body of the equipment is the first brazing material, the second refrigerant pipe is brazed to the other end of the first refrigerant pipe using the second brazing material, and the melting point of the second brazing material is lower than the melting point of the first brazing material.

This equipment piping connection structure allows for brazing the other end of the refrigerant piping to other pipes with reduced workload by appropriately selecting the material of the plating layer applied to a predetermined range including the other end of the stainless steel refrigerant piping, in accordance with the material of other pipes. In this case, with the above-described refrigerant equipment, the melting point of the brazing material used for brazing one end of the refrigerant piping to the equipment body is lower than the melting point of the plating layer. Therefore, the heat generated during brazing between one end of the refrigerant piping and the equipment body prevents the plating layer on the other end from melting or degrading. Consequently, brazing between one end of the refrigerant piping and the equipment body can be performed using methods such as furnace brazing, which have little concern regarding the impact on the plating layer and require less workload, thereby enabling hermetically sealed joining of the equipment body and the stainless steel refrigerant piping. Furnace brazing is a method in which the entire refrigerant piping and equipment body to be brazed are placed in a furnace filled with a high-temperature atmosphere (e.g., a hydrogen atmosphere) that can remove the oxide film, and brazing is performed in this furnace. This type of furnace brazing requires less labor than methods such as burner (torch) brazing, which involves manually applying flux to remove the oxide film. Thus, the above-described equipment piping connection structure allows for brazing stainless steel refrigerant piping to the equipment body and other piping while minimizing the labor burden.

Here, the brazing material is a metallic material containing two or more metals, and is an alloy material having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature, or an alloy material having a eutectic temperature where the solidus temperature and liquidus temperature coincide. The plating layer is formed by plating of a single metal having a single melting point, and it is preferable that the solidus temperature or eutectic temperature of the brazing material is lower than the melting point of the plating layer.

This configuration allows for the use of alloy materials as brazing materials, thereby expanding the range of brazing material options. Furthermore, by setting the solidus temperature or eutectic temperature of the brazing material lower than the melting point of the plating layer, melting or alteration of the plating layer at the other end can be effectively suppressed during brazing of one end of the refrigerant piping to the equipment body.

Furthermore, it is even more preferable that the brazing material is an alloy material having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature, and that the liquidus temperature of the brazing material is lower than the melting point of the plating layer.

For example, when brazing using alloy materials having the two melting points mentioned above as brazing material, it is sometimes desirable to perform brazing at a temperature exceeding the liquidus temperature of the brazing material from the viewpoint of the brazing material's flowability. With the above configuration, even when brazing is performed at such temperatures, the liquidus temperature of the brazing material is lower than the melting point of the plating layer, thus effectively suppressing melting and alteration of the plating layer.

Furthermore, as described above, the plating layer is formed by a plating mainly composed of copper, and the brazing material is mainly composed of copper, or mainly composed of copper and silver.

This configuration allows for reliable brazing connections to copper or copper-plated pipes, which are often the intended destinations for the other end of refrigerant piping. Furthermore, during brazing, melting or deterioration of the plating layer at the other end can be effectively avoided.

Furthermore, as described above, the equipment piping connection structure of the present invention is characterized in that it comprises the refrigerant equipment described above, the refrigerant piping is a first refrigerant piping, the end of a second refrigerant piping is inserted or inserted into the other end of the first refrigerant piping and joined, and the opposing surface of the second refrigerant piping that faces the inner or outer circumferential surface of the first refrigerant piping is formed of a metal of the same material or a similar material as the plating layer.

According to this equipment piping connection structure, since the opposing surface of the second refrigerant piping, which is the connection point for the other end of the first refrigerant piping, is formed of a metal of the same material or a similar material as the plating layer, brazing between this other end and the connection point can be performed with even less workload.

Furthermore, it is preferable that the second refrigerant piping is formed of a metal of the same material or a similar material as the plating layer.

This configuration allows the plating layer of the first refrigerant pipe and the opposing surface of the second refrigerant pipe to be made of the same material or a similar material.

Furthermore, it is preferable that the plating layer is a first plating layer, and that at least the opposing surface of the second refrigerant pipe is provided with a second plating layer formed of the same material or a similar material as the first plating layer, and that the second refrigerant pipe is made of stainless steel.

This configuration also allows the plating layer of the first refrigerant pipe and the opposing surface of the second refrigerant pipe to be made of the same or a similar material. Furthermore, this configuration increases the degree of freedom in selecting the material of the second refrigerant pipe.

Furthermore, as described above, in the configuration in which the second plating layer is provided, it is even more preferable that the second refrigerant piping is made of stainless steel.

This configuration allows for cost reduction by using the same or similar material for the plating layer of the first refrigerant pipe and the opposing surface of the second refrigerant pipe, while employing inexpensive stainless steel piping for the second refrigerant pipe.

Furthermore, as described above, the brazing material used to braze one end of the first refrigerant piping to the equipment body is the first brazing material, and the second refrigerant piping is brazed to the other end of the first refrigerant piping using the second brazing material. It is preferable that the melting point of the second brazing material is lower than that of the first brazing material.

This configuration effectively suppresses the melting and deterioration of the first brazing material at the joint between one end of the first refrigerant pipe and the equipment body, due to the heat generated during brazing between the other end of the first refrigerant pipe and the second refrigerant pipe.

Furthermore, both the first brazing material and the second brazing material are metallic materials containing two or more metals, and are alloy materials having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature, or alloy materials having a eutectic point temperature where the solidus temperature and liquidus temperature coincide, wherein the solidus temperature or eutectic point temperature of the second brazing material is lower than that of the first brazing material.

This configuration allows for the selection of alloy materials for the first and second brazing materials, thereby expanding the range of materials that can be used. Furthermore, by setting the solidus temperature or eutectic temperature of the second brazing material lower than that of the first brazing material, melting and deterioration of the first brazing material at the joint between the first refrigerant piping and the equipment body during brazing of the first and second refrigerant piping can be effectively suppressed.

Furthermore, it is even more preferable that the second brazing material is an alloy material having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature, and that the liquidus temperature of the second brazing material is lower than the solidus temperature or eutectic temperature of the first brazing material.

With this configuration, even when brazing is performed at a temperature exceeding the liquidus temperature of the second brazing material from the perspective of brazing flowability, the liquidus temperature of the second brazing material is lower than the solidus temperature or eutectic temperature of the first brazing material. Therefore, melting or alteration of the first brazing material can be effectively suppressed.

Furthermore, in the above configuration where the melting point of the second brazing material is lower than that of the first brazing material, it is preferable that the second brazing material contains copper and at least one of silver and phosphorus.

This configuration allows the melting point of the second brazing material to be effectively set lower than that of the first brazing material.

Furthermore, it is preferable that the plating layer at the other end of the first refrigerant pipe extends beyond the insertion length into which the second refrigerant pipe is inserted or inserted, towards the one end.

This configuration allows for the reliable formation of a fillet in the brazed joint between the first and second refrigerant pipes, without creating gaps between the inserted pipes where no brazing material is present. This prevents crevice corrosion after brazing, resulting in a refrigerant pipe joint with excellent corrosion resistance.

Furthermore, the valve device is a valve device as a refrigerant device as described above, characterized in that the device body comprises a valve body with a valve chamber formed inside and to which the refrigerant piping is connected, and the valve body is made of stainless steel.

According to this valve device, since the aforementioned refrigerant equipment is used as the valve device, stainless steel refrigerant piping can be brazed to the equipment body and other piping while minimizing the workload.

Furthermore, the refrigeration cycle system of the present invention is characterized by comprising the above-described equipment piping connection structure.

This refrigeration cycle system, equipped with the aforementioned equipment piping connection structure, allows for brazing and joining of stainless steel refrigerant piping to the equipment body and other piping, minimizing the workload involved.

According to the equipment piping connection structure and refrigeration cycle system of the present invention, stainless steel refrigerant piping can be brazed to the equipment body and other piping while minimizing the workload.

This is a partial cross-sectional view showing an electric valve, which is a first embodiment of a refrigerant device and valve system. Figure 1 is a schematic diagram showing a refrigeration cycle system equipped with an electric valve. Figure 1 is a schematic diagram showing how the side refrigerant piping is connected to the valve body. This figure shows the refrigerant equipment of the second embodiment in a schematic diagram equivalent to that of Figure 3. This figure shows a refrigerant device of the third embodiment, using a schematic diagram similar to that of Figure 3. This figure shows a refrigerant device of the fourth embodiment, using a schematic diagram similar to that of Figure 5. This figure shows a refrigerant device of the fifth embodiment, using a schematic diagram similar to that of Figure 3.

The following describes a first embodiment of the refrigerant equipment, equipment piping connection structure, valve device, and refrigeration cycle system based on Figures 1 to 3.

Figure 1 is a partial cross-sectional view showing an electric valve, which is a first embodiment of the refrigerant equipment and valve system, and Figure 2 is a schematic diagram showing a refrigeration cycle system equipped with the electric valve shown in Figure 1.

The electric valve 10 of this embodiment is used as an expansion valve 100, described later, in the refrigeration cycle system 1 shown in Figure 2. This electric valve 10 comprises a device body 11, a bottom refrigerant pipe 12, and a side refrigerant pipe 13. The electric valve 10 is a valve device that adjusts the flow rate of refrigerant flowing between the bottom refrigerant pipe 12 and the side refrigerant pipe 13 via the valve chamber 11a by moving the valve body 11b in the valve chamber 11a back and forth relative to the valve seat member 11c using a motor drive. The device body 11 comprises a valve body 111-1 with a valve chamber 11a formed inside, and a case 111-2 that incorporates a mechanism for moving the valve body 11b back and forth. The case 111-2 is welded to the valve body 111-1 to form a housing 111 of the device body 11 having a cylindrical shape with both ends closed. The bottom refrigerant pipe 12 is a cylindrical pipe joined at one end by brazing to the bottom wall portion 111a of the valve chamber 11a in the valve body 111-1 of the equipment body 11, extending along the axis X. The side refrigerant pipe 13 is a cylindrical pipe joined at one end by brazing to the peripheral wall portion 111b of the valve chamber 11a in the valve body 111-1, extending perpendicular to the axis X. In this embodiment, the valve body 111-1 to which the bottom refrigerant pipe 12 and the side refrigerant pipe 13 are joined is made of stainless steel. The bottom refrigerant pipe 12 and the side refrigerant pipe 13 are also made of stainless steel.

As shown in Figure 1, a bottom wall through-hole 111c is formed in the bottom wall portion 111a of the valve chamber 11a in the valve body 111-1, which communicates with the bottom refrigerant piping 12. From the outer circumference of this bottom wall through-hole 111c, a pipe receiving cylinder 111d protrudes toward the outside of the valve chamber 11a to receive one end of the bottom refrigerant piping 12. The valve seat member 11c of the electric valve 10 is inserted into the bottom wall through-hole 111c and fixed in place by brazing or the like. One end of the bottom refrigerant piping 12 is inserted into this pipe receiving cylinder 111d and is brazed and fixed in a state that it can communicate with the valve chamber 11a via the valve seat member 11c in the bottom wall through-hole 111c. In addition, a circumferential wall through-hole 111g is formed in the circumferential wall portion 111b of the valve chamber 11a, through which the end of the side refrigerant piping 13 passes. The side refrigerant pipe 13 is brazed and fixed in place with one end inserted into the peripheral wall penetration hole 111g.

Next, the refrigeration cycle system 1, which uses the electric valve 10 as an expansion valve 100 to circulate the refrigerant, will be described in detail with reference to Figure 2. The refrigeration cycle system 1 of this embodiment comprises an expansion valve 100, an outdoor heat exchanger 200, an indoor heat exchanger 300, a flow path switching valve 400, and a compressor 500, all connected by conduits as shown in the figure, forming a heat pump type refrigeration cycle. Note that the accumulator, pressure sensor, temperature sensor, etc., are not shown in the figure.

The flow path of the refrigeration cycle is switched between two paths by the flow path switching valve 400: one for cooling operation and one for heating operation. During cooling operation, as shown by the solid arrows in Figure 2, the refrigerant compressed by the compressor 500 flows from the flow path switching valve 400 into the outdoor heat exchanger 200. This outdoor heat exchanger 200 functions as a condenser, and the liquid refrigerant discharged from the outdoor heat exchanger 200 flows through the expansion valve 100 into the indoor heat exchanger 300, which functions as an evaporator.

On the other hand, during heating operation, as shown by the dashed arrows in Figure 2, the refrigerant compressed by the compressor 500 is circulated in the following order: through the flow path switching valve 400, through the indoor heat exchanger 300, through the expansion valve 100, through the outdoor heat exchanger 200, through the flow path switching valve 400, and back to the compressor 500. The indoor heat exchanger 300 functions as a condenser, and the outdoor heat exchanger 200 functions as an evaporator. The expansion valve 100 depressurizes and expands the liquid refrigerant flowing in from the outdoor heat exchanger 200 during cooling operation, or from the indoor heat exchanger 300 during heating operation, and further controls the flow rate of the refrigerant. In Figure 2, the expansion valve 100 is provided so that liquid refrigerant from the outdoor heat exchanger 200 flows into the second joint pipe 102 (side refrigerant piping 13) during cooling operation, and liquid refrigerant from the indoor heat exchanger 300 flows into the first joint pipe 101 (bottom refrigerant piping 12) during heating operation. However, the system is not limited to this configuration; the expansion valve 100 may also be provided so that liquid refrigerant from the outdoor heat exchanger 200 flows into the first joint pipe 101 during cooling operation, and liquid refrigerant from the indoor heat exchanger 300 flows into the second joint pipe 102 during heating operation.

Next, regarding the bottom refrigerant piping 12 and the side refrigerant piping 13 connected to the stainless steel valve body 111-1 of the equipment body 11 of the electric valve 10 shown in Figure 1, we will explain using the side refrigerant piping 13 as a representative example.

Figure 3 is a schematic diagram showing the valve body shown in Figure 1 with the side refrigerant piping connected. Note that in Figure 3, only the component corresponding to the valve body 111-1 and the component corresponding to the side refrigerant piping 13 in Figure 1 are shown. However, in the following description, the component comprising these two parts will be referred to as the refrigerant equipment 10a. Also, in Figure 3, only the pipe connection portion of the component corresponding to the valve body 111-1 in Figure 1 is shown in a cross-sectional view; the other parts are simplified. Hereafter, this component will be referred to as the equipment body 15. Furthermore, the component corresponding to the side refrigerant piping 13 will simply be referred to as the refrigerant piping 16. Note that the structure of the refrigerant piping 16 described below is also applicable to the bottom refrigerant piping 12 shown in Figure 1; therefore, its illustration and redundant explanation in Figure 3 will be omitted.

In the refrigeration equipment 10a shown in Figure 3, both the equipment body 15 and the refrigerant piping 16 are made of stainless steel, and the equipment body 15 and one end 161 of the refrigerant piping 16 are brazed together with brazing material 17. Furthermore, a plating layer 18 is provided on the outer surface 163a of a predetermined range 163 including the other end 162 of the refrigerant piping 16. This predetermined range 163, where the plating layer 18 is formed, is the area where other refrigerant piping and other components are joined by brazing.

In this embodiment, the melting point of the brazing material 17 is lower than the melting point of the plating layer 18. In this case, the plating layer 18 is formed by plating of a single metal having a single melting point; specifically, it is formed by plating mainly composed of copper. This copper-based plating layer 18 is intended for use as a brazing joint, for example, copper piping or piping with copper plating applied to the joint, and its melting point is 1085°C. Note that the single-metal plating (copper-based plating layer 18) may contain not only the main metal element forming the plating layer but also other elements resulting from the plating bath.

On the other hand, the brazing material 17 is a metallic material containing two or more metals, and is an alloy material having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature. This alloy brazing material 17 may be phosphor bronze brazing material, silver brazing material, or nickel brazing material. Table 1 below shows the solidus and liquidus temperatures for these brazing materials.

Table 1 shows the solidus and liquidus temperatures for phosphor bronze solder, silver solder, and Ni solder, as well as phosphor bronze solder, which is relatively inexpensive compared to other soldering materials. Although not illustrated in Table 1, soldering materials with eutectic temperatures where the solidus and liquidus temperatures coincide can also be used, depending on the amount of the main component and the amount of elements added to the main component.

Phosphorus copper brazing material is a brazing material primarily composed of copper with added phosphorus, or with added silver and phosphorus. The physical properties, such as solidus temperature and liquidus temperature, vary depending on the amount of silver and phosphorus added. Table 1 shows the solidus and liquidus temperatures for phosphorus copper brazing materials 1 through 5, each with different amounts of silver and phosphorus.

Phosphor bronze solder is a brazing material primarily composed of copper, with added phosphorus and tin. The physical properties, such as solidus temperature and liquidus temperature, vary depending on the amount of phosphorus and tin added. Table 1 shows the solidus and liquidus temperatures for two types of phosphorus bronze solder, the first and second types, with different amounts of phosphorus and tin added.

Silver solder is a soldering material primarily composed of copper and silver. Its physical properties, such as solidus temperature and liquidus temperature, vary depending on the copper content. Table 1 shows the solidus and liquidus temperatures for silver solders 1 through 7, each with different copper content.

Ni brazing material is a brazing material primarily composed of Ni and containing Cr. Its physical properties, such as solidus temperature and liquidus temperature, vary depending on the other additives. Table 1 shows the solidus and liquidus temperatures for three different types of Ni brazing materials (Types 1-3) with varying additives.

Here, the brazing material 17 is selected such that its solidus temperature is lower than the melting point (1085°C) of the copper-based plating layer 18. More precisely, the brazing material 17 is selected such that its liquidus temperature is lower than the melting point of the plating layer. In the brazing materials shown in Table 1, with the exception of the third Ni brazing material, all of them have both a solidus temperature and a liquidus temperature lower than the melting point of the plating layer, making them suitable for use as the brazing material 17 as described above. With such a brazing material 17, even if brazing is performed at a brazing temperature exceeding the liquidus temperature of the brazing material 17 from the perspective of the brazing properties of the molten brazing material 17, melting and alteration of the plating layer 18 can be effectively suppressed.

On the other hand, the third Ni brazing material has a solidus temperature (1080°C) lower than the melting point of the plating layer 18, and by strictly controlling the brazing temperature, melting or alteration of the plating layer 18 can be suppressed. However, since the difference between the solidus temperature of the third Ni brazing material and the melting point of the plating layer 18 is only 5°C, it is necessary to strictly control the temperature of the brazing atmosphere. Furthermore, for the third Ni brazing material, the liquidus temperature (1135°C) is higher than the melting point of the plating layer 18, so high-temperature brazing, as performed from the perspective of brazing flexibility mentioned above, should be avoided.

When phosphor bronze brazing material 17 is used, brazing by furnace brazing becomes possible. Furnace brazing is a method in which the entire refrigerant piping 16 and the equipment body 15, which are to be brazed, are placed in a furnace filled with a high-temperature atmosphere (for example, a hydrogen atmosphere) that can remove the oxide film on the stainless steel surface, and brazing is performed.

Next, two examples of modifications from the first embodiment described with reference to Figures 1 to 3, namely the second and third embodiments, will be described. In both of these embodiments, the position of the plating layer in the refrigerant piping differs from that of the first embodiment. The following descriptions of the two embodiments will focus on the differences from the first embodiment. On the other hand, the electric valves and refrigeration cycle systems, which are equivalent to those in the first embodiment, will not be described.

Figure 4 shows the refrigeration equipment of the second embodiment in a schematic diagram equivalent to that of Figure 3. Note that in Figure 4, components equivalent to those shown in Figure 3 are denoted by the same reference numerals as in Figure 3, and therefore, redundant explanations of these equivalent components will be omitted below.

In the refrigerant equipment 20a shown in Figure 4, the refrigerant piping 16, with one end 161 brazed to the equipment body 15 using brazing material 17, has a plating layer 28 on the other end 162 side, provided on the inner circumferential surface 263a of a predetermined range 163 including the other end 162. Except for the fact that the plating layer 28 is provided on the inner circumferential surface 263a, the difference in melting point between the plating layer 28 and the brazing material 17, and the material of the plating forming the plating layer 28 are the same as in the first embodiment.

Figure 5 shows the refrigeration equipment of the third embodiment in a schematic diagram equivalent to that of Figure 3. Note that in Figure 5, components equivalent to those shown in Figure 3 are given the same reference numerals as in Figure 3, and therefore, redundant explanations of these equivalent components will be omitted below.

In the refrigerant equipment 30a shown in Figure 5, in the refrigerant pipe 16, one end 161 is brazed to the equipment body 15 with a brazing material 17, and the plating layer 38 on the other end 162 side is provided in the following positions within a predetermined range 163 that includes the other end 162. That is, the plating layer 38 is provided over the inner circumferential surface 363a, the opening edge 363b, and the outer circumferential surface 363c within the above predetermined range 163. Except for the fact that the plating layer 38 is provided over the inner circumferential surface 363a to the outer circumferential surface 363c, the difference in melting point between the plating layer 38 and the brazing material 17, and the material of the plating that forms the plating layer 38 are the same as in the first embodiment. Since the plating layer 38 is formed on both the inner circumferential surface 363a and the outer circumferential surface 363c, another refrigerant pipe made of copper or copper-plated can be attached and brazed to the other end 162 of the refrigerant pipe 16 in either an internal or external insertion form. Furthermore, because the plating layer 38 is also formed on the open end edge 363b, a good fillet is formed during brazing on both the open end edge side of the other refrigerant pipe attached to the other end 162 and the open end edge 363b side of this refrigerant pipe 16. That is, the portion of the open end edge 363b of the refrigerant pipe 16 is also made of copper due to the plating layer 38, and since it has the same surface characteristics as other refrigerant pipes made of copper or copper-plated, a good fillet can be formed.

The refrigerant equipment 10a, 20a, 30a, electric valve 10, and refrigeration cycle system 1 of the first to third embodiments described above can provide the following effects. Specifically, according to the first to third embodiments, by appropriately selecting the material of the plating layers 18, 28, and 38 on the other end 162 side of the stainless steel refrigerant piping 16 to match the material of other pipes, etc., the workload can be reduced and brazing can be performed to join with other pipes, etc. In this case, according to the first to third embodiments, the melting point of the brazing material 17 used for brazing one end 161 of the refrigerant piping 16 to the equipment body 15 is lower than the melting point of the plating layers 18, 28, and 38. Therefore, the heat generated during brazing of one end 161 of the refrigerant piping 16 to the equipment body 15 prevents the plating layers 18, 28, and 38 on the other end 162 side from melting or degrading. Consequently, there is almost no concern about the impact on the plating layers 18, 28, and 38 when brazing one end 161 of the refrigerant piping 16 to the equipment body 15. According to the first to third embodiments, anticipating this point, a method such as furnace brazing, which reduces the workload, can be employed to hermetically join the equipment body 15 and the stainless steel refrigerant piping 16. Furnace brazing requires less workload than methods such as burner (torch) brazing, which involves manually brazing while applying flux to remove the oxide film. Thus, according to the first to third embodiments, the stainless steel refrigerant piping 16 can be brazed to the equipment body 15 and other piping while minimizing the workload.

In the first to third embodiments, the brazing material 17 is an alloy material having two melting points: a solidus temperature and a liquidus temperature, while the plating layer 18 is formed by plating of a single metal having a single melting point. Furthermore, the brazing material 17 is selected such that its solidus temperature is lower than the melting point of the plating layer 18. Firstly, by using an alloy material for the brazing material 17, the range of selection for the brazing material 17 can be expanded. Moreover, with the above configuration, by setting the solidus temperature of the brazing material 17 lower than the melting point of the plating layer 18, melting and deterioration of the plating layer 18 at the other end 163 of the refrigerant piping 16 can be effectively suppressed during brazing of one end 161 of the refrigerant piping 16 to the equipment body 15.

Furthermore, in the first to third embodiments, the brazing material 17 is selected in which its liquidus temperature is lower than the melting point of the plating layer 18. With this configuration, even when brazing is performed at high temperatures as described above from the viewpoint of brazing flowability, the liquidus temperature of the brazing material 17 is lower than the melting point of the plating layer 18, so melting and deterioration of the plating layer 18 can be effectively suppressed.

Furthermore, in the first to third embodiments, the plating layers 18, 28, and 38 are formed with a copper-based plating. This configuration allows for good brazing to copper pipes or copper-plated pipes, which are often assumed to be the joining destination for the other end 162 of the refrigerant pipe 16. On the other hand, the brazing material 17 may be phosphor bronze brazing material with copper as the main component, or silver brazing material with copper and silver as the main components, or Ni brazing material. This configuration allows for effectively setting the melting point of the brazing material 17 lower than the melting points of the plating layers 18, 28, and 38. Therefore, when brazing one end 161 of the refrigerant pipe 16 to the equipment body 15, melting or deterioration of the plating layers 18, 28, and 38 at the other end 62 can be effectively avoided.

This concludes the explanation of the first to third embodiments. Next, we will explain the fourth and fifth embodiments. Both the fourth and fifth embodiments relate to the equipment piping connection structure using the third embodiment described above, and involve brazing other piping to the other end of a stainless steel refrigerant pipe, one end of which is brazed to the equipment body. The following explanation of the fourth and fifth embodiments will focus on the differences from the third embodiment. On the other hand, electric valves and refrigeration cycle systems, which are equivalent to the third embodiment (i.e., equivalent to the first embodiment), will not be explained. Furthermore, in the following, the refrigerant piping on the equipment body side will be referred to as the first refrigerant piping, and the other piping brazed to this first refrigerant piping will be referred to as the second refrigerant piping. Also, the brazing material used for brazing the equipment body and the first refrigerant piping will be referred to as the first brazing material, and the brazing material used for brazing the first refrigerant piping and the second refrigerant piping will be referred to as the second brazing material.

Figure 6 shows the equipment piping connection structure of the fourth embodiment, using a schematic diagram similar to that of Figure 5. Note that in Figure 6, components equivalent to those shown in Figure 5 are denoted by the same reference numerals as in Figure 5; therefore, redundant explanations of these equivalent components will be omitted below.

In the equipment piping connection structure 40a shown in Figure 6, one end 161 of the first refrigerant pipe 46-1 is brazed to the equipment body 15 of the refrigerant equipment 40b using a first brazing material 47-1. A plating layer 38 is formed over a predetermined range 163 including the other end 162 of the first refrigerant pipe 46-1, extending to the inner circumferential surface 363a, the opening edge 363b, and the outer circumferential surface 363c. The end of the second refrigerant pipe 46-2 is then fitted onto the other end 162 of the first refrigerant pipe 46-1 and brazed to it using a second brazing material 47-2. The opposing surface 464 of the second refrigerant pipe 46-2, which faces the outer circumferential surface of the first refrigerant pipe 46-1, is made of the same material or a similar material as the plating layer 38. Specifically, the plating layer 38 is formed of a plating primarily composed of copper, and the second refrigerant pipe 46-2, including the opposing surface 464, is a copper pipe formed of a metal primarily composed of copper.

In this embodiment, the length of the first refrigerant pipe 46-1 is greater than or equal to its outer diameter. Preferably, the length of the first refrigerant pipe 46-1 is such that the distance from the end face of the plating layer 38 on the equipment body 15 side to the outer surface of the equipment body 15 is greater than or equal to the outer diameter of the first refrigerant pipe 46-1. By setting the length of the first refrigerant pipe 46-1 in this way, the influence of the heat generated during brazing of the second refrigerant pipe 46-2 on the brazed portion of the first refrigerant pipe 46-1 can be further reduced. This effect can be more reliably obtained if the distance from the end face of the plating layer 38 on the equipment body 15 side to the outer surface of the equipment body 15 is at least twice the length of the plating layer 38.

Furthermore, although the first refrigerant pipe 46-1 and the second refrigerant pipe 46-2 are shown as straight pipes in this embodiment, these pipes may be bent. That is, the first refrigerant pipe 46-1 and the second refrigerant pipe 46-2 may be bent as appropriate according to the layout of the piping attached to the refrigerant equipment 40b.

Furthermore, in this embodiment, both the first brazing material 47-1 and the second brazing material 47-2 are made of the alloy material described above. The brazing materials are selected from those shown in Table 1 above such that the melting point of the second brazing material 47-2 is lower than that of the first brazing material 47-1; specifically, the solidus temperature of the second brazing material 47-2 is lower than that of the first brazing material 47-1. More precisely, the selection is made so that the liquidus temperature of the second brazing material 47-2 is lower than that of the first brazing material.

For the first brazing material 47-1, either the first or second phosphor bronze brazing material is used. These phosphor bronze brazing materials are less expensive than Ni brazing material and have relatively high melting points (solidus temperature and liquidus temperature), making them less susceptible to the effects of heating during brazing with the second brazing material 47-2.

As the second brazing material 47-2, one of the first to fifth phosphor bronze brazing materials is used. These phosphor bronze brazing materials are primarily composed of inexpensive copper, and their solidus and liquidus temperatures are relatively low. Depending on the combination of the first and second phosphor bronze brazing materials 47-1 and the first to fifth phosphor bronze brazing materials 47-2, the solidus temperature of the first brazing material 47-1 can be set nearly 100°C higher than the liquidus temperature of the second brazing material 47-2. This allows for minimizing the effects of overheating even if the second brazing material 47-2 is locally overheated during brazing, provided that the first brazing material 47-1 is phosphor bronze brazing material.

Furthermore, in this embodiment, the plating layer 38 at the other end 162 of the first refrigerant pipe 46-1 extends beyond the insertion length L41 into which the second refrigerant pipe 46-2 is externally fitted, towards the one end 161.

Figure 7 shows the equipment piping connection structure of the fifth embodiment, using a schematic diagram similar to that of Figure 3. Note that in Figure 7, components equivalent to those shown in Figure 3 are denoted by the same reference numerals as in Figure 3; therefore, redundant explanations of these equivalent components will be omitted below.

In the equipment piping connection structure 50a shown in Figure 7, a first plating layer 58-1 equivalent to the plating layer 38 of the third embodiment is formed on the other end 162 side of the first refrigerant pipe 46-1, whose one end 161 is brazed to the equipment body 15 of the refrigerant equipment 50b using a first brazing material 47-1. In this embodiment, the second refrigerant pipe 56-2, which is externally mounted on the other end 162 side of the first refrigerant pipe 46-1, is made of stainless steel. A second plating layer 58-2, formed of the same material or a similar material as the first plating layer 58-1, is provided on the inner circumferential surface of the second refrigerant pipe 56-2, including the surface 564 facing the outer circumferential surface of the first refrigerant pipe 46-1. In other words, in this embodiment, the second plating layer 58-2 is formed on the stainless steel second refrigerant pipe 56-2 with a copper-based plating of the same material or a similar material as the first plating layer 58-1. Furthermore, in this embodiment as well, the second brazing material 57-2 is the same as that used in the fourth embodiment described above, and its melting point is lower than that of the first brazing material 47-1.

It goes without saying that the equipment piping connection structures 40a, 50a, the electric valve 10, and the refrigeration cycle system 1 of the fourth and fifth embodiments described above also achieve the same effects as those of the first to third embodiments. That is, even with the fourth and fifth embodiments, the stainless steel refrigerant piping 16 can be brazed to the equipment body 15 and other piping while minimizing the workload.

Furthermore, in the fourth and fifth embodiments, the second refrigerant pipes 46-2 and 5 are connected to the first refrigerant pipe 46-1.
6-2 is extrapolated and joined. The opposing surfaces 464, 564 of the second refrigerant pipes 46-2, 56-2 with respect to the first refrigerant pipe 46-1 are formed of the same material or a similar material as the plating layer 38 or first plating layer 58-1 of the first refrigerant pipe 46-1. With this configuration, the first refrigerant pipe 46-1 and the second refrigerant pipes 46-2, 56-2 can be brazed together with metals of the same material or a similar material facing each other, thus further reducing the workload for brazing the two.

Furthermore, in the fourth embodiment, the second refrigerant pipe 46-2 is formed of the same material or a similar metal as the plating layer 38 of the first refrigerant pipe 46-1. This configuration allows the plating layer 38 of the first refrigerant pipe 46-1 and the opposing surface 464 of the second refrigerant pipe 46-2 to be effectively made of the same material or a similar material.

Furthermore, in the fourth embodiment, the plating layer 38 on the first refrigerant pipe 46-1 is provided to extend beyond the insertion length L41 of the second refrigerant pipe 46-2. With this configuration, during brazing of the first refrigerant pipe 46-1 and the second refrigerant pipe 46-2, a fillet can be reliably formed at the brazed joint without creating a gap between the inserted pipes where no brazing material exists. This prevents crevice corrosion after brazing, resulting in a refrigerant pipe joint with excellent corrosion resistance.

Furthermore, in the fifth embodiment, a second plating layer 58-2, formed from the same or a similar material as the first plating layer 58-1, is provided in the area of the second refrigerant pipe 56-2 including the surface 564 facing the first refrigerant pipe 46-1. This configuration also effectively ensures that the first plating layer 58-1 of the first refrigerant pipe 46-1 and the facing surface 564 of the second refrigerant pipe 56-2 are made of the same or a similar material. Moreover, this configuration increases the degree of freedom in selecting the material of the second refrigerant pipe 56-2.

Furthermore, in the fifth embodiment, given the increased freedom in selecting the material of the second refrigerant pipe 56-2, stainless steel piping is used for the second refrigerant pipe 56-2. This configuration allows for cost reduction by using inexpensive stainless steel piping for the second refrigerant pipe 56-2, while maintaining the same or similar material for the first plating layer 58-1 and the opposing surface 564 of the second refrigerant pipe 56-2.

Furthermore, in the fourth and fifth embodiments, the melting point of the second brazing material 47-2 and 57-2 used to braze the first refrigerant pipe 46-1 to the second refrigerant pipes 46-2 and 56-2 is lower than the melting point of the first brazing material 47-1 used to braze the first refrigerant pipe 46-1 to the equipment body 15. This configuration effectively suppresses the melting and deterioration of the first brazing material 47-1 at the joint between the first refrigerant pipe 46-1 and the equipment body 15 due to the heat generated during brazing of the first refrigerant pipe 46-1 to the second refrigerant pipes 46-2 and 56-2.

Furthermore, in the fourth and fifth embodiments, both the first brazing material 47-1 and the second brazing material 47-2 are alloy materials, and the solidus temperature of the second brazing material 47-2 is lower than that of the first brazing material 47-1. This configuration allows for a broader selection range of brazing materials by employing alloy materials for both the first brazing material 47-1 and the second brazing material 47-2. Moreover, due to the aforementioned relationship between the solidus temperatures, melting and deterioration of the first brazing material 47-1 at the joint between the first refrigerant pipe 46-1 and the equipment body 15 during brazing of the first refrigerant pipe 46-1 and the second refrigerant pipe 46-2 can be effectively suppressed.

Furthermore, in the fourth and fifth embodiments, the liquidus temperature of the second brazing material 47-2 is lower than the solidus temperature of the first brazing material 47-1. With this configuration, even when brazing is performed at a temperature exceeding the liquidus temperature of the second brazing material 47-2 from the viewpoint of brazing flowability, the melting and deterioration of the first brazing material 47-1 can be effectively suppressed due to the above-mentioned relationship between the liquidus temperature and the solidus temperature.

Furthermore, in the fourth and fifth embodiments, the second brazing materials 47-2 and 57-2 are used, which contain copper and at least one of silver and phosphorus. This configuration allows the melting points of the second brazing materials 47-2 and 57-2 to be effectively set lower than those of the first brazing material 47-1.

Furthermore, the first to fifth embodiments described above merely represent typical forms of the present invention, and the present invention is not limited thereto. That is, it can be implemented with various modifications without departing from the core principles of the present invention. Even with such modifications, as long as the refrigerant equipment, equipment piping connection structure, valve device, and refrigeration cycle system configuration of the present invention are still present, they are of course included within the scope of the present invention.

For example, in the first to fifth embodiments described above, an electric valve 10 used as an expansion valve 100 in the refrigeration cycle system 1 is exemplified as an example of refrigerant equipment and valve devices. However, the refrigerant equipment and valve devices are not limited to this. Regarding the valve device, it is not limited to an electric valve as an expansion valve; it may also be various valve devices other than electric valves, such as solenoid valves or manual valves, or various valve devices other than expansion valves, such as flow path switching valves, check valves, and shut-off valves. Furthermore, the refrigerant equipment is not limited to valve devices; it may also be various devices such as acculators, oil separators, and compressors.

Furthermore, in the first to fifth embodiments described above, an example of a refrigerant device and valve system is provided: an electric valve 10 equipped with two connecting pipes, a bottom refrigerant pipe 12 and a side refrigerant pipe 13, where the structure relating to the side refrigerant pipe 13 is also applied to the bottom refrigerant pipe 12. However, the refrigerant device and valve system are not limited to this. The number of refrigerant pipes, such as connecting pipes, can be set to any number, and the brazing and plating layer structures of the refrigerant pipes described above may be applied to only some of the refrigerant pipes.

Furthermore, in the first to fifth embodiments described above, examples of refrigerant equipment include refrigerant equipment 10, 10a, 20a, 30a, 40b, and 50b in which the brazing material 17 and the first brazing material 47-1 are alloy materials having two melting points, a solidus temperature and a liquidus temperature. However, refrigerant equipment and equipment piping connection structures are not limited to these, and alloy materials having a eutectic temperature at which the solidus temperature and liquidus temperature coincide may be used as the brazing material on the equipment body side and the first brazing material. Also, in the fourth and fifth embodiments described above, examples of equipment piping connection structures include equipment piping connection structures 40a and 50a in which the first brazing material 47-1 and the second brazing materials 47-2 and 57-2 are all alloy materials having two melting points, a solidus temperature and a liquidus temperature. However, the equipment piping connection structure is not limited to these; at least one of the first and second brazing materials may be an alloy material having a melting point at its eutectic temperature.

Furthermore, in the first to fifth embodiments described above, examples of refrigerant equipment include refrigerant equipment 10, 10a, 20a, 30a, 40b, and 50b, in which the brazing material 17 and the first brazing material 47-1 are alloy materials, and the plating layers 18, 28, 38 and the first plating layer 58-1 are formed by plating of a single metal. In this example, the solidus temperature of the brazing material 17 and the first brazing material 47-1 is lower than the melting point of the plating layers 18, 28, 38 and the first plating layer 58-1. However, refrigerant equipment is not limited to these examples, and the specific types of brazing materials and plating layers can be set as appropriate. As long as the melting point of the brazing material is lower than the melting point of the plating layer, the specific type of melting point, such as the solidus temperature, is not relevant. However, as mentioned above, using alloy materials for the brazing material 17 and the first brazing material 47-1 expands the range of brazing material options. Furthermore, as mentioned above, by lowering the solidus temperature of the brazing material 17 and the first brazing material 47-1 to the melting point of the plating layers 18, 28, 38 and the first plating layer 58-1, melting and deterioration of the plating layer can be effectively suppressed during brazing of the equipment body. In addition, alloy materials having the above-mentioned eutectic temperature as their melting point may be used as the brazing material and the first brazing material, but in this case, it is even more preferable that their eutectic temperature is lower than the melting point of the plating layer and the first plating layer.

Furthermore, in the first to fifth embodiments described above, examples of refrigerant equipment are provided, specifically refrigerant equipment 10, 10a, ..., 50a, in which the liquidus temperatures of the brazing material 17 and the first brazing material 47-1 are lower than the melting points of the plating layers 18, 28, 38 and the first plating layer 58-1. However, refrigerant equipment is not limited to these examples, and the specific type of melting point of the brazing material is not relevant as long as it is lower than the melting point of the plating layer. However, as mentioned above, lowering the liquidus temperatures of the brazing material 17 and the first brazing material 47-1 below the melting points of the plating layers 18, 28, 38 and the first plating layer 58-1 effectively suppresses melting and deterioration of the plating layer during brazing of the equipment body.

Furthermore, in the first to fifth embodiments described above, plating layers 18, 28, 38 and the first plating layer 58-1, formed with copper as the main component, are exemplified as examples of plating layers formed on the refrigerant piping on the equipment body side. However, the plating layers formed on the refrigerant piping on the equipment body side are not limited to these and can be arbitrarily selected according to the material of the expected joining destination. However, as mentioned above, plating layers 18, 28, 38 and the first plating layer 58-1, formed with copper as the main component, allow for good brazing joints with copper piping or copper-plated piping, which are often expected to be used as joining destinations.

Furthermore, in the fourth and fifth embodiments described above, as an example of an equipment piping connection structure, equipment piping connection structures 40a and 50a are exemplified in which the ends of the second refrigerant pipes 46-2 and 56-2 are externally fitted and joined to the other end 162 of the first refrigerant pipe 46-1. However, the equipment piping connection structure is not limited to this, and the end of the second refrigerant pipe may be internally fitted to the other end of the first refrigerant pipe.

Furthermore, in the fourth and fifth embodiments described above, as an example of an equipment piping connection structure, equipment piping connection structures 40a and 50a are exemplified in which the opposing surfaces 464 and 564 of the second refrigerant pipes 46-2 and 56-2 to the first refrigerant pipe 46-1 are formed as follows. That is, in these equipment piping connection structures 40a and 50a, the opposing surfaces 464 and 564 of the second refrigerant pipes 46-2 and 56-2 are formed of the same material or a similar material as the plating layer 38 or first plating layer 58-1 of the first refrigerant pipe 46-1. However, the refrigerant equipment is not limited to this, and the opposing surfaces of the second refrigerant pipes may be formed of a different material or a different material from the plating layer of the first refrigerant pipe. However, as described above, by using the same material or a similar material for both, the brazing of the first refrigerant pipe 46-1 and the second refrigerant pipes 46-2 and 56-2 can be performed with even less work burden.

Furthermore, in the fourth and fifth embodiments described above, the following second refrigerant pipes 46-2 and 56-2 are provided as examples of second refrigerant pipes in which the opposing surface is formed of a metal of the same material or a similar material as the plating layer of the first refrigerant pipe. Specifically, the second refrigerant pipe 46-2 of the fourth embodiment is formed of a metal of the same material or a similar material as the plating layer 38 of the first refrigerant pipe 46-1. In the fifth embodiment, the second refrigerant pipe 56-2 is provided with a second plating layer 58-2 formed of a plating of the same material or a similar material as the first plating layer 58-1 on at least the surface 564 facing the first refrigerant pipe 46-1. Moreover, the second refrigerant pipe 56-2 of this fifth embodiment is made of stainless steel. However, the second refrigerant pipe is not limited to these, and the pipe material, plating layer material, etc. can be set as appropriate. However, as described above, the second refrigerant pipes 46-2 and 56-2 allow for the effective use of the same material or a similar material for the opposing surfaces 464 and 564 of the plating layer 38 and the first plating layer 58-1 and the second refrigerant pipes 46-2 and 56-2. Furthermore, as described above, costs can be reduced by providing the second plating layer 58-2 while making the second refrigerant pipe 56-2 out of stainless steel.

Furthermore, in the fourth and fifth embodiments described above, as an example of a second brazing material for brazing the second refrigerant pipe to the first refrigerant pipe, second brazing materials 47-2 and 57-2 are exemplified, having a lower melting point than the first brazing material 47-1 used to braze the first refrigerant pipe 46-1 to the equipment body 15. However, the second brazing material is not limited to these, and its melting point and other properties can be arbitrarily set. However, as mentioned above, using second brazing materials 47-2 and 57-2 with a lower melting point than the first brazing material 47-1 effectively suppresses the melting and deterioration of the first brazing material caused by the heat generated during brazing the two refrigerant pipes.

Furthermore, in the fourth and fifth embodiments described above, examples of the first and second brazing materials are given, both being alloy materials, with the latter having a solidus temperature lower than the former. These examples include the first brazing material 47-1 and the second brazing materials 47-2, 57-2. However, the first and second brazing materials are not limited to these, and may both be single metals, with the single melting point of the second brazing material being lower than the single melting point of the first brazing material. However, as mentioned above, using alloy materials broadens the range of brazing material options, and by lowering the solidus temperature of the second brazing material to that of the first brazing material, melting or alteration of the first brazing material during brazing with the second brazing material can be effectively suppressed. It should also be noted that at least one of the first and second brazing materials may be an alloy material having the above-mentioned eutectic temperature as its melting point. When using an alloy material having a eutectic temperature as the first brazing material and an alloy material having both a solidus temperature and a liquidus temperature as the second brazing material, it is preferable to lower the solidus temperature of the second brazing material than the eutectic temperature of the first brazing material. Conversely, when using an alloy material having both a solidus temperature and a liquidus temperature as the first brazing material and an alloy material having a eutectic temperature as the second brazing material, it is preferable to lower the eutectic temperature of the second brazing material than the solidus temperature of the first brazing material. When using alloy materials having a eutectic temperature for both the first and second brazing materials, it is preferable to lower the eutectic temperature of the second brazing material than the eutectic temperature of the first brazing material.

Furthermore, in the fourth and fifth embodiments described above, as examples of the first and second brazing materials, a first brazing material 47-1 and second brazing materials 47-2, 57-2 are provided, in which the liquidus temperature of the latter is lower than the solidus temperature of the former. However, the first and second brazing materials are not limited to these, and the specific type of melting point of each brazing material is not relevant, as long as the melting point of the second brazing material is lower than the melting point of the first brazing material. However, as described above, by making the liquidus temperature of the second brazing materials 47-2, 57-2 lower than the solidus temperature of the first brazing material 47-1, melting and deterioration of the first brazing material 47-1 can be effectively suppressed during brazing with the second brazing materials 47-2, 57-2. Furthermore, when using an alloy material with a eutectic point temperature as the first brazing material and an alloy material with both a solidus temperature and a liquidus temperature as the second brazing material, it is preferable to lower the liquidus temperature of the second brazing material than the eutectic point temperature of the first brazing material.

Furthermore, in the fourth and fifth embodiments described above, examples of the plating layer, first brazing material, and second brazing material include a plating layer 18 mainly composed of copper, a first brazing material 47-1 employing phosphor bronze brazing material, and second brazing materials 47-2 and 57-2 employing phosphor copper brazing material. However, the plating layer, first brazing material, and second brazing material are not limited to these, and can be appropriately selected depending on the materials of the equipment body and the first and second refrigerant piping, as well as the brazing conditions. However, as mentioned above, the combination of materials described above is preferable in terms of both the material cost of the brazing material and the suppression of the effects of overheating during brazing.

Furthermore, in the fourth and fifth embodiments described above, as an example of a second brazing material having a lower melting point than the first brazing material, second brazing materials 47-2 and 57-2 are given, which are mainly composed of copper with at least one of silver and phosphorus added. However, the second brazing material is not limited to these, and its material and other properties can be arbitrarily set. However, as mentioned above, the melting point of the second brazing materials 47-2 and 57-2 made of the above materials can be effectively set lower than the melting point of the first brazing material 47-1.

Furthermore, in the fourth and fifth embodiments described above, as an example of a plating layer at the other end of the first refrigerant piping, a plating layer 38 and a first plating layer 58-1 are provided extending beyond the insertion length L41 of the second refrigerant pipes 46-2 and 56-2 toward the equipment body 15. However, the plating layer at the other end of the first refrigerant piping is not limited to this, and its plating range can be set to any range. However, as mentioned above, using a plating layer 38 and a first plating layer 58-1 extending beyond the insertion length L41 of the second refrigerant pipes 46-2 and 56-2 allows for the joining of refrigerant piping with excellent corrosion resistance.

1 Refrigeration cycle system 10 Electric valves 10a, 20a, 30a, 40b, 50b Refrigerant equipment 11 Equipment body 11a Valve chamber 11b Valve body 11c Valve seat member 12 First refrigerant piping 13 Second refrigerant piping 15 Equipment body 16 Refrigerant piping 17 Brazing material 18, 28, 38 Plating layer 40a, 50a Equipment piping connection structure 46-1 First refrigerant piping 46-2, 56-2 Second refrigerant piping 47-1 First brazing material 47-2, 57-2 Second brazing material 58-1 First plating layer 58-2 Second plating layer 100 Expansion valve 101 First joint pipe 102 Second joint pipe 111 Housing 111-1 Valve body 111-2 Case 111a Bottom wall portion 111b Peripheral wall portion 111c Bottom wall through hole 111d Piping receiver 111g Peripheral wall through hole 161 One end portion 162 Other end portion 163 Predetermined range 163a, 363c Outer peripheral surface 200 Outdoor heat exchanger 263a, 363a Inner peripheral surface 300 Indoor heat exchanger 363b Opening edge 400 Flow path switching valve 464 Opposing surface 500 Compressor L41 Insertion length X Axis

Claims (11)

A piping connection structure for equipment equipped with refrigerant equipment that constitutes a refrigeration cycle for circulating refrigerant,
The aforementioned refrigerant equipment,
The main unit of the device,
The equipment comprises stainless steel refrigerant piping connected to the main body of the equipment,
The main body of the equipment and one end of the refrigerant piping are brazed together with brazing material.
A plating layer is provided on at least one of the inner and outer surfaces within a predetermined range including the other end of the refrigerant piping.
The melting point of the brazing material is lower than the melting point of the plating layer.
The refrigerant piping is the first refrigerant piping, and the end of the second refrigerant piping is inserted or inserted into the other end of the first refrigerant piping and joined together.
The opposing surface of the second refrigerant pipe that faces the inner or outer circumferential surface of the first refrigerant pipe is formed of a metal of the same material or a similar material as the plating layer.
The brazing material used to braze one end of the first refrigerant piping to the main body of the equipment is the first brazing material.
A device piping connection structure characterized in that the second refrigerant piping is brazed to the other end of the first refrigerant piping with a second brazing material, and the melting point of the second brazing material is lower than the melting point of the first brazing material. The brazing material is a metallic material containing two or more metals, and is an alloy material having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature, or an alloy material having a eutectic temperature where the solidus temperature and liquidus temperature coincide.
The aforementioned plating layer is formed by plating of a single metal having a single melting point.
The equipment piping connection structure according to claim 1, characterized in that the solidus temperature or eutectic temperature of the brazing material is lower than the melting point of the plating layer. The brazing material is an alloy material having two melting points: a solidus temperature and a liquidus temperature that is higher than the solidus temperature.
The equipment piping connection structure according to claim 2, characterized in that the liquidus temperature of the brazing material is lower than the melting point of the plating layer. The aforementioned plating layer is formed by a plating mainly composed of copper,
The equipment piping connection structure according to claim 1, characterized in that the brazing material is mainly composed of copper, or mainly composed of copper and silver. The equipment piping connection structure according to claim 1, characterized in that the second refrigerant piping is formed of a metal of the same material or a similar material as the plating layer. The aforementioned plating layer is a first plating layer, and at least the opposing surface of the second refrigerant pipe is provided with a second plating layer formed of the same material or a similar material as the first plating layer.
The equipment piping connection structure according to claim 1, characterized in that the second refrigerant piping is made of stainless steel. Both the first brazing material and the second brazing material are metallic materials containing two or more metals, and are alloy materials having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature, or alloy materials having a eutectic temperature where the solidus temperature and liquidus temperature coincide.
The equipment piping connection structure according to claim 1, characterized in that the solidus temperature or eutectic temperature of the second brazing material is lower than the solidus temperature or eutectic temperature of the first brazing material. The second brazing material is an alloy material having two melting points: a solidus temperature and a liquidus temperature higher than the solidus temperature.
The equipment piping connection structure according to claim 7, characterized in that the liquidus temperature of the second brazing material is lower than the solidus temperature or eutectic temperature of the first brazing material. The equipment piping connection structure according to claim 1, characterized in that the second brazing material comprises copper and at least one of silver and phosphorus. The equipment piping connection structure according to claim 1, characterized in that the plating layer at the other end of the first refrigerant piping extends toward the one end beyond the insertion length into which the second refrigerant piping is inserted or inserted. A refrigeration cycle system characterized by comprising the equipment piping connection structure described in any one of claims 1 to 10.