JP2024124830A - Brazed structure, heat exchanger, and brazing method - Google Patents

Abstract

To make a fluid circulating in a pipe less likely to leak from a space between a boss part and the pipe.SOLUTION: A brazing structure 10 includes: a cylindrical boss part 20; and a refrigerant pipe 30 which extends in a predetermined direction and is inserted into the boss part 20 from the predetermined direction and provided with a recessed part 31 recessed from an outer peripheral surface. In the boss part 20 and the refrigerant pipe 30, an area including the recessed part 31 on the outer peripheral surface of the refrigerant pipe 30 and an inner peripheral surface of the boss part 20 are brazed with a brazing material 40.SELECTED DRAWING: Figure 2

Description

This disclosure relates to a brazing structure, a heat exchanger, and a brazing method.

Plate heat exchangers are known as heat exchangers that involve a phase change of a fluid, such as an evaporator or a condenser (see, for example, Patent Document 1). A plate heat exchanger heats or cools a fluid by exchanging heat between a fluid flowing between one of a pair of plates arranged side by side and a fluid flowing between the other plate.
Patent Document 1 discloses a plate heat exchanger in which flow paths for a first fluid and separate flow paths for a second fluid are arranged alternately, and heat exchange is performed between the two fluids.

JP 2019-184133 A

Such a plate heat exchanger is provided with a boss at the connection portion with a pipe that supplies a fluid to the heat exchanger. The pipe is attached to the heat exchanger by inserting the pipe into the boss and connecting the boss to the pipe.
As a method for connecting the boss portion and the pipe, it is possible to supply a brazing material into a gap formed between the boss portion and the pipe to braze the boss portion and the pipe. However, when the boss portion and the pipe are made of different materials, the member with the larger heat capacity may not be heated sufficiently due to the difference in heat capacity between the boss portion and the pipe. Therefore, the fluidity of the brazing material flowing through the gap may be poor, and the brazing material may not penetrate sufficiently into the gap. If the brazing material does not penetrate sufficiently into the gap, the boss portion and the pipe may not be brazed properly, and fluid may leak from between the boss portion and the pipe.

The present disclosure has been made in consideration of these circumstances, and aims to provide a brazing structure, a heat exchanger, and a brazing method that can prevent the fluid flowing inside the pipe from leaking between the boss portion and the pipe.

In order to solve the above problems, the brazing structure, heat exchanger, and brazing method disclosed herein employ the following measures.
A brazing structure according to one aspect of the present disclosure comprises a cylindrical boss portion, and a pipe extending in a predetermined direction, inserted into the boss portion, and having a recess formed therein that is recessed from an outer surface, wherein the boss portion and the pipe are brazed to each other at an area of the outer surface of the pipe that includes the recess and an inner surface of the boss portion.

A brazing method according to one aspect of the present disclosure is a method for brazing a cylindrical boss portion to a pipe inserted into the boss portion, and includes a recess forming process for forming a recess in the outer surface of the pipe, and a brazing process for brazing an area of the outer surface of the pipe that includes the recess to the inner surface of the boss portion.

This disclosure makes it possible to prevent fluid flowing inside the pipe from leaking between the boss portion and the pipe.

FIG. 2 is a perspective exploded view illustrating a heat exchanger according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a boss portion and a refrigerant pipe according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing a refrigerant pipe according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a main portion of a refrigerant pipe according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a boss portion and a refrigerant pipe according to an embodiment of the present disclosure. FIG. 11 is a cross-sectional view showing a boss portion and a refrigerant pipe according to a modified example of the embodiment of the present disclosure.

Hereinafter, an embodiment of a brazing structure, a heat exchanger, and a brazing method according to the present disclosure will be described with reference to the drawings.
The heat exchanger according to the present embodiment is a so-called plate fin heat exchanger. The heat exchanger 1 is used as a condenser or an evaporator of a refrigerator such as a turbo refrigerator. As shown in FIG. 1, the heat exchanger 1 has a plurality of first plates 2a and second plates 2b arranged alternately at a predetermined interval in a predetermined direction. The adjacent first plates 2a and second plates 2b are joined together. The heat exchanger 1 has a plurality of flow paths (first flow paths 8 and second flow paths 9) through which a fluid flows between the first plates 2a and the second plates 2b. The first flow paths 8 and the second flow paths 9 are arranged alternately in a predetermined direction. That is, the first flow paths 8 and the second flow paths 9 are adjacent to each other in a predetermined direction and are separated by the first plate 2a or the second plate 2b.

The first plate 2a, which is located at one end in the predetermined direction, has a first inlet side boss 3a and a second outlet side boss 3c at its upper end. The first plate 2a has a second inlet side boss 3b and a first outlet side boss (not shown) at its lower end. A cover plate 4 is attached to the first plate 2a, which is located at the other end in the predetermined direction.

Inner fins 5a and 5b are provided on the surfaces of the first plate 2a and the second plate 2b facing the cover plate 4, respectively. The inner fin 5a is disposed in the first flow path 8. The inner fin 5b is disposed in the second flow path 9.

A first fluid 6 (e.g., a fluid with a high temperature) flows into each first flow path 8 via the first inlet side boss portion 3a. A second fluid 7 (e.g., a fluid with a lower temperature than the first fluid 6) flows into each second flow path 9 via the second inlet side boss portion 3b. In the heat exchanger 1, heat exchange takes place between the first fluid 6 flowing through the first flow path 8 and the second fluid 7 flowing through the second flow path 9.

The first fluid 6 flowing through each first flow passage 8 flows downward while being cooled by heat exchange with the second fluid 7. The first fluid 6 having flowed through the first flow passage 8 is discharged from the heat exchanger 1 via the first outlet side boss portion.
The second fluid 7 flowing through each second flow passage 9 flows upward while being heated by heat exchange with the first fluid 6. The second fluid 7 having flowed through the second flow passage 9 is discharged from the heat exchanger 1 via the second outlet side boss portion 3c.

In this embodiment, refrigerant pipes 30 (see FIG. 2) are inserted into the first inlet side boss portion 3a, the first outlet side boss portion, the second inlet side boss portion 3b, and the second outlet side boss portion 3c. Note that, for convenience of illustration, the refrigerant pipes 30 are omitted in FIG. 1.
The following describes in detail the brazed structure 10 between each boss portion and the refrigerant pipe 30. In the following description, the first inlet side boss portion 3a, the first outlet side boss portion, the second inlet side boss portion 3b, and the second outlet side boss portion 3c will be collectively referred to as "boss portion 20" when there is no need to distinguish between them.
In the following description, in a predetermined direction, the side closer to the heat exchanger 1 (the lower side in FIG. 2, etc.) is referred to as one side, and the side farther from the heat exchanger 1 (the upper side in FIG. 2, etc.) is referred to as the other side. The end on one side is referred to as one end. The end on the other side is referred to as the other end. With regard to the boss portion 20, the end on one side may be referred to as the base end, and the end on the other side may be referred to as the tip end.

As shown in FIG. 2, the brazing structure 10 has a boss portion 20, a refrigerant pipe 30, and a brazing material 40. The brazing material 40 is a silver brazing material made of a material containing silver.

The boss portion 20 is attached to the first plate (attached member) 2a of the heat exchanger 1. The boss portion 20 (first inlet side boss portion 3a, etc.) is a cylindrical member. The boss portion 20 extends in a predetermined direction around a central axis C that extends in a predetermined direction. The refrigerant pipe 30 is inserted into the boss portion 20. The boss portion 20 and the refrigerant pipe 30 are brazed with brazing material 40.

The boss portion 20 integrally has an insertion portion 21 into which the refrigerant pipe 30 is inserted, and a fixing portion 22 that is fixed to the first plate 2a of the heat exchanger 1. The boss portion 20 is formed of a material that has a larger heat capacity than the refrigerant pipe 30. The boss portion 20 is formed of, for example, stainless steel. Note that the material of the boss portion 20 is not limited to stainless steel. For example, the boss portion 20 may be formed of another metal (for example, brass, etc.).

The insertion portion 21 is a cylindrical member extending about the central axis C. The inner diameter of the insertion portion 21 is larger than the outer diameter of the refrigerant pipe 30. The outer diameter of the insertion portion 21 is smaller than the outer diameter of the fixing portion 22.

The fixed portion 22 is connected to one end of the insertion portion 21 .
The fixed portion 22 is a cylindrical member extending about a central axis C. A step 23 is formed on the inner peripheral surface of the fixed portion 22 so that the inner diameter of one side is smaller.
The fixing portion 22 has an inner diameter that is substantially the same as the inner diameter of the insertion portion 21 on the other side of the step portion 23. The fixing portion 22 is provided such that the inner circumferential surface on the other side of the step portion 23 is flush with the inner circumferential surface of the insertion portion 21.
The inner diameter of the step 23 is smaller than the outer diameter of the refrigerant pipe 30. The other surface of the step 23 abuts against one end of the refrigerant pipe 30.

The refrigerant pipe 30 is inserted into the boss portion 20. The refrigerant pipe 30 extends in a predetermined direction. Refrigerant discharged from a compressor and an expansion valve provided in the refrigerant circuit flows through the inside of the refrigerant pipe 30. The refrigerant pipe 30 supplies refrigerant to the flow paths (first flow path 8 and second flow path 9) provided in the heat exchanger 1 via the boss portion 20, and the refrigerant is discharged from the flow paths.

The refrigerant pipe 30 is formed of a material with a different heat capacity than the boss portion 20. In particular, the refrigerant pipe 30 is formed of a material with a smaller heat capacity than the boss portion 20. The refrigerant pipe 30 is formed of, for example, copper. Note that the material of the refrigerant pipe 30 is not limited to copper. For example, the refrigerant pipe 30 may be formed of another metal.

The refrigerant pipe 30 has a recess 31 formed therein.
As shown in Fig. 3, the recess 31 is formed over the entire circumferential area of the refrigerant pipe 30. As shown in Fig. 2, when one end (lower end in Fig. 2) of the refrigerant pipe 30 abuts against the step 23, the recess 31 is located at the same position in a predetermined direction (vertical direction in Fig. 2) as the other end (upper end in Fig. 2) of the boss portion 20. In detail, the center of the recess 31 in the predetermined direction is located at the same position in the predetermined direction as the other end of the boss portion 20. (See dashed line A). That is, the length from one end of the refrigerant pipe 30 (the portion abutting against the step 23) to the center of the recess 31 is approximately the same as the length from the other end of the step 23 to the other end of the boss portion 20. The relative positions of the recess 31 and the boss portion 20 are not limited to the positions described above. The relative positions of the recess 31 and the boss portion 20 need only be such that the deepest part of the recess 31 (in this embodiment, the flat portion 31c (see Figure 3) described below) and the other end of the boss portion 20 are in the same position in a specified direction.

As shown in FIG. 3, the recess 31 has a first inclined portion 31a at one end in a predetermined direction, which is inclined so that the depth becomes shallower toward the one end. The recess 31 also has a second inclined portion 31b at the other end in the predetermined direction, which is inclined so that the depth becomes shallower toward the other end. The recess 31 also has a flat portion 31c that connects the other end of the first inclined portion 31a to one end of the second inclined portion 31b. The flat portion 31c is provided in the deepest part of the recess 31, and is a cylindrical surface that is approximately parallel to the outer circumferential surface of the refrigerant pipe 30.

The outer diameter and inner diameter of the refrigerant pipe 30 are smaller in the recess 31 than in other regions. The wall thickness t (see FIG. 4) of the refrigerant pipe 30 in the recess 31 is approximately the same as in other regions.

In this embodiment, the refrigerant pipe 30 with the recess 31 is manufactured by forming the recess 31 in a pipe having a uniform inner diameter and outer diameter. The recess 31 is formed, for example, by performing a drawing process on a part of the pipe having a uniform inner diameter and outer diameter.

As shown in FIG. 4, the depth d of the deepest part of the recess 31 is set to a depth at which the following formula (1) is satisfied.

d=C√(t)...(1)
Where, C: Recess depth coefficient
t: thickness of the refrigerant pipe 30 √(t): square root of t

Here, 0.01≦C≦0.25 is set, and the length of the gap formed between the inner peripheral surface of the boss portion 20 and the outer peripheral surface of the flat portion 31c (see FIG. 3), which is the deepest part of the recess 31, satisfies a predetermined standard (for example, the exemplary standard related to the Refrigeration Safety Regulations). That is, the depth d of the recess 31 is set to be 0.01 times or more the root value of the thickness t of the refrigerant pipe 30 (the square root value of t) and 0.25 times or less the root value of the thickness t of the refrigerant pipe 30 (the square root value of t).
By setting the range in this way, the length of the gap formed between the surface of the deepest part of the recess 31 and the outer peripheral surface of the refrigerant pipe 30 can be set to a length that satisfies the above-mentioned specified standard, assuming a typical thickness of the refrigerant pipe.

As shown in FIG. 4, the solder depth l of the recess 31 is set to a solder depth at which the following formula (2) is satisfied.

l ≧ t (2)
where t is the thickness of the refrigerant pipe 30

In general, it is considered that there is no problem in terms of strength if the brazing material 40 penetrates twice the thickness t of the refrigerant pipe 30. If the brazing depth l is set to be equal to or greater than the thickness t of the refrigerant pipe 30 as in formula (2), the length L in a specified direction of the recess 31, which is set to be twice the length of the brazing depth l, can be set to be equal to or greater than twice the thickness t of the refrigerant pipe 30. Therefore, the brazing material 40 can be sufficiently penetrated into the gap formed between the inner surface of the boss portion 20 and the outer surface of the refrigerant pipe 30, so that the joining strength between the boss portion 20 and the refrigerant pipe 30 can be sufficiently ensured.

Next, a method of connecting the boss portion 20 and the refrigerant pipe 30 will be described.
In this embodiment, the boss portion 20 and the refrigerant pipe 30 are connected by brazing.
First, the refrigerant pipe 30 is inserted in a predetermined direction into the boss portion 20. At this time, the refrigerant pipe 30 is inserted until the step portion 23 comes into contact with one end of the refrigerant pipe 30. When the step portion 23 comes into contact with the refrigerant pipe 30, the flat portion 31c of the recess 31 is positioned at the same position as the other end of the boss portion 20 in the predetermined direction.
With the step portion 23 and the refrigerant pipe 30 in contact with each other, molten brazing material 40 is supplied into the gap between the inner peripheral surface of the boss portion 20 and the outer peripheral surface of the refrigerant pipe 30, and the brazing material 40 is also supplied between the other end face of the boss portion 20 and the refrigerant pipe 30. In this way, the boss portion 20 and the refrigerant pipe 30 are brazed in a region including the recessed portion 31.
When the brazing material 40 cools and hardens, the boss portion 20 and the refrigerant pipe 30 are connected.

According to this embodiment, the following advantageous effects are obtained.
In this embodiment, a recess 31 recessed from the outer circumferential surface is formed. As a result, the flow path of the brazing material 40 is wider in the gap formed between the outer circumferential surface of the refrigerant pipe 30 and the inner circumferential surface of the boss portion 20 than when the recess 31 is not formed. Therefore, the brazing material 40 can easily flow in the gap, and the brazing material 40 can easily penetrate into the gap. Therefore, the brazing of the boss portion 20 and the refrigerant pipe 30 can be appropriately performed. Therefore, the joining strength between the boss portion 20 and the refrigerant pipe 30 can be improved. The fluid flowing inside the refrigerant pipe 30 can be made less likely to leak from between the boss portion 20 and the refrigerant pipe 30.

In particular, when a narrow-mouthed pipe with a small outer diameter is used as the refrigerant pipe 30, the gap between the boss portion 20 and the refrigerant pipe 30 is smaller than in the case of a wide-mouthed pipe due to standards (example standards related to Refrigeration Safety Regulations), so the brazing material 40 tends to be less likely to penetrate into the gap. Therefore, when a narrow-mouthed pipe with a small outer diameter is used as the refrigerant pipe 30 (for example, the outer diameter of the refrigerant pipe 30 is 20 mm or less), it is more effective to apply the brazing structure 10 of the present disclosure.

In addition, in this embodiment, the recess 31 is formed over the entire circumferential area of the refrigerant pipe 30. This allows the brazing material 40 to easily penetrate the entire circumference of the refrigerant pipe 30. This allows the boss portion 20 and the refrigerant pipe 30 to be brazed more appropriately. This improves the joint strength between the boss portion 20 and the refrigerant pipe 30.

In addition, in this embodiment, the recess 31 is positioned so as to be at the same position in a predetermined direction as the tip of the boss portion 20. As a result, the gap between the boss portion 20 and the refrigerant pipe 30 is larger at the tip portion of the boss portion 20 than at the base end portion of the boss portion 20. When the brazing material 40 flows into the gap, it flows in from the tip of the boss portion 20. Therefore, by making the gap at the tip portion larger, it is possible to make it easier for the brazing material 40 to flow into the gap.

In addition, in this embodiment, the brazing material 40 can be easily introduced into the recess 31. The brazing material 40 that has flowed into the recess 31 accumulates in the recess 31. This makes it easier for the brazing material 40 to spread in the circumferential direction in the recess 31. The brazing material 40 that has accumulated in the recess 31 then flows (permeates) toward the base end side of the recess 31. In this way, the brazing material 40 that permeates the gap can be made uniform in the circumferential direction, so that the boss portion 20 and the refrigerant pipe 30 can be appropriately brazed. Therefore, the joint strength between the boss portion 20 and the refrigerant pipe 30 can be improved.

In this embodiment, the thickness of the refrigerant pipe 30 does not change at the recess 31, so the decrease in the pressure resistance of the refrigerant pipe 30 can be suppressed.

In addition, in this embodiment, a recess 31 is formed around the entire circumference of the refrigerant pipe 30. As a result, even when the refrigerant pipe 30 is inserted into the boss portion 20 so that the central axis of the refrigerant pipe 30 is inclined relative to the central axis of the boss portion 20 as shown in FIG. 5, the refrigerant pipe 30 and the other end of the boss portion 20 are unlikely to come into contact with each other. Therefore, the brazing material 40 can be more easily permeated into the one end side (see the dashed circle in FIG. 5) of the boss portion 20 than into the other end. Therefore, the brazing material 40 can be permeated over the entire circumferential area. Also, for example, even if the refrigerant pipe 30 is distorted, the brazing material 40 can be permeated, and the brazing material 40 can be permeated over the entire circumferential area, since the refrigerant pipe 30 and the other end of the boss portion 20 are unlikely to come into contact with each other.

[Modifications]
Next, a modified example of this embodiment will be described with reference to Fig. 6. In the above embodiment, an example in which the recess 31 is formed by drawing the refrigerant pipe 30 has been described, but the present disclosure is not limited thereto. For example, as shown in this modified example, the recess may be formed by cutting the outer circumferential surface of the refrigerant pipe 30.

The recess 51 in this modified example is formed over the entire circumferential area. As shown in FIG. 6, when one end of the refrigerant pipe 30 is in contact with the step 23, the center of the recess 51 in a predetermined direction is at the same position in the predetermined direction as the other end of the boss 20 (see dashed line A). The depth of the recess 51 is uniform in the predetermined direction. Note that the relative positions of the recess 51 and the boss 20 are only examples, and are not limited to the relative positions described above. The relative positions of the recess 51 and the boss 20 may be any position in the predetermined direction of the recess 51 and the other end of the boss 20, as long as the position is the same in the predetermined direction.

The outer diameter of the refrigerant pipe 30 is smaller in the recess 51 than in other regions. The inner diameter of the refrigerant pipe 30 is the same in the recess 51 as in other regions. That is, the wall thickness t of the refrigerant pipe 30 is thinner in the recess 51 than in other regions. Therefore, when forming the recess 51 of this modified example, the wall thickness t of the entire pipe may be made thicker than when forming the recess 31 of the above embodiment in order to ensure that the wall thickness t in the recess 51 is a predetermined thickness.

According to this modified example, the recess 51 can be formed simply by machining the outer circumferential surface of the refrigerant pipe 30. The inner diameter of the recess 51 does not change, so the pressure loss of the refrigerant flowing inside the refrigerant pipe 30 can be reduced.

The present disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present disclosure.
For example, in the above embodiment, an example in which the brazing structure 10 is applied to a plate-fin type heat exchanger has been described, but the present disclosure is not limited thereto. For example, the brazing structure 10 of the present disclosure is applicable to any structure in which members having different thermal capacities are brazed together, and the brazing structure 10 may be applied to other types of heat exchangers (such as fin-and-tube type heat exchangers).

The brazing structure, the heat exchanger, and the brazing method according to the above-described embodiments can be understood, for example, as follows.
The brazed structure according to the first aspect of the present disclosure comprises a cylindrical boss portion (20) and a pipe (30) extending in a predetermined direction, inserted into the boss portion, and having a recess (31) recessed from its outer surface, wherein the boss portion and the pipe are brazed to each other at an area of the outer surface of the pipe that includes the recess and an inner surface of the boss portion.

In the above configuration, a recess is formed that is recessed from the outer surface. This makes the flow path of the brazing material wider in the gap formed between the outer surface of the pipe and the inner surface of the boss portion compared to when no recess is formed. Therefore, the brazing material flows more easily in the gap, and the brazing material easily penetrates into the gap. This allows the boss portion and the pipe to be brazed appropriately. This improves the bonding strength between the boss portion and the pipe. It makes it difficult for the fluid flowing inside the pipe to leak from between the boss portion and the pipe.

In addition, in the brazing structure according to the second aspect of the present disclosure, in the first aspect, the recess is formed over the entire circumferential area of the pipe.

In the above configuration, the recess is formed over the entire circumferential area of the pipe. This allows the brazing material to easily penetrate the entire circumference of the pipe. This allows the boss portion and the pipe to be brazed more appropriately. This improves the joint strength between the boss portion and the pipe.

In addition, in the brazed structure according to the third aspect of the present disclosure, in the first or second aspect, the base end of the boss portion is attached to the mounting member (2a), and the boss portion and the piping are arranged so that the recess and the tip of the boss portion are in the same position in a predetermined direction.

In the above configuration, the recess is positioned so that it is at the same position in a specified direction as the tip of the boss. This makes the gap between the boss and the piping larger at the tip of the boss than at the base of the boss. When the brazing material is flowed into the gap, it flows in from the tip of the boss. Therefore, by making the gap at the tip larger, it is possible to make it easier for the brazing material to flow into the gap.

It also makes it easier for the brazing material to flow into the recess. The brazing material that flows into the recess accumulates in the recess. This makes it easier for the brazing material to spread in the circumferential direction in the recess. The brazing material that accumulates in the recess then flows (permeates) toward the base end side of the recess. In this way, the brazing material that permeates the gap can be made uniform in the circumferential direction, so the boss and the piping can be properly brazed. This improves the joint strength between the boss and the piping.

The center of the recess in a predetermined direction and the other end of the boss may be positioned at the same position in the predetermined direction. This configuration allows the brazing material to penetrate more efficiently.

In the heat exchanger according to the first aspect of the present disclosure, the pipe has a refrigerant pipe (30) through which a refrigerant flows, the boss portion is attached to a heat exchange portion (2a) in which the refrigerant exchanges heat, and the brazing structure described in any one of the first to third aspects is applied to the connection portion between the refrigerant pipe and the boss portion.

The brazing method according to the first aspect of the present disclosure is a method for brazing a cylindrical boss portion (20) and a pipe (30) to be inserted into the boss portion, and includes a recess forming process for forming a recess (31) recessed from the outer surface of the pipe, and a brazing process for brazing an area of the outer surface of the pipe that includes the recess to the inner surface of the boss portion.

In addition, in the brazing method according to the second aspect of the present disclosure, in the first aspect, the recess forming step forms the recess by performing a drawing process on the pipe.

In the above configuration, the thickness of the pipe does not change in the recess, so the decrease in the pressure resistance of the pipe can be suppressed.

In addition, in the brazing method according to the third aspect of the present disclosure, in the first aspect, the recess forming step forms the recess by performing a cutting process on the outer surface of the pipe.

In the above configuration, the recess is formed by machining the outer surface of the pipe. Since the inner diameter of the pipe does not change even in the recess, the pressure loss of the fluid flowing inside the pipe can be reduced.

1: Heat exchanger 2a: First plate 2b: Second plate 3a: First inlet side boss portion 3b: Second inlet side boss portion 3c: Second outlet side boss portion 4: Cover plate 5a: Inner fin 5b: Inner fin 6: First fluid 7: Second fluid 8: First flow path 9: Second flow path 10: Brazed structure 20: Boss portion 21: Insertion portion 22: Fixing portion 23: Step portion 30: Refrigerant pipe 31: Recess 40: Brazing material 51: Recess

In order to solve the above problems, the brazing structure, heat exchanger, and brazing method disclosed herein employ the following measures.
A brazing structure according to one aspect of the present disclosure comprises a cylindrical boss portion, and a pipe extending in a predetermined direction, inserted into the boss portion, and having a recess formed therein that is recessed from its outer surface, wherein the boss portion and the pipe are brazed to each other at an area of the outer surface of the pipe that includes the recess and an inner surface of the boss portion, and the recess is formed over the entire circumferential area of the pipe .

A brazing method according to one aspect of the present disclosure is a method for brazing a cylindrical boss portion to a pipe inserted into the boss portion, the method including a recess forming process for forming a recess that is recessed from an outer surface of the pipe, and a brazing process for brazing an area of the outer surface of the pipe that includes the recess to an inner surface of the boss portion , wherein the recess is formed over the entire circumferential area of the pipe in the recess forming process .

The refrigerant pipe 30 is inserted into the boss portion 20. The refrigerant pipe 30 extends in a predetermined direction. Refrigerant discharged from a compressor and an expansion valve provided in the refrigerant circuit flows through the inside of the refrigerant pipe 30. The refrigerant pipe 30 supplies the refrigerant to flow paths (first flow path 8 and second flow path 9) provided in the heat exchanger 1 via the boss portion 20, and also discharges the refrigerant from the flow paths.

Claims (7)

A cylindrical boss portion;
a pipe extending in a predetermined direction, inserted into the boss portion, and having a recess formed therein that is recessed from an outer surface thereof;
The boss portion and the pipe have a brazed structure in which a region of the outer surface of the pipe, which includes the recess, and an inner surface of the boss portion are brazed to each other. The brazed structure according to claim 1, wherein the recess is formed over the entire circumferential area of the pipe. The boss portion has a base end attached to a workpiece,
The brazing structure according to claim 1 , wherein the boss portion and the pipe are arranged such that the recess and a tip of the boss portion are at the same position in a predetermined direction. The pipe includes a refrigerant pipe through which a refrigerant flows,
The boss portion is attached to a heat exchange portion where the refrigerant exchanges heat,
A heat exchanger, comprising: a connecting portion between the refrigerant pipe and the boss portion, the connecting portion being configured to connect the refrigerant pipe and the boss portion, the brazing structure according to any one of claims 1 to 3. A method for brazing a cylindrical boss portion and a pipe to be inserted into the boss portion, comprising the steps of:
a recess forming step of forming a recess in the pipe from an outer surface thereof;
a brazing step of brazing a region of the outer surface of the pipe, the region including the recess, to an inner surface of the boss portion. The brazing method according to claim 5, wherein the recess forming step forms the recess by performing a drawing process on the pipe. The brazing method according to claim 5 , wherein the recess forming step forms the recess by performing a cutting process on an outer surface of the pipe.