JP7645839B2 - Refrigerant piping, refrigerant piping connection structure, and valve device - Google Patents

Description

The present invention relates to refrigerant piping, a connection structure for refrigerant piping, and a valve device.

Conventionally, in air conditioning devices such as room air conditioners, the refrigerant is returned to the compressor via the compressor, outdoor heat exchanger, expansion valve, and indoor heat exchanger connected via refrigerant piping during cooling operation, and the refrigerant is returned to the compressor via the compressor, indoor heat exchanger, expansion valve, and outdoor heat exchanger during heating operation, reversing the refrigerant return direction. In this way, a slide-type switching valve having a valve body that is freely slidably installed inside the valve body is widely used as a flow path switching valve (so-called four-way switching valve), which is a valve device that reverses the refrigerant return path (see, for example, Patent Document 1). In such air conditioning devices, the refrigerant piping installed inside the device and the joint members (refrigerant piping) installed as the discharge pipe and suction pipe of the slide-type switching valve are connected by brazing.

JP 2004-125238 A

The valve device (slide-type switching valve) generally has a body made of brass, and other parts such as coupling members are made of copper. However, due to the sudden rise in the price of copper in recent years, there is a trend to switch from copper, which has traditionally been used as a material for coupling members in valve devices, to stainless steel. On the other hand, in air conditioners in which valve devices are installed, copper is still used as the material for refrigerant piping, as in the past, due to its ease of processing and stable performance. Therefore, since the stainless steel coupling members of the valve device and the copper refrigerant piping of the air conditioner are made of different materials, there is a problem that it is difficult to simply connect them by brazing as in the past.

Furthermore, when using flux to ensure wettability when brazing the valve device joint parts to the air conditioning system refrigerant piping, the flux is difficult to remove, so flux has not been used in the past. In other words, the refrigerant piping, which contains stainless steel, and the joint parts, which contain copper, are made of different materials, and no flux is used, making it extremely difficult to braze them together.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a refrigerant pipe, a refrigerant pipe connection structure, and a valve device that can be easily connected using brazing even if the pipes are made of different materials.

The refrigerant piping of the present invention is a refrigerant piping made of stainless steel, characterized in that a thin-plate connection auxiliary part made of copper or a copper alloy is provided on the inner surface, the outer surface, or both of them at at least one longitudinal end, a molten and solidified layer of brazing material is formed between the inner surface, the outer surface, or both of them and the connection auxiliary part , and the connection auxiliary part is positioned by being pressed against the inner surface, the outer surface, or both of them of the refrigerant piping via the molten and solidified layer .

According to the present invention, even if the refrigerant pipe itself is made of stainless steel, at least one end of the longitudinal direction has an inner peripheral surface, an outer peripheral surface, or both of them, which is provided with a thin plate-shaped connection auxiliary part made of copper or a copper alloy joined via a molten and solidified layer of a brazing material (i.e., by brazing), so that the pipe can be easily connected to a connection target by brazing via the connection auxiliary part. In addition, compared to a case where a member such as a copper ring or sleeve is provided for connection to another refrigerant pipe that is a connection target, the thickness of the connection auxiliary part can be made thinner, thereby reducing connection costs such as material costs. Furthermore, since the heat of brazing when connecting to a connection target is easily transferred, overheating during the brazing can be suppressed, the clearance with the connection target can be stabilized, and the quality of the brazing can be improved.

In this case, in the refrigerant pipe of the present invention, the connection auxiliary part is arranged by being pressed against the inner circumferential surface, the outer circumferential surface, or both of the refrigerant pipe via the molten solidified layer . With this configuration, the effort of holding the connection auxiliary part at the arrangement portion by spot welding or the like is eliminated, and the connection auxiliary part can be easily arranged. In addition, it is preferable that the connection auxiliary part is arranged in a state where it is rolled into a C-shape when viewed from a direction perpendicular to the axial direction. With this configuration, when the connection auxiliary part is arranged on the inner circumferential surface at the end of the refrigerant pipe, the connection auxiliary part is pressed against the inner circumferential surface of the refrigerant pipe by an elastic force for maintaining the shape in the direction of opening from the C-shape, and when the connection auxiliary part is arranged on the outer circumferential surface at the end of the refrigerant pipe, the connection auxiliary part is held on the outer circumferential surface of the refrigerant pipe by an elastic force for maintaining the shape in the direction of rolling into the C-shape, so that the connection auxiliary part can be easily arranged with a simple structure.

Furthermore, in the refrigerant piping of the present invention, it is preferable that the connection auxiliary part is an annular cylindrical body. With this configuration, the connection auxiliary part of the cylindrical body can be expanded in the outer diameter direction or contracted in the inner diameter direction depending on the placement location, eliminating the need to hold it in the placement location by spot welding, for example, and making it easy to place.

In addition, in the refrigerant pipe of the present invention, it is preferable that the connection auxiliary part is formed to extend to the end face at the one end. According to this configuration, the connection auxiliary part is provided not only on the surface (inner or outer circumferential surface) that contacts the surface (outer or inner circumferential surface) of the refrigerant pipe to be connected, but also extending to the end face of the refrigerant pipe, so that when the material of the connection object is the same copper or copper alloy as the connection auxiliary part, a good fillet is easily formed. As a result, the connection is made without gaps, the airtightness of the brazing part can be reliably ensured, and the reliability of the connection can be further ensured. Furthermore, in this case, it is preferable that the connection auxiliary part has a flange part facing the end face, and a molten and solidified layer of the brazing material is formed between the flange part and the end face. As a result, it is possible to easily provide the connection auxiliary part that extends to the end face of the refrigerant pipe, so that the reliability of the connection can be more easily ensured.

In addition, in the refrigerant piping of the present invention, it is preferable that the connection auxiliary part has a U-shaped cross section, and that one end part is inserted into the inner periphery of the U-shape. With this configuration, it is possible to easily provide a connection auxiliary part that covers not only both the outer periphery and inner periphery of the end part of the refrigerant piping, but also the end face of the refrigerant piping as a whole. Therefore, when the material of the connection object is the same copper or copper alloy as the connection auxiliary part, a good fillet is easily formed. This makes it possible to easily realize a configuration that can be joined without gaps, reliably ensures airtightness of the brazed part, and further ensures the reliability of the connection.

Furthermore, in the refrigerant piping of the present invention, it is preferable that a piping stopper portion that regulates the insertion depth of another refrigerant piping to be connected is formed at the portion where the inner end portion of the connection auxiliary portion in the longitudinal direction of the refrigerant piping is located. With this configuration, it is possible to easily regulate the insertion depth of the refrigerant piping to be connected (joint member) and prevent dripping of the brazing material used in brazing.

In this case, it is preferable that the pipe stopper portion protrudes outward from the outer peripheral surface of the refrigerant pipe or inward from the inner peripheral surface. With this configuration, the pipe stopper portion can be formed integrally with the refrigerant pipe, eliminating the need to provide the pipe stopper portion separately and reducing the number of parts.

Furthermore, in the refrigerant pipe of the present invention, it is preferable that the inner end of the connection auxiliary part in the longitudinal direction when it is attached to the refrigerant pipe is formed with a pipe stopper part that regulates the insertion depth of the other refrigerant pipe to be connected. With this configuration, it is possible to easily regulate the insertion depth of the refrigerant pipe (joint member) to be connected and to prevent dripping of the brazing material used in brazing.

In this case, it is preferable that the pipe stopper portion protrudes outward from the outer peripheral surface of the connection auxiliary portion, inward from the inner peripheral surface, or both. With this configuration, the pipe stopper portion can be formed integrally with the connection auxiliary portion, eliminating the need to provide the pipe stopper portion separately, and reducing the number of parts. It is also preferable that the thickness of the connection auxiliary portion is thinner than the thickness of the refrigerant pipe. It is also preferable that the thickness of the molten solidified layer is thinner than the thickness of the connection auxiliary portion.

The present invention provides a connection structure for refrigerant piping in which a first refrigerant piping and a second refrigerant piping are connected by brazing, the first refrigerant piping being made of stainless steel, a thin-plate connection assistant part made of a second metal material different from stainless steel is joined to an inner circumferential surface, an outer circumferential surface, or both surfaces of an end portion of the second refrigerant piping via a molten and solidified layer of a brazing material, and the connection assistant part is arranged by being pressed against the inner circumferential surface, the outer circumferential surface, or both surfaces of the first refrigerant piping via the molten and solidified layer, and the second refrigerant piping being made of the second metal material, or a thin-plate connection assistant part made of the second metal material is joined to an outer circumferential surface, an inner circumferential surface, or both surfaces of the end portion of the first refrigerant piping via a molten and solidified layer of the brazing material , and the connection assistant part is arranged by being pressed against the inner circumferential surface, the outer circumferential surface, or both surfaces of the second refrigerant piping via the molten and solidified layer . According to the present invention, even if the first refrigerant piping is made of stainless steel, a connection auxiliary part made of a second metal material (e.g., copper, copper alloy, aluminum, etc.) is provided on the inner surface, outer surface, or both surfaces of the end part of the second refrigerant piping, so that the first refrigerant piping can be easily connected by brazing to the second refrigerant piping to be connected, which is made of the second metal material or has a connection auxiliary part made of the second metal material on the inner surface, outer surface, or both surfaces of the end part of the first refrigerant piping.

Furthermore, in the refrigerant piping connection structure of the present invention, the connection auxiliary part of the first refrigerant piping is formed to extend to the end face of the second refrigerant piping side end of the first refrigerant piping, and when the second refrigerant piping is not made of the second metal material , the connection auxiliary part is preferably formed to extend to the end face of the first refrigerant piping side end of the second refrigerant piping. According to such a structure, the connection auxiliary part is provided not only on the surfaces that contact each other in both the first and second refrigerant piping, i.e., on the surfaces (outer peripheral surfaces or inner peripheral surfaces) of both connection target side ends, but also on the end faces of both connection target side ends, so that when the material of the second refrigerant piping to be connected to the first refrigerant piping or the connection auxiliary part provided on the first refrigerant piping side end is made of the same second metal material as the connection auxiliary part of the first refrigerant piping, a fillet is easily formed. As a result, the connection is made without any gaps, the airtightness of the brazed part can be reliably ensured, and the reliability of the connection can be further ensured . It is also preferable that the connection assistant part has a flange part facing the end face, and a melted and solidified layer of the brazing material is formed between the flange part and the end face. It is also preferable that the thickness of the connection assistant part is thinner than the thickness of the first refrigerant pipe. It is also preferable that the thickness of the melted and solidified layer is thinner than the thickness of the connection assistant part.

The valve device of the present invention is a valve device in which a coupling member is connected to a valve body, and is characterized in that any of the above-mentioned refrigerant piping is used as the coupling member. According to this invention, as with the above, even if the coupling member is made of stainless steel, the connection side end of the coupling member is provided with a connection auxiliary part made of copper or copper alloy on its inner peripheral surface, outer peripheral surface, or both, so that it can be easily connected to the refrigerant piping to be connected by brazing. In addition, the same effects as those of the above-mentioned refrigerant piping can be obtained.

The refrigerant piping, refrigerant piping connection structure, and valve device of the present invention can be easily connected using brazing even if the materials are different.

FIG. 2 is a cross-sectional view showing a slide type switching valve according to the embodiment. 2 is a cross-sectional view showing an end portion of a coupling member provided in the slide type switching valve of FIG. 1, illustrating a state in which a connection auxiliary portion is provided on an inner peripheral surface. FIG. 3 is an enlarged cross-sectional view showing a main part at an end portion of the joint member in FIG. 2. [0023] FIG. 13 is a cross-sectional view showing an end portion of a coupling member according to a modified example, with a connection auxiliary portion provided on the inner circumferential surface. FIG. 13 is a cross-sectional view showing an end portion of a coupling member according to Modification 2, in which a connection auxiliary portion according to Modification 2 is provided on the inner circumferential surface. FIG. 6A is a front view of a connection auxiliary portion provided in the joint member of FIG. 5, as viewed from a direction perpendicular to the axial direction, and FIG. 6B is a cross-sectional view taken along the axial direction. 6 is an enlarged cross-sectional view of a main portion showing a connection state between a joint member and a refrigerant pipe in the slide type switching valve of FIG. 5 . 13 is a cross-sectional view showing an end portion of a coupling member according to Modification 3, in which a connection auxiliary portion according to Modification 3 is provided on the inner circumferential surface. FIG. 9A and 9B are front and sectional views taken along the axial direction of a connection auxiliary portion provided in the joint member of FIG. 8 ; FIG. 9A is a front view taken along a direction perpendicular to the axial direction of the connection auxiliary portion; FIG. 13 is a cross-sectional view showing an end portion of a coupling member according to Modification 4, in which a connection auxiliary portion according to Modification 4 is provided on the outer circumferential surface. FIG. FIG. 13 is a cross-sectional view showing an end portion of a coupling member according to Modification 5, in which a connection auxiliary portion according to Modification 5 is provided on the outer circumferential surface. 12 is an enlarged cross-sectional view showing a main part at an end portion of the joint member of FIG. 11. FIG. FIG. 13 is a cross-sectional view showing an end portion of a coupling member according to a sixth modified example, with a connection auxiliary portion according to the sixth modified example provided on the outer circumferential surface. 14 is an enlarged cross-sectional view of a main portion showing a connection state between a joint member and a refrigerant pipe in the slide type switching valve of FIG. 13. 13 is a cross-sectional view showing an end portion of a coupling member according to Modification 7, illustrating a state in which a connection auxiliary portion according to Modification 7 having a U-shaped cross section is provided from the inner peripheral surface to the outer peripheral surface. FIG. 13 is a cross-sectional view showing an end portion of a coupling member according to Modification 8, illustrating a state in which a connection auxiliary portion according to Modification 8 having a U-shaped cross section is provided from the inner peripheral surface to the outer peripheral surface. FIG. A cross-sectional view showing the end of a coupling member relating to variant 9, illustrating the state in which a connection auxiliary portion relating to variant 9 is provided, the cross section of which is U-shaped from the inner surface to the outer surface and which has a pipe stopper portion. A cross-sectional view showing the end of a coupling member relating to variant 10, illustrating the state in which a connection auxiliary portion relating to variant 10 is provided, the cross section of which is U-shaped from the inner surface to the outer surface and has a pipe stopper portion.

Below, the refrigerant piping, the refrigerant piping connection structure, and the valve device according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the four-way switching valve (slide type switching valve) 10 of this embodiment includes a pair of pistons 2L, 2R, a connecting plate 3, a valve seat 4, and a valve body 5 in a valve housing 1 as a "valve body."

The valve housing 1 is composed of a cylindrical part 11 made of a metal such as stainless steel and two cap parts 12L, 12R made of a metal such as stainless steel. The cap parts 12L, 12R are attached to the cylindrical part 11 so as to close the ends of the cylindrical part 11. The central axes of the cylindrical part 11 and the cap parts 12L, 12R are the axis X of the valve housing 1. The pair of pistons 2L, 2R are arranged opposite each other and can move back and forth while pressing the packing 21 against the inner circumferential surface of the cylindrical part 11. As a result, the inside of the valve housing 1 is divided by the two pistons 2L, 2R into a high pressure chamber 11A in the center and two working chambers, a first working chamber 12A and a second working chamber 12B on both sides of the high pressure chamber 11A. The connecting plate 3 is made of a metal plate and is installed between the pistons 2L, 2R so as to be arranged on the axis X of the valve housing 1, and holds the valve body 5 in the center. In addition, a through hole 3a is formed in the connecting plate 3. When the pistons 2L and 2R move, the valve body 5 slides on the valve seat 4 in conjunction with the connecting plate 3, and stops at a predetermined left or right position.

The valve seat 4 is disposed in the middle of the cylindrical portion 11, and the D joint pipe 13d is attached to the middle of the cylindrical portion 11 at a position opposite the valve seat 4, which is a refrigerant pipe of this embodiment that opens into the cylindrical portion 11. The E joint pipe 13e, the S joint pipe 13s, and the C joint pipe 13c are attached to the valve seat 4 in a straight line in the axial direction X of the valve housing 1 as refrigerant pipes of this embodiment. The valve body 5 has a bowl-shaped recess 5A formed on its inside. At the end position on the left side of FIG. 1, the valve body 5 connects the S joint pipe 13s and the E joint pipe 13e through the bowl-shaped recess 5A. At this time, the C joint pipe 13c is connected to the D joint pipe 13d mainly through the through hole 3a of the connecting plate 3 in the high pressure chamber 11A. In addition, at the right end position of the valve body 5 in FIG. 1, the S joint pipe 13s and the C joint pipe 13c are connected by the bowl-shaped recess 5A. At this time, the E joint pipe 13e is connected to the D joint pipe 13d mainly through the through hole 3a in the high pressure chamber 11A.

The slide-type switching valve 10 of this embodiment is provided, for example, in a refrigeration cycle (not shown). Note that since a wide variety of general refrigeration cycles can be used as the refrigeration cycle, illustrations of the refrigeration cycle are omitted here for convenience.

In this refrigeration cycle, the D joint pipe 13d is connected to the discharge port of the compressor, and the S joint pipe 13s is connected to the suction port of the compressor. The C joint pipe 13c is connected to the outdoor heat exchanger, and the E joint pipe 13e is connected to the indoor heat exchanger. The outdoor heat exchanger and the indoor heat exchanger are connected via a throttling device. The refrigeration cycle is composed of the path from the C joint pipe 13c to the outdoor heat exchanger, the throttling device, the indoor heat exchanger, and the E joint pipe 13e, and the path from the S joint pipe 13s to the compressor and the D joint pipe 13d. Note that the refrigerant in the refrigeration cycle contains a small amount of refrigeration oil to protect the compressor and other equipment.

The pilot valve is connected to the slide type switching valve 10. The pilot valve has a structure similar to that of the slide type switching valve 10, and switches the flow path by moving the valve body with an electromagnetic actuator or the like. This pilot valve switches the connection destination of the conduit communicating with the S joint pipe 13s of the slide type switching valve 10 connected to the suction port of the compressor between the pressure introduction pipe 14L communicating with the first working chamber 12A on the left side of the slide type switching valve 10 and the pressure introduction pipe 14R communicating with the second working chamber 12B on the right side, and at the same time switches the connection destination of the conduit communicating with the D joint pipe 13d of the slide type switching valve 10 connected to the discharge port of the compressor between the pressure introduction pipe 14R and the pressure introduction pipe 14L. As a result, the pressure difference between the pressure in the first working chamber 12A, to which the suction pressure or discharge pressure of the compressor is introduced, and the pressure in the second working chamber 12B on the opposite side causes the pistons 2L, 2R, connecting plate 3, and valve body 5 to move along the axis X of the valve housing 1, switching the position of the valve body 5 and switching the flow path of the refrigeration cycle.

With the above configuration, the high-pressure refrigerant compressed by the compressor flows into the main valve chamber 11A from the D joint pipe 13d, and in cooling operation, the high-pressure refrigerant flows into the outdoor heat exchanger from the C joint pipe 13c. In addition, in heating operation with the valve body 5 switched, the high-pressure refrigerant flows into the indoor heat exchanger from the E joint pipe 13e. That is, during cooling operation, the refrigerant discharged from the compressor circulates from the C joint pipe 13c → outdoor heat exchanger → throttling device → indoor heat exchanger → E joint pipe 13e, and the outdoor heat exchanger functions as a condenser and the indoor heat exchanger functions as an evaporator to perform cooling. In addition, during heating operation, the refrigerant circulates in the opposite direction, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator to perform heating.

The pistons 2L, 2R of the slide-type switching valve 10 have a mirror-symmetrical structure as shown in Figure 1. Each piston 2L, 2R is equipped with a packing 21, a fixed disk 22 fixed to the connecting plate 3, a leaf spring 23, and a disk-shaped stopper plate 24. The packing 21, fixed disk 22, leaf spring 23, and stopper plate 24 are arranged coaxially around the axis X and fixed together with rivets, and the integrated pistons 2L, 2R are fixed to the connecting plate 3 with bolts.

The following describes the D joint pipe 13d, E joint pipe 13e, S joint pipe 13s, and C joint pipe 13c as joint members that are refrigerant pipes of this embodiment attached to the slide-type switching valve 10 configured as described above. In the following, these D joint pipe 13d, E joint pipe 13e, S joint pipe 13s, and C joint pipe 13c are collectively referred to as joint member 100. In the following, the cases where the connection auxiliary part 200 described later is provided on the inner peripheral surface, the outer peripheral surface, and both the inner peripheral surface and the outer peripheral surface of the joint member 100 are described in order using Figures 2 to 9, 10 to 14, and 15 to 18, respectively.

As shown in Figures 2 and 3, the joint member 100, which is the refrigerant pipe of this embodiment, is made of stainless steel, and is provided with a thin-plate-like connection auxiliary part 200, also called a lining, made of copper or a copper alloy (here, phosphor bronze containing tin) joined by brazing on the inner circumferential surface 100a at at least one longitudinal end. Such a connection auxiliary part 200 is preferably made of a thin-plate-like sheet-like body in the form of strips with a thickness of 0.05 mm to 0.5 mm.

As shown in FIG. 2, the connection auxiliary part 200A is arranged on the inner peripheral surface 100a at one end in the longitudinal direction of the joint member 100 in a state where it is rounded into a C-shape when viewed from a direction perpendicular to the axial direction. At this time, the opposing ends 201 and 202 of the connection auxiliary part 200A may be arranged in abutting contact or spaced apart.

Such a connection auxiliary part 200 is arranged via a molten solidified layer 300 of a brazing material (here, phosphorus bronze containing tin) formed on the inner peripheral surface 100a at one end of the joint member 100, and is firmly joined by brazing after removing the oxide film formed on the surface of the inner peripheral surface 100a of the joint member 100. The oxide film can be removed, for example, using an oxidation-reduction furnace, and brazing can be performed in an environment where the oxide film can be removed. At this time, it is preferable that the thickness of the connection auxiliary part 200 is thinner than the thickness of the joint member 100. This reduces the effects of thermal expansion and thermal contraction in the connection auxiliary part 200, and prevents the connection auxiliary part 200 from peeling off from the joint member 100. In addition, it is preferable that the thickness of the molten solidified layer 300 is thinner than the thickness of the connection auxiliary part 200. This suppresses the variation in the thickness of the molten and solidified layer 300 of the brazing material, and suppresses the variation in the mounting position of the connection auxiliary part 200 relative to the inner circumferential surface 100a of the joint member 100. In addition, it is preferable that the thickness of the molten and solidified layer 300 of the brazing material is 25% or less of the thickness of the connection auxiliary part 200. By making the thickness of the molten and solidified layer 300 of the brazing material 10% or more of the thickness of the connection auxiliary part 200, the strength of the molten and solidified layer 300 can be maintained. The melting point of the connection auxiliary part 200 is higher than the melting point of the molten and solidified layer 300.

The connection auxiliary part 200 is provided over a range that is approximately equal to the length of the other refrigerant pipe 60 (see FIG. 7) to be connected to the joint member 100. In more detail, the connection auxiliary part 200 is provided over a range that satisfies the brazing strength with the refrigerant pipe to be connected to the joint member 100. Specifically, the connection auxiliary part 200 is provided over a range that is at least as long as the thickness of the joint member 100, preferably at least half the inner diameter of the joint member 100, and more preferably at least the inner diameter of the joint member 100, from the end face of the joint member 100 toward the inside in the longitudinal direction.

In the present embodiment, the joint member 100 is formed with a pipe stopper portion 101 that regulates the insertion amount of the other refrigerant pipe to be connected at the portion where the inner end of the connection auxiliary portion 200 in the longitudinal direction is located. At this time, the pipe stopper portion 101 is formed by rolling (inner dowel) so as to protrude inward from the inner peripheral surface 100a of the joint member 100. Note that the pipe stopper portion 101 may be formed so as to protrude outward from the outer peripheral surface 100b of the joint member 100 as shown in FIG. 4. In this case, in other words, the end side where the connection auxiliary portion 200 of the joint member 100 is provided is made larger in diameter than the other portions to form the pipe stopper portion 101. With this configuration, the insertion amount of the refrigerant pipe (joint member) to be connected can be easily regulated, and dripping of the brazing material (here, phosphorus copper brazing not containing tin) used for brazing, which will be described later, can be prevented. In addition, the pipe stopper portion 101 can be formed integrally with the joint member 100, eliminating the need to provide it separately, reducing the number of parts.

The present embodiment as described above has the following advantages. That is, when the joint member 100 itself is made of a material containing stainless steel, a connection auxiliary part 200 made of copper or a copper alloy as a second metal material is provided on the inner peripheral surface 100a. Therefore, as shown in FIG. 7 described later, the refrigerant pipe 60 inserted into the joint member 100 and the joint member 100 can be easily connected by brazing via the connection auxiliary part 200.

In this case, in the joint member 100, the connection auxiliary part 200 made of copper or copper alloy is preferably a thin sheet-like body and is arranged in a rolled C-shape. According to this configuration, when the connection auxiliary part 200 is arranged on the inner peripheral surface at the end of the joint member 100, the connection auxiliary part 200 of the sheet-like body elastically deformed to an inner diameter smaller than the inner diameter of the joint member 100 is held on the inner peripheral surface of the refrigerant pipe by an elastic force for maintaining the shape in the direction of opening from the C-shaped rolled state, and when the connection auxiliary part 200 is arranged on the outer peripheral surface at the end of the refrigerant pipe, the connection auxiliary part 200 plastically deformed to an inner diameter smaller than the outer diameter of the joint member 100 is held on the outer peripheral surface of the refrigerant pipe by an elastic force for maintaining the shape in the direction of rolling into a C-shape, so that the connection auxiliary part 200 can be easily arranged without the trouble of holding it at the arrangement site by, for example, spot welding.

The present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention.

For example, as shown in the second modified example in FIG. 5 and FIG. 6, it is preferable that the flange portion 203 bent radially outward is provided at the portion of the connection auxiliary portion 200 that is disposed at the open end (end surface 100c) of the joint member 100. As a result, when the connection auxiliary portion 200 is disposed at the open end of the joint member 100 in a C-shaped rolled state, the flange portion 203 faces the end surface 100c of the joint member 100, and the connection auxiliary portion 200 can be easily positioned relative to the open end. Furthermore, since a molten and solidified layer 300 of the brazing material is formed between the flange portion 203 and the end surface 100c of the joint member 100, the connection auxiliary portion 200 that extends to the end surface 100c of the joint member 100 can be easily provided, and the reliability of the connection can be more easily ensured.

In this way, in the stainless steel joint member 100 having the thin plate-shaped connection auxiliary part 200 made of phosphor bronze, as shown in Figure 7, even if the refrigerant pipe 60 in the refrigeration cycle (not shown) connected to the inner peripheral surface 100a side of the joint member 100 is made of copper or a copper alloy, it can be easily connected by brazing. The brazing material used to connect the refrigerant pipe 60 to the stainless steel joint member 200 having the connection auxiliary part 200 has a lower melting point (lower solidus temperature) than the brazing material used to join the connection auxiliary part 200 to the joint member 100. For example, phosphorus copper brazing material that does not contain tin as described above is used. At this time, since the connection auxiliary part 200 made of phosphorus bronze having the flange part 203 extending to the end face 100c of the joint member 100 is provided, not only on the surface of the joint member 100 that contacts the outer peripheral surface 60a of the refrigerant pipe 60 (in this case, the inner peripheral surface 100a), but also on the end face 100c of the joint member 100, when the material of the refrigerant pipe 60 is copper or a copper alloy as the second metal material same as that of the connection auxiliary part 200, the first fillet 70 for joining the refrigerant pipe 60 well is easily formed. As a result, the joint is formed without any gaps, and the airtightness of the brazing part can be reliably ensured. Therefore, the reliability of the connection between the joint member 100 and the refrigerant pipe 60 can be further ensured. In addition, the end face 60c side of the refrigerant pipe 60 abuts against the pipe stopper part 101, so that the insertion amount of the refrigerant pipe 60 into the joint member 100 can be easily regulated and the dripping of the brazing material used for brazing can be prevented. Furthermore, when the material of the refrigerant pipe 60 is copper or a copper alloy, which is the same second metal material as the connection auxiliary part 200, the second fillet 80 for joining the refrigerant pipe 60 well between the connection auxiliary part 200 and the end face 60c of the refrigerant pipe 60 is easily formed. This allows joining without gaps, reliably ensuring airtightness of the brazed part, and further improving the reliability of the connection between the joint member 100 and the refrigerant pipe 60.

In the joint member 100, which is the refrigerant pipe of this embodiment, the connection auxiliary part 200A made of copper or a copper alloy forming the connection auxiliary part 200 may be configured as an annular tubular body, as in Modification 3 shown in Figures 8 and 9, in which the same reference numerals are used for parts corresponding to those in Figures 5 and 6. In addition, the connection auxiliary part 200A shown in Figure 9 has a circular cross section, but it may have a substantially polygonal cross section, and the vertices of the substantially polygonal cross section may be pressed into the inner circumferential surface of the joint member 100. As a result, since it is pressed against the inner circumferential surface 100a, it can be easily positioned without the need for spot welding or the like to hold it at the position where it is positioned. In addition, in each of the joint members 100 shown in Figures 2 to 8 above, the pipe stopper part 101 is formed so that its protrusion amount protrudes inward from the inner circumferential surface of the connection auxiliary part 200. In other words, the inner diameter of the pipe stopper part 101 is formed to be smaller than the inner diameter of the connection auxiliary part 200.

So far, the case where the connection auxiliary part 200 is provided on the inner peripheral surface 100a of the joint member 100 has been described, but the connection auxiliary part 200 may be provided on the outer peripheral surface 100b of the joint member 100 as in Modifications 4 and 5 shown in Figures 10 and 11, in which the same reference numerals are used for parts corresponding to those in Figures 2 and 4. In this way, even when the connection auxiliary part 200 is provided on the outer peripheral surface 100b of the joint member 100, the connection auxiliary part 200 is formed over a range that is approximately equal to the length of the joint member 100 inserted into the refrigerant pipe 60 (see Figure 14 described later). In more detail, it is formed over a range that can fully satisfy the brazing strength with the refrigerant pipe connected to the joint member 100, and specifically, it is formed over a range of at least the thickness of the joint member 100 from the end face of the joint member 100, preferably a range of at least half the inner diameter of the joint member 100, and more preferably a range of at least the inner diameter of the joint member 100.

In addition, even when the connection auxiliary part 200 is provided on the outer peripheral surface 100b of the joint member 100, a pipe stopper part 101 that regulates the insertion amount of the other refrigerant pipe to be connected is formed at the part where the inner end part of the connection auxiliary part 200 in the longitudinal direction of the joint member 100 is located, as in the case where it is provided on the inner peripheral surface 100a. In this case, as a modification 4, the pipe stopper part 101 may be formed by bulging (external dowel) to protrude outward from the outer peripheral surface 100b of the joint member 100 (FIG. 10), or as a modification 5, the end side where the connection auxiliary part 200 of the joint member 100 is provided may be formed by reducing the diameter more than other parts to protrude inward from the inner peripheral surface 100a of the joint member 100 (FIGS. 11 and 12). With such a configuration, the insertion amount of the refrigerant pipe (joint member) to be connected can be easily regulated and dripping of the brazing material used for brazing can be prevented. In addition, since the pipe stopper portion 101 can be formed integrally with the joint member 100, there is no need to provide the pipe stopper portion 101 separately, and the number of parts can be reduced.

In addition, in this case, as in the sixth modified example shown in FIG. 13, it is preferable that the flange portion 203 bent radially inward is provided at the portion of the connection auxiliary portion 200 that is disposed at the open end (end surface 100c) of the joint member 100. As a result, when the connection auxiliary portion 200 is disposed at the open end of the joint member 100 in a C-shaped state, the flange portion 203 faces the end surface 100c of the joint member 100, and the connection auxiliary portion 200 can be easily positioned relative to the open end. Furthermore, since a molten and solidified layer 300 of the brazing material is formed between the flange portion 203 and the end surface 100c of the joint member 100, the connection auxiliary portion 200 that extends to the end surface 100c of the joint member 100 can be easily provided, and the reliability of the connection can be more easily ensured.

In the joint member 100 having the connection auxiliary part 200 joined by brazing as described above, as shown in FIG. 14 in which the same reference numerals are used for parts corresponding to those in FIG. 7, even if the refrigerant pipe 60 connected to the outer peripheral surface 100b side of the joint member 100 is made of copper or a copper alloy, it can be easily connected by brazing. At this time, since the connection auxiliary part 200 of phosphorus bronze having the flange part 203 extending to the end face 100c of the joint member 100 is provided, not only the surface of the joint member 100 that contacts the inner peripheral surface 60b of the refrigerant pipe 60 (in this case, the outer peripheral surface 100b) but also the surface of the joint member 100 that contacts the inner peripheral surface 60b of the refrigerant pipe 60 is provided, when the material of the refrigerant pipe 60 is the same copper or copper alloy as the connection auxiliary part 200, the first fillet 70 for joining the refrigerant pipe 60 well is easily formed. As a result, the joint is made without any gaps, and the airtightness of the brazed part can be reliably ensured. Therefore, the reliability of the connection between the joint member 100 and the refrigerant pipe 60 can be further improved. In addition, the end surface 60c of the refrigerant pipe 60 abuts against the pipe stopper portion 101, which makes it easy to regulate the amount of insertion of the refrigerant pipe 60 into the joint member 100 and prevents dripping of the brazing material used in brazing. Furthermore, if the material of the refrigerant pipe 60 is the same copper or copper alloy as the connection auxiliary portion 200, the second fillet 80 for joining the refrigerant pipe 60 well between the connection auxiliary portion 200 and the end surface 60c of the refrigerant pipe 60 is also easily formed. This allows for a gap-free joining, reliably ensuring airtightness of the brazing portion, and further improving the reliability of the connection between the joint member 100 and the refrigerant pipe 60.

Next, a case will be described in which the connection auxiliary part 200 is provided on both the inner peripheral surface 100a and the outer peripheral surface 100b of the joint member 100. As shown in Modifications 7 and 8 in Figs. 15 and 16, in which the same reference numerals are used for parts corresponding to Figs. 2 and 4, the connection auxiliary part 200 may have a U-shaped cross section, and one end of the joint member 100 may be inserted into the inner peripheral side of the U-shape from the end face 100c. In this case, the connection auxiliary part 200 is provided from the inner peripheral surface 100a of the joint member 100 through the end face 100c to the outer peripheral surface 100b.

In this way, even when the connection auxiliary part 200 is provided from the inner peripheral surface 100a to the outer peripheral surface 100b of the joint member 100, the connection auxiliary part 200 is formed over a range approximately equal to the length of the joint member 100 inserted into the refrigerant pipe 60 (see Figures 7 and 14). In more detail, it is formed over a range that satisfies the brazing strength with the refrigerant pipe connected to the joint member 100, specifically, it is formed over a range of at least a thickness of the joint member 100 from the end face of the joint member 100, preferably a range of a length of at least half the inner diameter of the joint member 100, and more preferably a range of a length of at least the inner diameter of the joint member 100. Also, in the joint member 100 shown in Figures 10 to 14 above, the pipe stopper part 101 is formed so that its protrusion amount protrudes outward from the outer peripheral surface of the connection auxiliary part 200. In other words, it is formed so that the outer diameter of the pipe stopper part 101 is larger than the outer diameter of the connection auxiliary part 200. On the other hand, in the joint member 100 shown in Figures 15 and 16, the pipe stopper portion 101 is formed so that its protrusion amount protrudes inward from the inner peripheral surface of the connection auxiliary portion 200. In other words, the inner diameter of the pipe stopper portion 101 is formed so that it is smaller than the inner diameter of the connection auxiliary portion 200.

With this configuration, it is possible to easily provide a connection auxiliary part 200 that covers not only both the outer peripheral surface 100b and the inner peripheral surface 100a at the end of the joint member 100, but also the end surface 100c of the joint member 100 as a whole. This makes it easier to form a good fillet when the material of the connection object is the same copper or copper alloy as the connection auxiliary part 200. This allows the joint member 100 and the connection object to be joined without any gaps, reliably ensuring airtightness of the brazed area, and easily realizing a configuration that can further ensure the reliability of the connection.

Up to this point, we have described a case where the pipe stopper portion 101 that regulates the insertion amount of the other refrigerant pipe to be connected is formed at the location where the inner end of the connection auxiliary portion 200 in the longitudinal direction of the joint member 100 is located, but the present invention is not limited to this. That is, as shown in Modifications 9 and 10 in Figs. 17 and 18, a pipe stopper portion 205 that regulates the insertion amount of the other refrigerant pipe to be connected may be formed at the inner end of the connection auxiliary portion 200 in the longitudinal direction when it is provided on the joint member 100. With this configuration, the insertion amount of the refrigerant pipe (joint member) to be connected can be easily regulated and dripping of the brazing material used for brazing can be prevented.

In this case, it is preferable that the pipe stopper portion 205 protrudes outward from the outer peripheral surface 100b of the connection auxiliary portion 200, inward from the inner peripheral surface 100a, or both. With this configuration, the pipe stopper portion 205 can be formed integrally with the connection auxiliary portion 200, so there is no need to provide the pipe stopper portion 205 separately from the connection auxiliary portion 200, and the number of parts can be reduced.

In this embodiment, the case where the joint member 100, which is a refrigerant pipe, is connected to the copper or copper alloy refrigerant pipe 60 of the refrigeration cycle is described, but the connection target of the joint member 100 is not limited to a copper or copper alloy refrigerant pipe, but may be a metal pipe or joint member such as stainless steel or iron having a copper or copper alloy connection auxiliary part 200 on the inner circumferential surface, outer circumferential surface, or both of the connection side end like the joint member 100. The material of the refrigerant pipe having the connection auxiliary part 200 is preferably a metal having a higher melting point than copper or copper alloy. In addition, in this embodiment, the case where the connection auxiliary part 200 provided on the joint member 100, which is a refrigerant pipe, is made of copper or copper alloy has been described, but the material (second metal material) of the connection auxiliary part 200 may be the same or equivalent to the material (second metal material) of the refrigerant pipe 60. For example, if the material of the refrigerant pipe 60 is aluminum (second metal material), a connection auxiliary part made of aluminum (second metal material) may be provided on the stainless steel refrigerant pipe 60. In other words, the material used for the joint member 100 should be the same as the material used for the surface of the refrigerant pipe 60 on the side facing the joint member 100.

The connection structure of the refrigerant piping (coupling member 100) described above is a connection structure of the coupling member 100 in which the coupling member 100 (first refrigerant piping) and the refrigerant piping 60 (second refrigerant piping) are connected by brazing, and the stainless steel coupling member 100 is provided with a copper or copper alloy connection auxiliary part 200 joined by brazing to the inner surface 100a (or outer surface 100b) of the refrigerant piping 60 side end, and it is preferable that the refrigerant piping 60 is made of copper or copper alloy (or has a copper or copper alloy connection auxiliary part 200 joined by brazing to the outer surface 100b or inner surface 100a of the coupling member 100 side end). According to this connection structure of the joint member 100, even if the joint member 100 (first refrigerant piping) is made of stainless steel, it has a copper or copper alloy connection auxiliary part 200 brazed to the inner surface 100a or outer surface 100b of the refrigerant piping 60 (second refrigerant piping) side end, so it can be easily connected to the second refrigerant piping to be connected, which is made of copper or copper alloy, or has a copper or copper alloy connection auxiliary part brazed to the outer surface 60a or inner surface 60b of the first refrigerant piping side end.

The above-described slide-type switching valve 10 as a valve device is a valve device in which a coupling member 11 is connected to a valve housing 1 as a valve body, and it is preferable that any of the above-described refrigerant piping (coupling member 100) is used as the coupling member. According to this slide-type switching valve 10, even if the coupling member 100 is made of stainless steel, as with the above-described coupling member 100, the connection side end of the coupling member 100 is provided with a brazed copper or copper alloy connection auxiliary part 200 on its inner circumferential surface 100a or outer circumferential surface 100b, so that it can be easily connected to the refrigerant piping to be connected by brazing. In addition, the same effects as those of each of the above-described coupling members 100 can be obtained.

Although the best configurations and methods for implementing the present invention are disclosed in the above description, the present invention is not limited thereto. That is, the present invention is mainly illustrated and described with respect to a specific embodiment, but does not deviate from the scope of the technical idea and purpose of the present invention. For example, in the above embodiment, the refrigerant piping of the present invention is applied to a slide-type switching valve, but the refrigerant piping of the present invention is not limited to slide-type switching valves, and can be applied to various valve devices such as motor valves, solenoid valves, and check valves, as well as various devices such as heat exchangers, accumulators, oil separators, and compressors. In addition, those skilled in the art can make various modifications to the above-described embodiments in terms of shape, material, quantity, and other detailed configurations. Therefore, the descriptions that limit the shapes, materials, etc. disclosed above are illustrative descriptions to facilitate understanding of the present invention, and do not limit the present invention, so descriptions of the names of components that remove some or all of the limitations on the shapes, materials, etc. are included in the present invention.

1 Valve housing (valve body)
11 Cylindrical portion 12 Cap portion 2 Piston 21 Gasket 22 Fixed disk 23 Leaf spring 3 Connecting plate 4 Valve seat 5 Valve body 10 Slide type switching valve 100 Joint member (refrigerant pipe, first refrigerant pipe)
100a Inner peripheral surface 100b Outer peripheral surface 100c End surface 101 Pipe stopper portion 200 Connection auxiliary portion 201 End portion 202 End portion 203 Flange portion 205 Pipe stopper portion 300 Melted solidified layer 60 Refrigerant pipe (second refrigerant pipe)
60a: outer peripheral surface; 60b: inner peripheral surface; 60c: end surface; 70: first fillet; 80: second fillet

Claims (18)

A refrigerant pipe made of stainless steel,
A thin plate-like connection auxiliary part made of copper or a copper alloy is provided on an inner peripheral surface, an outer peripheral surface, or both of them at least at one end in the longitudinal direction,
a molten and solidified layer of the brazing material is formed between the inner circumferential surface, the outer circumferential surface, or both of these surfaces and the connection auxiliary portion;
The refrigerant pipe, wherein the connection auxiliary portion is arranged by being pressed against an inner circumferential surface, an outer circumferential surface, or both of the inner circumferential surface and the outer circumferential surface of the refrigerant pipe via the molten and solidified layer . The refrigerant pipe according to claim 1, wherein the connection auxiliary part is arranged in a rolled C-shape when viewed from a direction perpendicular to the axial direction. The refrigerant piping according to claim 1, wherein the connection auxiliary part is an annular cylindrical body. The refrigerant pipe according to claim 1, wherein the connection auxiliary part extends to the end face at the one end. The refrigerant pipe according to claim 4 , wherein the connection auxiliary portion has a flange portion facing the end face, and a molten and solidified layer of brazing material is formed between the flange portion and the end face. Refrigerant piping according to claim 1, in which the connection auxiliary part has a U-shaped cross section, and the one end is inserted into the inner periphery of the U-shape. The refrigerant pipe according to claim 1, wherein a pipe stopper portion is formed at a portion where the inner end portion of the connection auxiliary portion is located in the longitudinal direction of the refrigerant pipe, to regulate the insertion amount of another refrigerant pipe to be connected. The refrigerant pipe according to claim 7 , wherein the pipe stopper portion protrudes outward from an outer circumferential surface of the refrigerant pipe or protrudes inward from an inner circumferential surface of the refrigerant pipe. The refrigerant pipe according to claim 1, wherein a pipe stopper portion is formed on the inner end portion of the connection auxiliary portion in the longitudinal direction when the connection auxiliary portion is attached to the refrigerant pipe, to regulate the insertion amount of another refrigerant pipe to be connected. The refrigerant pipe according to claim 9 , wherein the pipe stopper portion protrudes outward from an outer circumferential surface of the connection auxiliary portion, inward from an inner circumferential surface of the connection auxiliary portion, or both. The refrigerant pipe according to claim 1, wherein the thickness of the connection auxiliary part is thinner than the thickness of the refrigerant pipe. The refrigerant pipe according to claim 1, wherein the thickness of the melted and solidified layer is thinner than the thickness of the connection auxiliary part. A refrigerant piping connection structure in which a first refrigerant piping and a second refrigerant piping are connected by brazing,
the first refrigerant pipe is made of stainless steel, and a thin-plate-shaped connection auxiliary part made of a second metal material different from stainless steel is joined to an inner circumferential surface, an outer circumferential surface, or both of the surfaces of the end part of the second refrigerant pipe via a molten and solidified layer of a brazing material, and the connection auxiliary part is arranged by being pressed against the inner circumferential surface, the outer circumferential surface, or both of the surfaces of the first refrigerant pipe via the molten and solidified layer;
The second refrigerant piping is made of the second metallic material, or a thin-plate connection auxiliary part made of the second metallic material is joined to an outer peripheral surface, an inner peripheral surface, or both of the first refrigerant piping end portion via a molten and solidified layer of the brazing material , and the connection auxiliary part is positioned by being pressed against the inner peripheral surface, the outer peripheral surface, or both of the second refrigerant piping via the molten and solidified layer . The connection auxiliary portion of the first refrigerant pipe is formed to extend to an end surface of the first refrigerant pipe at an end portion of the first refrigerant pipe on the second refrigerant pipe side,
The refrigerant piping connection structure according to claim 13 , wherein when the second refrigerant piping is not made of the second metallic material, the connection auxiliary portion is formed to extend to an end face of the second refrigerant piping at an end portion on the first refrigerant piping side. The refrigerant pipe connection structure according to claim 14 , wherein the connection auxiliary portion has a flange portion facing the end face, and a molten and solidified layer of brazing material is formed between the flange portion and the end face. The refrigerant pipe connection structure according to claim 13 , wherein the connection auxiliary portion has a thickness smaller than a thickness of the first refrigerant pipe. The refrigerant pipe connection structure according to claim 13 , wherein the melted and solidified layer has a thickness smaller than a thickness of the connection auxiliary portion. A valve device in which a coupling member is connected to a valve body,
A valve device, comprising the refrigerant pipe according to any one of claims 1 to 12 as the joint member.

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