Valve devices and refrigeration cycle systems

Abstract

To provide a joint pipe which enables improvement of joint strength in a brazed portion between a stainless pipe and an aluminium pipe, and to provide a device and a refrigeration cycle system.SOLUTION: A joint pipe 14 is a pipe formed by joining a stainless pipe 141 and an aluminium pipe 142 in an axial direction D11. The stainless pipe 141 and the aluminium pipe 142 are brazed by a brazing material 143a and the brazing part 143 is formed between the stainless pipe 141 and the aluminium pipe 142. A joint surface between the stainless pipe 141 and the brazing part 143 is provided with a load receiving part 144 which receives a load weight F11 applied in the axial direction D11.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a joint pipe, a device, and a refrigeration cycle system that constitute a refrigeration cycle system such as an air conditioner.

Background Art

[0002] Conventionally, as a device constituting an air conditioner (refrigeration cycle system, refrigeration device), etc., a device in which a refrigerant discharge pipe and a suction pipe are connected to a device main body has been used as a refrigerant device (see, for example, Patent Document 1). And, as a pipe in such a device, a joint pipe in which two pipes are joined to each other may be used.

[0003] In recent years, due to the influence of rising material costs, etc., the constituent materials of the device main body and various pipes are changing from conventional copper to inexpensive stainless steel or aluminum. At this time, the device main body that requires a certain degree of strength may be made of stainless steel, and some pipes may be made of aluminum due to ease of processing, etc.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally speaking, brazing aluminum is difficult. Brazing with stainless steel, in particular, is often extremely difficult, and this difficulty can lead to unstable joint strength. At the joint surface between stainless steel and aluminum, an intermetallic compound is formed between the aluminum brazing material and the stainless steel. While the boundary between the aluminum brazing material and aluminum alloys, resulting in high joint strength, the intermetallic compound formed at the joint surface with stainless steel is hard and brittle, resulting in less adhesion to the stainless steel. The properties of this intermetallic compound at the joint surface with stainless steel are one of the causes of the difficulty of brazing and the instability of the joint strength. In the case of the above-mentioned joined piping, stainless steel piping is often used for the piping connected to the stainless steel equipment body, as high joint strength can be obtained by using stainless steel brazing material. On the other hand, aluminum piping, which is easy to process, is sometimes used for the piping on the equipment side, where it is expected to be installed via various piping routes to the refrigerant equipment. In such joined piping, the brazing joint between stainless steel piping and aluminum piping can be difficult and unstable in terms of joint strength, so high quality control is currently required to maintain joint strength.

[0006] The objective of this invention is to increase the joint strength at the brazed joint between stainless steel pipes and aluminum pipes. Valve device The objective is to provide a refrigeration cycle system. [Means for solving the problem]

[0007] The valve device of the present invention comprises a device body having a stainless steel valve body with a valve chamber formed inside, and a joining pipe formed by joining a stainless steel pipe and an aluminum pipe in the axial direction, wherein one end of the stainless steel pipe is connected to the valve body in the device body, the other end of the stainless steel pipe is connected to the aluminum pipe, the stainless steel pipe and the aluminum pipe are brazed together with brazing material, a brazing material portion is formed between the stainless steel pipe and the aluminum pipe, and the stainless steel pipe and the brazing material portion The stainless steel piping side joint surface Of the stainless steel side joint surface and the aluminum side joint surface, which is the joint surface on the aluminum pipe side of the aluminum pipe and the brazing material portion, only the stainless steel side joint surface is used. A load-receiving section is provided to receive the load in the axial direction. The load-receiving portion is formed by a load-receiving projection that protrudes from the stainless steel side joining surface toward the cylindrical outer surface of the aluminum side joining surface, the load-receiving projection faces the cylindrical outer surface of the aluminum side joining surface, and the load-receiving projection is provided embedded in the brazing material portion. It is characterized by the following: Furthermore, another valve device of the present invention is a valve device comprising a device body having a stainless steel valve body with a valve chamber formed inside, and a joining pipe in which a stainless steel pipe and an aluminum pipe are joined in the axial direction, wherein one end of the stainless steel pipe is connected to the valve body in the device body, and the other end of the stainless steel pipe is connected to the aluminum pipe, the stainless steel pipe and the aluminum pipe are brazed together with brazing material, a brazing material portion is formed between the stainless steel pipe and the aluminum pipe, and a load-receiving portion that receives the axial load is provided only on the stainless steel side joining surface, which is the joining surface between the stainless steel pipe and the brazing material portion on the stainless steel pipe side, and the joining surface between the aluminum pipe and the brazing material portion on the aluminum pipe side, the load-receiving portion is formed as a load-receiving recess that is recessed in a direction away from the cylindrical outer surface of the aluminum side joining surface from the stainless steel side joining surface, the load-receiving recess faces the cylindrical outer surface of the aluminum side joining surface, and the brazing material portion is provided by fitting into the load-receiving recess.

[0008] this Valve device According to this, the load-bearing portion provided at the joint surface between the stainless steel pipe and the brazing material can withstand shear loads (i.e., axial loads) that are prone to causing delamination of the intermetallic compound from the joint surface. Furthermore, by preventing the above-mentioned load from being directly applied to the intermetallic compound through this support, delamination of the intermetallic compound is suppressed, and thus the aluminum pipe can resist axial forces. In other words, the above Valve device According to this research, the joint strength of the brazed joint between stainless steel and aluminum pipes can be increased.

[0009] Here, the load bearing Concave The department is, Note Concave radially from the stainless steel side joint surface. and extending in a direction intersecting the radial direction It is preferable that the structure is composed of load-receiving grooves, and that the brazing material portion is fitted into the load-receiving grooves.

[0010] This configuration, with its simple structure of inserting brazing material into the load-receiving groove that constitutes the load-receiving section, effectively withstands axial loads and further suppresses delamination of intermetallic compounds.

[0011] Furthermore, it is preferable that the load-receiving grooves be arranged in a plurality in the axial direction or continuously in a spiral shape.

[0012] With this configuration, the axial cross-section of the joint surface has multiple recesses aligned in the axial direction, and the brazing material fills these recesses, allowing it to more effectively withstand axial loads and further suppress delamination of the intermetallic compound.

[0013] Furthermore, the load-receiving portion is composed of a load-receiving projection that protrudes radially from the stainless steel side joining surface, which is the stainless steel side of the joining surface, and it is preferable that the load-receiving projection is provided so as to fit into the brazing material portion.

[0014] With this configuration, the load-receiving projection that constitutes the load-receiving part fits into the brazing material, and this simple structure effectively receives axial loads, further suppressing delamination of intermetallic compounds.

[0015] Furthermore, the load-receiving part is, Note It is preferable that the load-bearing inclined surface is inclined with respect to the stainless steel side joint surface.

[0016] With this configuration, the load-receiving inclined surface in the load-receiving section can widely receive axial loads, thereby suppressing delamination of intermetallic compounds over a wide area, and thus further increasing the joint strength at the brazed joint.

[0017] Furthermore, the axial dimension of the load-receiving portion is as follows: Stainless steel side It is preferable that the thickness of the intermetallic compound layer formed between the bonding surface and the brazing material is greater than the thickness of the intermetallic compound layer formed between the bonding surface and the brazing material.

[0018] With this configuration, since the axial dimension of the load-bearing portion is larger than the layer thickness of the intermetallic compound, shear loads (i.e., axial loads), which are prone to causing delamination of the intermetallic compound from the joint surface, can be supported over a sufficient length in the axial direction. This type of support effectively prevents the above-mentioned loads from being directly applied to the intermetallic compound.

[0019] Furthermore, the dimension of the load-receiving portion in the direction intersecting the axial direction is the Stainless steel side It is preferable that the thickness of the intermetallic compound layer formed between the bonding surface and the brazing material is greater than the thickness of the intermetallic compound layer formed between the bonding surface and the brazing material.

[0020] According to this configuration, the load in the shear direction (i.e., the axial direction) can be received over a sufficient length in the above-described crossing direction, and even by such reception, it is possible to effectively suppress the load from being directly applied to the intermetallic compound.

[0021] Further, the outer diameter of one of the stainless steel pipe and the aluminum pipe is larger than the inner diameter of the other pipe, one of the pipes is inserted into the other pipe by a predetermined length, and it is preferable that the brazing material portion is formed in a substantially cylindrical shape between the outer peripheral surface of one pipe and the inner peripheral surface of the other pipe.

[0022] According to this configuration, since the brazing material portion that joins the stainless steel pipe and the aluminum pipe to each other is formed in a substantially cylindrical shape, the direction of the load on the joining surface of the stainless steel pipe to the intermetallic compound is almost the shear direction (i.e., the axial direction). Since the direction of the load is almost the shear direction (i.e., the axial direction), it is possible to suppress the decrease in the strength of the intermetallic compound and further increase the joining strength.

[0023] Further, the outer diameter of one of the stainless steel pipe and the aluminum pipe is larger than the inner diameter of the other pipe, one of the pipes is inserted into the other pipe by a predetermined length, and the insertion end portion inserted into the other pipe in one pipe and the accommodation end portion that accommodates the insertion end portion inside in the other pipe are each preferably in a substantially cylindrical shape with no change in the diameter dimension in the axial direction.

[0024] According to this configuration, the brazing material portion between the substantially cylindrical insertion end portion and the accommodation end portion is formed in a substantially cylindrical shape, and the direction of the load on the joining surface of the stainless steel pipe to the intermetallic compound is almost the shear direction (i.e., the axial direction). Since the direction of the load is almost the shear direction (i.e., the axial direction), it is possible to suppress the decrease in the strength of the intermetallic compound and further increase the joining strength.

[0025] Also , machine The device is characterized by including the above-described joined pipe.

[0026] According to this device, since the connecting pipes are as described above, the joint strength of the brazed joint between the stainless steel pipe and the aluminum pipe in the connecting pipes can be increased.

[0027] Furthermore, the refrigeration cycle system of the present invention is as described above. Valve device It is characterized by having the following features.

[0028] This refrigeration cycle system, equipped with the aforementioned components, can enhance the joint strength at the brazed connections between stainless steel and aluminum piping within the system. [Effects of the Invention]

[0029] This invention Valve device Furthermore, according to the refrigeration cycle system, the joint strength at the brazed joint between stainless steel piping and aluminum piping can be increased. [Brief explanation of the drawing]

[0030] [Figure 1] This is a partial cross-sectional view showing an electric valve, which is a first embodiment of equipment equipped with connecting piping. [Figure 2] Figure 1 is a schematic diagram showing a refrigeration cycle system equipped with an electric valve. [Figure 3] This is an enlarged view of the wall portion including the first area A11 and the second area A12 in Figure 1, which share a common configuration. [Figure 4] This figure shows the load-receiving portion in the second embodiment in an enlarged cross-section similar to that in Figure 3. [Figure 5] This figure shows the load-bearing portion in the third embodiment in an enlarged cross-section similar to that of Figures 3(A) and 4(A). [Figure 6] This figure shows the load-receiving portion in the fourth embodiment in an enlarged cross-section similar to that in Figure 5. [Modes for carrying out the invention]

[0031] The following describes a first embodiment of the connecting piping, equipment, and refrigeration cycle system based on Figures 1 to 3.

[0032] Figure 1 is a partial cross-sectional view showing an electric valve, which is a first embodiment of equipment with connecting piping, and Figure 2 is a schematic diagram showing a refrigeration cycle system equipped with the electric valve shown in Figure 1. Figure 3 is an enlarged view of the wall portion in Figure 1, including the first area A11 and the second area A12, which have common configurations.

[0033] 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 main unit 11, a first connecting pipe 12, and a second connecting pipe 13. The electric valve 10 is a device that adjusts the flow rate of refrigerant flowing between the first connecting pipe 12 and the second connecting 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 main unit 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 main unit 11, which has a cylindrical shape with both ends closed. The first connecting pipe 12 is connected 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, so as to extend along the valve stem X1. The second connecting pipe 13 is connected at one end by brazing to the peripheral wall portion 111b of the valve chamber 11a in the valve body 111-1, so as to extend perpendicular to the valve stem X1. In this embodiment, the first connecting pipe 12 and the second connecting pipe 13 have equivalent configurations. Hereafter, the first connecting pipe 12 and the second connecting pipe 13 will be referred to simply as the connecting pipe 14, disregarding the concepts of first and second.

[0034] The connecting pipe 14 consists of a cylindrical stainless steel pipe 141 and an aluminum pipe 142 joined together in an axial direction D11 along the coaxial pipe axis X2. On the other hand, the valve body 111-1 to which the connecting pipe 14 is joined in the equipment body 11 is made of stainless steel. One end of the stainless steel pipe 141 of the connecting pipe 14 is brazed to the stainless steel valve body 111-1 using stainless steel brazing material. On the other hand, the joining of the stainless steel pipe 141 and the aluminum pipe 142 in the connecting pipe 14 is performed by brazing using aluminum brazing material. The brazing structure using this brazing material in the connecting pipe 14 will be described in detail later with reference to Figure 3.

[0035] First, before explaining the brazing structure of the electric valve 10, the outline of the refrigeration cycle system 1, which uses the electric valve 10 as an expansion valve 100 to circulate refrigerant, will be described with reference to Figure 2. The refrigeration cycle system 1 of this embodiment includes an expansion valve 100, an outdoor heat exchanger 200, an indoor heat exchanger 300, a flow path switching valve 400, and a compressor 500, which are 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.

[0036] The flow path of the refrigeration cycle can be 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.

[0037] 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 to the indoor heat exchanger 300, expansion valve 100, outdoor heat exchanger 200, flow path switching valve 400, and then 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 also controls the flow rate of the refrigerant. In Figure 2, the expansion valve 100 is installed so that liquid refrigerant flows from the outdoor heat exchanger 200 into the second pipe 102 (second connecting pipe 13) during cooling operation, and liquid refrigerant from the indoor heat exchanger 300 flows into the first pipe 101 (first connecting pipe 12) during heating operation. However, the system is not limited to this, and an expansion valve 100 may be provided so that liquid refrigerant from the outdoor heat exchanger 200 flows into the first pipe 101 during cooling operation, and liquid refrigerant from the indoor heat exchanger 300 flows into the second pipe 102 during heating operation.

[0038] Next, the brazing structure of the stainless steel pipe 141 and the aluminum pipe 142 in the jointed pipe 14 shown in Figure 1 will be explained with reference to Figure 3. Figure 3 shows the brazing structure in the jointed pipe 14 as a common enlarged view for the first area A11 and the second area A12 in Figure 1. In Figure 3, Figure 3(A) shows an enlarged view, and Figure 3(B) shows a cross-section of the joint end of the stainless steel pipe 141 along the pipe axis X2.

[0039] As shown in Figures 1 and 3, in this embodiment, at the joint between the stainless steel pipe 141 and the aluminum pipe 142, the inner diameter φB of the aluminum pipe 142 (the other pipe) is larger than the outer diameter φA of the stainless steel pipe 141 (the other pipe). The stainless steel pipe 141 and the aluminum pipe 142 are cylindrical pipes, and the aluminum pipe 142 is enlarged at the joint with the stainless steel pipe 141 to have the above-mentioned inner diameter φB. The stainless steel pipe 141 is inserted into the enlarged portion of the aluminum pipe 142 by a predetermined insertion length L11. The above-mentioned enlargement of the aluminum pipe 142 is carried out over this insertion length L11 in the axial direction D11. The stainless steel pipe 141 is inserted into the inner surface 142a of the aluminum pipe 142 up to the stepped portion 142a-1 that is created by the enlargement at a position away from the opening by the insertion length L11.

[0040] Furthermore, joining pipes is not limited to expanding the diameter of one pipe and inserting the other pipe into the expanded portion, as in this embodiment. For example, one pipe may be reduced in diameter and its reduced portion inserted into the other pipe, the opposite of this embodiment. Alternatively, two pipes with different diameters may be prepared, and the smaller diameter pipe may be inserted into the larger diameter pipe. In this case, the insertion depth may be set by punching a mark inside or outside the pipe.

[0041] In this embodiment, the insertion end 141-1 of the stainless steel pipe 141 and the housing end 142-1 of the aluminum pipe 142 are both substantially cylindrical in shape, with no change in diameter in the axial direction D11. The insertion end 141-1 is the portion of the stainless steel pipe 141 that is inserted into the aluminum pipe 142. The housing end 142-1 is the portion of the aluminum pipe 142 that houses the insertion end 141-1 inside. Between the insertion end 141-1 of the stainless steel pipe 141 and the housing end 142-1 of the aluminum pipe 142, a brazed joint 143 is formed as a result of brazing with aluminum brazing material 143a. This brazed joint 143 is formed in a substantially cylindrical shape over the insertion length L11.

[0042] Furthermore, a load-receiving portion 144 is provided on the joint surface between the stainless steel pipe 141 and the brazing material portion 143 to receive a load F11 in the axial direction D11. In this embodiment, the load-receiving portion 144 is composed of a load-receiving projection 144a that protrudes radially D12 from the stainless steel side joint surface 141a, which is the side of the joint surface that faces the stainless steel pipe 141. The load-receiving projection 144a in this embodiment has a curved convex shape that protrudes so that its outer surface forms part of a sphere. This load-receiving projection 144a is provided embedded in the brazing material portion 143. The load-receiving projection 144a is formed by making the stainless steel pipe 141 protrude from the inside to the outside, and a recess 141c is formed on the inner surface 141b of the stainless steel pipe 141 at the location corresponding to the load-receiving projection 144a. In addition, in this embodiment, four load-receiving projections 144a are arranged at 90° intervals in the circumferential direction D13. The load-receiving section 144, having these four load-receiving protrusions 144a, receives the load F11 in the axial direction D11 by inserting each load-receiving protrusion 144a into the brazing material section 143. Note that in Figure 3(B), the load-receiving protrusions 144a that have entered the brazing material section 143, which were too small to be shown in Figure 1, are shown in a larger, more emphasized size.

[0043] Here, the width dimension W11 of each load-receiving projection 144a in the load-receiving portion 144 in the axial direction D11 is greater than the layer thickness t11 of the intermetallic compound 145 formed between the stainless steel side joining surface 141a and the aluminum brazing material 143a. More specifically, this projection width dimension W11 is greater than twice the layer thickness t11 of the intermetallic compound 145.

[0044] Furthermore, the thickness t11 of the intermetallic compound 145 is affected by the brazing temperature and heating time, so there is a range in the specific value, but it is generally a few μm to 10 μm. This value corresponds to a thickness of approximately 3 to 25% of the clearance t12 between the stainless steel side joint surface 141a and the aluminum pipe 142 when there is no brazing material 143a. This clearance t12 is the thickness of the brazing material 143a between the portion of the stainless steel side joint surface 141a where the load-receiving protrusion 144a is not formed and the aluminum pipe 142.

[0045] Furthermore, the height dimension W12 of each load-receiving projection 144a in the load-receiving portion 144 in the direction intersecting the axial direction D11, i.e., the radial direction D12, is greater than the layer thickness t11 of the intermetallic compound 145. More specifically, the height dimension W12 is greater than 1 times the layer thickness t11 of the intermetallic compound 145. In addition, this height dimension W12 is greater than the clearance t12 between the stainless steel side joint surface 141a and the aluminum pipe 142.

[0046] The first embodiment described above, comprising a jointed pipe 14, an electric valve 10 as an example of equipment, and a refrigeration cycle system 1 equipped with this electric valve 10 as an expansion valve 100, can achieve the following effects. Specifically, according to this embodiment, the load-receiving portion 144 provided on the joint surface between the stainless steel pipe 141 and the brazing material portion 143 can receive the load F11 in the shear direction (i.e., the axial direction D11), which is prone to causing the intermetallic compound 145 to peel off from the joint surface. By receiving the load in this way, the above-mentioned load F11 is prevented from being directly applied to the intermetallic compound 145, thereby suppressing the peeling of the intermetallic compound 145, and thus the aluminum pipe 142 can resist the force in the axial direction D11. In other words, according to this embodiment, the joint strength of the brazed joint between the stainless steel pipe 141 and the aluminum pipe 142 can be increased.

[0047] In this embodiment, the load-receiving portion 144 is composed of a load-receiving projection 144a that protrudes radially D12 from the stainless steel side joint surface 141a, and the load-receiving projection 144a is positioned to fit into the brazing material portion 143. With this configuration, the load-receiving projection 144a that constitutes the load-receiving portion 144 fits into the brazing material portion 143, and this simple configuration effectively receives the load F11 in the axial direction D11, further suppressing the peeling of the intermetallic compound 145.

[0048] Furthermore, in this embodiment, the width dimension W11 of the protrusion 144a of the load-receiving protrusion 144a constituting the load-receiving portion 144 in the axial direction D11 is greater than the layer thickness t11 of the intermetallic compound 145. With this configuration, the load F11 in the shear direction (i.e., the axial direction D11), which is likely to cause delamination of the intermetallic compound 145, can be received over a sufficient length in the axial direction D11. And by receiving the load in this way, it is possible to effectively prevent the above load F11 from being directly applied to the intermetallic compound 145.

[0049] Furthermore, in this embodiment, the height dimension W12 of the convex portion 144a in the radial direction D12 is greater than the layer thickness t11 of the intermetallic compound 145. With this configuration, the load F11 in the shear direction (i.e., the axial direction D11) can be received over a sufficient length in the radial direction D12, and even with such support, it is possible to effectively prevent the load F11 from being directly applied to the intermetallic compound 145.

[0050] Furthermore, in this embodiment, the inner diameter φB of the aluminum pipe 142 is larger than the outer diameter φA of the stainless steel pipe 141. The stainless steel pipe 141 is inserted into the aluminum pipe 142 for a length L11, and a brazing material portion 143 is formed in a substantially cylindrical shape between the outer surface of the stainless steel pipe 141 and the inner surface of the aluminum pipe 142. With this configuration, since the brazing material portion 143 that joins the stainless steel pipe 141 and the aluminum pipe 142 is formed in a substantially cylindrical shape, the direction of the load on the intermetallic compound 145 is almost entirely in the shear direction (i.e., the axial direction D11). Since the direction of the load is almost entirely in the shear direction (i.e., the axial direction D11), the reduction in strength of the intermetallic compound 145 can be suppressed and the joint strength can be further increased.

[0051] Furthermore, in this embodiment, the insertion end 141-1 of the stainless steel pipe 141 and the housing end 142-1 of the aluminum pipe 142 are both substantially cylindrical in shape, with no change in diameter in the axial direction D11. With this configuration, the brazing material portion 143 between the substantially cylindrical insertion end 141-1 and the housing end 142-1 is formed in a substantially cylindrical shape, and the direction of the load on the intermetallic compound 145 is almost entirely in the shear direction (i.e., the axial direction D11). Since the direction of the load is almost entirely in the shear direction (i.e., the axial direction D11), the reduction in strength of the intermetallic compound 145 can be suppressed, and the joint strength can be further increased.

[0052] This concludes the explanation of the first embodiment. Next, the second embodiment will be described. In this second embodiment, the load-receiving projection 144a, which is a component of the load-receiving part 144, is modified so that the direction of the protrusions and indentations is reversed to a concave shape compared to the first embodiment. The following explanation will focus only on this modification.

[0053] Figure 4 shows the load-receiving section in the second embodiment, in an enlarged cross-section similar to that in Figure 3. In Figure 4, components equivalent to those shown in Figure 3 are given the same reference numerals as in Figure 3, and redundant explanations of these equivalent components will be omitted below.

[0054] In the second embodiment, the load-bearing portion 244 is composed of a load-bearing recess 244a in the stainless steel pipe 141 that is recessed radially D12 from the stainless steel side joint surface 141a. The load-bearing recess 244a in this embodiment has a curved concave shape in which its inner surface is recessed so as to form part of a sphere. The brazing material portion 143 is fitted into this load-bearing recess 244a. The load-bearing recess 244a is formed by making the stainless steel pipe 141 protrude from the outside to the inside, and a convex portion 241c is formed on the inner surface 141b of the stainless steel pipe 141 at a location corresponding to the load-bearing recess 244a. Four of these load-bearing recesses 244a are arranged at 90° intervals in the circumferential direction D13 around the pipe axis X2. The load-receiving section 244, having these four load-receiving recesses 244a, receives the load F11 in the axial direction D11 by inserting the brazing material portion 143, which is formed between it and the aluminum pipe 142, into each load-receiving recess 244a. In Figure 4(B), as in Figure 3(B), the load-receiving recesses 244a are shown in a larger, more exaggerated manner.

[0055] It goes without saying that, as with the first embodiment described above, the second embodiment also makes it possible to increase the joint strength at the brazed joint between the stainless steel pipe 141 and the aluminum pipe 142.

[0056] Furthermore, in this embodiment, the load-receiving portion 244 is composed of a load-receiving recess 244a that is recessed radially D12 from the stainless steel side joining surface 141a, and the brazing material portion 143 is provided by fitting into the load-receiving recess 244a. With this configuration, the brazing material 143a can be effectively received by fitting into the inside of the load-receiving recess 244a that constitutes the load-receiving portion 244, thereby further suppressing the peeling of the intermetallic compound 145.

[0057] This concludes the explanation of the second embodiment. Next, we will describe the third embodiment. This third embodiment is a modified version of the second embodiment described above, in which the shape of the components of the load-receiving portion 244 has been changed. The following explanation will focus only on this modification.

[0058] Figure 5 shows the load-bearing section in the third embodiment, in an enlarged cross-section similar to that of Figures 3(A) and 4(A). In Figure 5, components equivalent to those shown in Figure 4 are given the same reference numerals as in Figure 4, and redundant explanations of these equivalent components will be omitted below.

[0059] In the third embodiment, the load-receiving portion 344 is formed in the stainless steel pipe 141 in a shape that is recessed radially D12 from the stainless steel side joint surface 141a, similar to the second embodiment described above. However, the load-receiving portion 344 in this embodiment is composed of a load-receiving groove 344a that is continuously recessed around the circumference in the circumferential direction D13. This load-receiving groove 344a has a rectangular groove shape that is recessed so that its cross-section is rectangular. Furthermore, this load-receiving groove 344a is formed by machining the stainless steel side joint surface 141a, and no corresponding protrusions or the like are formed on the inner surface 141b of the stainless steel pipe 141 at the location corresponding to the load-receiving groove 344a. The load-receiving groove 344a is used to receive the load F11 in the axial direction D11 by inserting the brazing material portion 143 formed between it and the aluminum pipe 142 into the load-receiving groove 344a.

[0060] It goes without saying that, as with the first embodiment described above, the third embodiment also makes it possible to increase the joint strength at the brazed joint between the stainless steel pipe 141 and the aluminum pipe 142.

[0061] Furthermore, in this embodiment as well, the simple configuration of inserting the brazing material 143a inside the load-receiving groove 344a effectively receives the load F11 in the axial direction D11, thereby further suppressing the peeling of the intermetallic compound 145.

[0062] This concludes the explanation of the third embodiment. Next, the fourth embodiment will be described. This fourth embodiment is a modification of the third embodiment described above, and the shape of the load-receiving groove 344a, which is a component of the load-receiving part 344 and is formed by machining, has been changed. The following explanation will focus only on this modification.

[0063] Figure 6 shows the load-bearing section in the fourth embodiment, in an enlarged cross-section similar to that in Figure 5. In Figure 6, components equivalent to those shown in Figure 5 that are necessary for explanation are given the same reference numerals as in Figure 5, and redundant explanations of these equivalent components will be omitted below.

[0064] The load-receiving portion 444 in the fourth embodiment, like the third embodiment described above, is composed of a load-receiving groove 444a that is recessed radially D12 from the stainless steel side joint surface 141a in the stainless steel pipe 141 and is continuous around the circumference in the circumferential direction D13. However, the load-receiving groove 444a in this embodiment has a triangular groove shape with a triangular cross-section, and multiple grooves are provided side by side in the axial direction D11 to form a load-receiving portion 444 with a sawtooth cross-section. As an alternative example of a load-receiving groove that constitutes a load-receiving portion with a sawtooth cross-section, the load-receiving grooves may be provided continuously in a spiral shape.

[0065] Furthermore, each load-receiving groove 444a, which is aligned in the axial direction D11, has a load-receiving inclined surface 444a-1 that is inclined with respect to the stainless steel side joint surface 141a and receives the load F11. In other words, the load-receiving section 444 has a plurality of load-receiving inclined surfaces 444a-1 aligned in the axial direction D11. Then, the brazing material 143a of the brazing material section 143 is inserted into each of the plurality of load-receiving grooves 444a, each of which has a load-receiving inclined surface 444a-1.

[0066] It goes without saying that, as with the first embodiment described above, the fourth embodiment also makes it possible to increase the joint strength at the brazed joint between the stainless steel pipe 141 and the aluminum pipe 142.

[0067] Furthermore, in this embodiment as well, similar to the second embodiment described above, the simple configuration of inserting the brazing material 143a inside the load-receiving groove 444a effectively receives the load F11 in the axial direction D11, thereby further suppressing the peeling of the intermetallic compound 145.

[0068] Furthermore, in this embodiment, multiple load-receiving grooves 444a are provided in the axial direction D11. With this configuration, the brazing material 143a enters the multiple load-receiving grooves 444a arranged on the stainless steel side joint surface 141a, thereby more effectively receiving the load F11 in the axial direction D11 and further suppressing the peeling of the intermetallic compound 145.

[0069] Furthermore, in this embodiment, the load-receiving portion 444 has a load-receiving inclined surface 444a-1 that is inclined with respect to the stainless steel side joining surface 141a. With this configuration, the load-receiving inclined surface 444a-1 can widely receive the load F11 in the axial direction D11, thereby suppressing peeling of the intermetallic compound 145 over a wide area, and thus the joint strength at the brazed joint can be further increased.

[0070] Furthermore, the first to fourth 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. As long as such modifications still incorporate the configuration of the connecting piping, equipment, and refrigeration cycle system of the present invention, they are of course included within the scope of the present invention.

[0071] For example, in the first to fourth embodiments described above, an electric valve 10 used as an expansion valve 100 in a refrigeration cycle system 1 and a connecting pipe 14 as its component are exemplified as examples of connecting piping and equipment. However, the equipment is not limited to an electric valve as an expansion valve, but may also be various valve devices other than electric valves, such as solenoid valves and manual valves, or various valve devices other than expansion valves, such as flow path switching valves, check valves, and shut-off valves. Furthermore, the equipment is not limited to valve devices, but may also be various equipment such as accumulators, oil separators, compressors, various heat exchangers, dryers, switches, and sensors, as long as it has connecting piping. In addition, the connecting piping is not limited to application to valve devices, but may also be applied to the various equipment described above.

[0072] Furthermore, in the first to fourth embodiments described above, an electric valve 10 equipped with two connecting pipes 14, a first connecting pipe 12 and a second connecting pipe 13, and the connecting pipes 14 as its components are exemplified as examples of connecting pipes and equipment. And, as an example of load-bearing parts provided on connecting pipes, load-bearing parts 144, ..., 444 provided on all connecting pipes 14 are exemplified. However, the connecting pipes, equipment, and load-bearing parts provided on connecting pipes are not limited to these. The number of connecting pipes can be set to any number, and load-bearing parts may be formed only on some of the connecting pipes that are necessary among the multiple connecting pipes, depending on the operating environment.

[0073] Furthermore, in the first to fourth embodiments described above, a jointed pipe 14 in which a stainless steel pipe 141 is inserted into an aluminum pipe 142 is exemplified as an example of a jointed pipe. However, the jointed pipe is not limited to this, and conversely to the embodiments described above, the inner diameter of the stainless steel pipe may be made larger than the outer diameter of the aluminum pipe at the joint so that the aluminum pipe is inserted into the stainless steel pipe.

[0074] Furthermore, in the first to fourth embodiments described above, various load-receiving parts are exemplified as examples of load-receiving parts. Specifically, load-receiving parts 144 and 244 are exemplified, consisting of four load-receiving protrusions 144a and load-receiving recesses 244a arranged at 90° intervals in the circumferential direction D13. Also exemplified are load-receiving parts 344 consisting of a load-receiving groove 344a that extends continuously around the circumference in the circumferential direction D13, and load-receiving parts 444 consisting of multiple such load-receiving grooves 444a arranged in the axial direction D11. However, load-receiving parts are not limited to these, and their specific shape is not restricted as long as they can receive loads in the axial direction. However, as mentioned above, load-receiving parts consisting of protrusions, recesses, or one or more grooves can effectively receive loads with a simple configuration.

[0075] Furthermore, in the first to fourth embodiments described above, load-bearing portions 144, ..., 444 are exemplified as examples of load-bearing portions in which the dimension in the axial direction D11 is greater than the layer thickness t11 of the intermetallic compound 145. In addition, the dimension in the intersecting direction, i.e., the radial direction D12, of all these load-bearing portions 144, ..., 444 is also greater than the layer thickness t11 of the intermetallic compound 145. However, the load-bearing portions are not limited to these, and the dimensions in the axial direction and intersecting direction may be the same as or smaller than the layer thickness of the intermetallic compound. However, as described above, by making the dimensions in the axial direction and intersecting direction greater than the layer thickness t11 of the intermetallic compound 145, it is possible to effectively suppress the direct application of the load F11 to the intermetallic compound 145.

[0076] Furthermore, in the first to fourth embodiments described above, a brazing material portion 143 formed in a substantially cylindrical shape according to the shape of each pipe is exemplified as an example of a brazing material portion formed between stainless steel pipe and aluminum pipe. However, the brazing material portion is not limited to this, and stainless steel pipe and aluminum pipe with cylindrical shapes other than cylinders may be used to form a brazing material portion with a cylindrical shape other than cylinder. However, as described above, by forming the brazing material portion 143 in a substantially cylindrical shape, the direction of the load on the intermetallic compound 145 can be made almost in the shear direction (i.e., the axial direction D11), thereby suppressing the reduction in strength of the intermetallic compound 145 and further increasing the joint strength. [Explanation of Symbols]

[0077] 1. Refrigeration cycle system 10 Electric valve 11. Main unit of the device 11a Valve chamber 11b Valve body 11c Valve seat member 12 1st joint piping 13 2nd joint pipe 14. Joint piping 100 Expansion valve 101 First Piping 102 Second Piping 200 Outdoor heat exchanger 300 Indoor heat exchanger 400 Flow path switching valve 500 Compressor 111 Housing 111-1 Valve body 111-2 Case 111a Bottom wall part 111b Peripheral wall part 141 Stainless steel piping 141-1 Plug end 141a Stainless steel side joint surface 141b,142a Inner surface 141c recess 142 Aluminum Piping 142-1 Enclosure end 142a-1 Stepped section 143 Brazing material section 143a Brazing material 144,244,344,444 Load-bearing section 144a Load-receiving protrusion 145 Intermetallic compounds 241c protrusion 244a Load-bearing recess 344a, 444a Load-bearing groove 444a-1 Load-bearing inclined surface D11 Axial direction D12 Radial D13 Circumferential direction F11 Load L11 Insertion length t11 layer thickness t12 clearance W11 Convex width dimension W12 Convex height dimension X1 valve stem X2 Piping shaft φA Outer diameter φB inner diameter

Claims

1. A valve device comprising a device body having a stainless steel valve body with a valve chamber formed inside, and a connecting pipe in which stainless steel piping and aluminum piping are joined in the axial direction, One end of the stainless steel pipe is connected to the valve body in the main body of the equipment, The other end of the stainless steel pipe is connected to the aluminum pipe. The stainless steel pipe and the aluminum pipe are brazed together with brazing material, and a brazing material portion is formed between the stainless steel pipe and the aluminum pipe. Of the stainless steel side joint surface, which is the joint surface between the stainless steel pipe and the brazing material on the stainless steel pipe side, and the aluminum side joint surface, which is the joint surface between the aluminum pipe and the brazing material on the aluminum pipe side, a load-receiving portion that receives the axial load is provided only on the stainless steel side joint surface. The load-receiving portion is formed by a load-receiving projection that protrudes from the stainless steel side joining surface toward the cylindrical outer surface of the aluminum side joining surface, The valve device is characterized in that the load-receiving projection faces the cylindrical outer surface of the aluminum-side joining surface, and the load-receiving projection is provided embedded in the brazing material portion.

2. A valve device comprising a device body having a stainless steel valve body with a valve chamber formed inside, and a connecting pipe in which stainless steel piping and aluminum piping are joined in the axial direction, One end of the stainless steel pipe is connected to the valve body in the main body of the equipment, The other end of the stainless steel pipe is connected to the aluminum pipe. The stainless steel pipe and the aluminum pipe are brazed together with brazing material, and a brazing material portion is formed between the stainless steel pipe and the aluminum pipe. Of the stainless steel side joint surface, which is the joint surface between the stainless steel pipe and the brazing material on the stainless steel pipe side, and the aluminum side joint surface, which is the joint surface between the aluminum pipe and the brazing material on the aluminum pipe side, a load-receiving portion that receives the axial load is provided only on the stainless steel side joint surface. The load-receiving portion is formed as a load-receiving recess that is recessed in a direction away from the cylindrical outer surface of the aluminum-side joining surface from the stainless steel-side joining surface. The valve device is characterized in that the load-receiving recess faces the cylindrical outer surface of the aluminum-side joining surface, and the brazing material portion is provided by fitting into the load-receiving recess.

3. The load-receiving recess is composed of a load-receiving groove that is recessed radially from the stainless steel side joining surface and extends in a direction intersecting the radial direction. The valve device according to claim 2, characterized in that the brazing material portion is provided by fitting into the load-receiving groove.

4. The valve device according to claim 3, characterized in that the load-receiving grooves are arranged in a plurality in the axial direction or arranged continuously in a spiral shape.

5. The valve device according to claim 1 or 2, characterized in that the load-receiving portion has a load-receiving inclined surface that is inclined with respect to the stainless steel side joining surface.

6. The valve device according to claim 1 or 2, characterized in that the axial dimension of the load-receiving portion is greater than the thickness of the intermetallic compound layer formed between the load-receiving portion and the brazing material between it and the stainless steel side joint surface.

7. The valve device according to claim 1 or 2, characterized in that the dimension of the load-receiving portion in the intersecting direction that intersects the axial direction is greater than the thickness of the intermetallic compound layer formed between the load-receiving portion and the brazing material between it and the stainless steel side joining surface.

8. The valve device according to claim 1 or 2, characterized in that the stainless steel pipe and the aluminum pipe have an inner diameter greater than the outer diameter of one pipe, the one pipe is inserted into the other pipe by a predetermined length, and the brazing material is formed in a substantially cylindrical shape between the outer surface of the one pipe and the inner surface of the other pipe.

9. The valve device according to claim 1 or 2, characterized in that the stainless steel pipe and the aluminum pipe have an inner diameter greater than the outer diameter of the other pipe, the one pipe is inserted into the other pipe by a predetermined length, and the insertion end of the one pipe that is inserted into the other pipe and the housing end of the other pipe that houses the insertion end are both substantially cylindrical in shape, with no change in diameter in the axial direction.

10. A refrigerated cycle characterized by being equipped with a valve device according to any one of claims 1 to 4. Lu system.

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