JP7684236B2 - Method for manufacturing joined body and joined body - Google Patents

Description

This disclosure relates to a method for manufacturing a bonded body and to a bonded body.

Patent Document 1 discloses that brazing is used to join the joining surfaces of multiple brazing sheets used in a heat exchanger. The space between the non-jointed adjacent surfaces adjacent to the joining surfaces of multiple brazing sheets in a state in which the joining surfaces are joined by brazing functions as a cooling flow path through which cooling water flows.

JP 2021-63263 A

However, there was a problem that when the brazed joint in the brazing sheet described above came into contact with cooling water, the flux contained in the brazing material could dissolve into the cooling water.

One aspect of the present disclosure aims to provide a technology that prevents substances contained in a bonding material used in a bonding portion from leaching into the flow path when forming a part having a flow path.

One aspect of the present disclosure is a method for manufacturing a joined body having a flow path portion through which a liquid passes, formed by joining two metal plates. The flow path portion is a non-joined portion of the two metal plates, and is constituted by a space surrounded by the two metal plates. The method for manufacturing a joined body includes an arrangement step and a joining step. In the arrangement step, the two metal plates and the joining material are arranged so that the joining material is provided between the two metal plates. In the joining step, a laser beam is irradiated onto one of the two metal plates at a predetermined position on the flow path portion side from the position where the joining material is arranged, to form a first joining portion and a second joining portion. The first joining portion is formed by laser welding, in which welding is performed by irradiating a laser beam. The second joining portion is formed by melting the joining material due to heat generated during laser welding.

In such a configuration, the laser light is irradiated at a predetermined position on the flow path side of the position where the bonding material is arranged. Therefore, the first bonding portion formed by laser welding is located on the flow path side of the second bonding portion formed by melting the bonding material. In other words, the first bonding portion is located between the flow path portion and the second bonding portion. This makes it difficult for the liquid passing through the flow path portion to come into contact with the second bonding portion. Therefore, it is possible to suppress the elution of the substance contained in the bonding material forming the second bonding portion into the flow path. In addition, by forming the first bonding portion and the second bonding portion, it is possible to improve the sealing property and bonding strength compared to a configuration in which only one of the first bonding portion and the second bonding portion is formed.

In one aspect of the present disclosure, the joining material may be a brazing material. In such a configuration, the second joining portion is formed by solidifying the molten brazing material due to the heat generated during laser welding. The first joining portion located between the second joining portion and the flow path portion makes it difficult for the liquid passing through the flow path portion to come into contact with the second joining portion, so that it is possible to suppress the flux contained in the brazing material from dissolving into the flow path. In addition, the sealing property of the first joining portion formed by laser welding can be assisted by brazing with the brazing material. In addition, since the second joining portion is formed by solidifying the molten brazing material due to the heat generated during laser welding to form the first joining portion, a heating furnace such as that used for brazing is not required when forming the second joining portion.

In one aspect of the present disclosure, the laser light may be incident on the two metal plates at an angle at a predetermined position. In such a configuration, the laser light is incident on the metal plates at an angle at a predetermined position. Therefore, compared to when the laser light is incident on the metal plates approximately perpendicularly at the predetermined position, the penetration distance of the metal melted by the laser welding at the first joint is longer, and as a result, the joint strength can be improved.

In one aspect of the present disclosure, the first and second joints may be formed to extend along the flow path. In such a configuration, the first and second joints extend along the flow path, so that the first joint is always located between the liquid passing through the flow path and the second joint. This physically isolates the second joint from the flow path by the first joint, making it less likely that the liquid will come into contact with the second joint. This makes it possible to further suppress the elution of substances contained in the bonding material that forms the second joint into the flow path.

One aspect of the present disclosure is a joint formed by joining two metal plates, and includes a first joint, a second joint, and a flow path through which a liquid passes. The first joint is formed by joining two metal plates by laser welding, which involves irradiating a laser beam to perform welding. The second joint is formed by joining two metal plates with a joining material provided between the two metal plates. The flow path is a non-joined portion of the two metal plates, and is formed by a space surrounded by the two metal plates. The first joint is located between the flow path and the second joint. In this configuration, the first joint is located between the flow path and the second joint. This makes it difficult for the liquid passing through the flow path to come into contact with the second joint. Therefore, it is possible to suppress the elution of a substance contained in the joining material forming the second joint into the flow path. In addition, by forming the first joint and the second joint, it is possible to improve the sealing property and the joining strength compared to a configuration in which only one of the first joint and the second joint is formed.

1 is a schematic cross-sectional view of a bonded body having a flow path through which a liquid passes, as viewed from above. FIG. Fig. 2A is a schematic cross-sectional view showing a state where a bonding material is disposed between two metal plates in a disposing step, Fig. 2B is a schematic cross-sectional view showing a state where a first bonding portion is formed by laser welding in a joining step, and Fig. 2C is a schematic cross-sectional view showing a state where a second bonding portion is formed by solidifying the bonding material melted by heat generated during laser welding in the joining step. 10 is a schematic cross-sectional view showing a state in which a first joint portion and a second joint portion are formed by laser light that is obliquely incident on the outer surface of a metal plate at a predetermined position in a joining process. FIG. 4A and 4B are diagrams showing two modes in which one side of the laser light is irradiated at an angle from the side where the bonding material is arranged toward the flow path section side, and the other side of the laser light is irradiated at an angle from the flow path section side toward the side where the bonding material is arranged. Fig. 4C is a diagram showing a mode in which both sides of the laser light are irradiated at an angle from the side where the bonding material is arranged toward the flow path section side. Fig. 4D is a diagram showing a mode in which both sides of the laser light are irradiated at an angle from the flow path section side toward the side where the bonding material is arranged.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.
[1. Configuration]
The joined body 100 shown in FIG. 1 and FIG. 2C is a member formed by joining two metal plates 1a and 1b in a superimposed state. The joined body 100 is formed so as to have a flow path 2 formed by a space surrounded by the two metal plates 1a and 1b. Hereinafter, the metal plate arranged on the upper side of the two metal plates 1a and 1b is referred to as the upper metal plate 1a, and the metal plate arranged below the upper metal plate 1a is referred to as the lower metal plate 1b. Although the configuration in which the two metal plates 1a and 1b forming the joined body 100 are arranged in the vertical direction has been illustrated, the arrangement of the two metal plates 1a and 1b is not limited to the exemplary direction. In FIG. 1, the upper metal plate 1a is omitted for convenience of explanation. The joined body 100 is used, for example, in a heat exchanger in which cooling water flows through the flow path 2. The joined body 100 comprises an upper metal plate 1 a , a lower metal plate 1 b , a flow path portion 2 , a first joining portion 3 , and a second joining portion 4 .

The upper metal plate 1a and the lower metal plate 1b are formed of a metal with high thermal conductivity. For the upper metal plate 1a and the lower metal plate 1b, it is desirable to use, for example, copper, aluminum, etc. In the example shown in FIG. 2A, the upper metal plate 1a has a flat portion 11, an inclined portion 12, and an abutment portion 13. The flat portion 11 is a portion that spreads flatly in parallel with the flat lower metal plate 1b at a distance. The inclined portion 12 is a portion that extends from the end of the flat portion 11 toward the metal plate 1b. The abutment portion 13 is a portion that spreads flatly in parallel with the lower metal plate 1b from the end of the inclined portion 12, and is a portion that abuts against the lower metal plate 1b via the first joint portion 3 and the second joint portion 4 described later. Note that the upper metal plate may spread flatly, and the lower metal plate may have the flat portion, inclined portion, and abutment portion described above. In addition, both the upper metal plate and the lower metal plate may have the flat portion, inclined portion, and abutment portion described above. The shapes of the upper metal plate and the lower metal plate are not limited to the above shapes, and may have various shapes. That is, the shape of the flow path portion formed by the two metal plates 1a and 1b may have various shapes, such as a circle, a polygon, etc.

The flow path section 2 is a non-jointed portion of the upper metal plate 1a and the lower metal plate 1b in the joined body 100, and is composed of a space surrounded by the upper metal plate 1a and the lower metal plate 1b. In this embodiment, it is a space formed between the flat portion 11 and the inclined portion 12 of the upper metal plate 1a and the lower metal plate 1b. A liquid such as cooling water used to recover heat in a heat exchanger passes through the flow path section 2.

The first joint 3 and the second joint 4 are formed between the upper metal plate 1a and the lower metal plate 1b, and are the portions where the upper metal plate 1a and the lower metal plate 1b are joined together. As shown in FIG. 2B, the first joint 3 is formed using a laser oscillator 200 configured to irradiate laser light L. The first joint 3 is formed by laser welding, which irradiates laser light L to perform welding. The first joint 3 is formed by irradiating the outer surface of either the upper metal plate 1a or the lower metal plate 1b, in this embodiment, the outer surface of the upper metal plate 1a, with laser light L. The outer surface is the surface of the upper metal plate 1a and the lower metal plate 1b that does not face the joining material 41 shown in FIG. 2A and arranged between the upper metal plate 1a and the lower metal plate 1b. Specifically, the first joint 3 is formed by melting the upper metal plate 1a and the lower metal plate 1b using the laser light L irradiated from the laser oscillator 200 as a heat source, thereby joining the upper metal plate 1a and the lower metal plate 1b.

The second joint 4 is formed by applying heat to the joint material 41 disposed between the upper metal plate 1a and the lower metal plate 1b, and by melting and then solidifying the joint material 41. In this embodiment, the joint material 41 melts due to heat generated by irradiation with the laser light L when forming the first joint 3. That is, the second joint 4 is formed by solidifying the joint material 41 that has been melted by heat generated during laser welding. In this embodiment, the joint material 41 is made of, for example, a brazing material having a lower melting point than the upper metal plate 1a and the lower metal plate 1b. For example, when the two metal plates 1a and 1b are made of copper, the brazing material used as the joint material 41 is preferably copper brazing or phosphorus copper brazing, and when the two metal plates 1a and 1b are made of aluminum, aluminum brazing is preferably used.

In this embodiment, as shown in Figs. 1 and 2C, in the joined body 100, the first joint 3 is located between the flow path section 2 through which the liquid passes and the second joint section 4. Also, as shown in Fig. 1, the first joint section 3 and the second joint section 4 are formed to extend along the flow path section 2. In other words, the first joint section 3 and the second joint section 4 are formed to extend along the flow direction of the liquid passing through the flow path section 2. In the example shown in Fig. 1, the joined body 100 is joined so that a meandering flow path section 2 having multiple bent portions is formed.

[2. Manufacturing method of bonded body]
Next, a description will be given of a method for manufacturing the bonded body 100. The method for manufacturing the bonded body 100 includes a placement step and a bonding step.

<Placement process>
First, as shown in Fig. 2A, the upper metal plate 1a, the lower metal plate 1b, and the bonding material 41 are arranged so that the bonding material 41 is provided between the upper metal plate 1a and the lower metal plate 1b. Specifically, the bonding material 41 is arranged between the abutting portion 13 of the upper metal plate 1a and the lower metal plate 1b. The bonding material 41 may be arranged so as to be inserted between the upper metal plate 1a and the lower metal plate 1b arranged to face each other. Alternatively, the bonding material 41 may be arranged on the lower metal plate 1b, and then the upper metal plate 1a may be arranged above the lower metal plate 1b so as to sandwich the bonding material 41.

<Joining process>
Next, as shown in Fig. 2B, at a predetermined position on the flow path 2 side of the position where the bonding material 41 between the upper metal plate 1a and the lower metal plate 1b is arranged, a laser beam L is irradiated to the outer surface of the upper metal plate 1a using a laser oscillator 200. As a result, a first bonding portion 3 is formed between the position where the bonding material 41 is arranged and the flow path 2. In this embodiment, the laser beam L is incident on the outer surface of the upper metal plate 1a approximately perpendicularly to form the first bonding portion 3. The predetermined position on the flow path 2 side is a range where the heat H from the laser beam L reaches the bonding material 41 arranged between the upper metal plate 1a and the lower metal plate 1b, and is a position within a range where the bonding material 41 is melted by the heat H generated during laser welding.

Then, the joining material 41 melts and spreads due to heat H generated during laser welding of the upper metal plate 1a and the lower metal plate 1b by irradiation with the laser light L. The joining material 41 thus melted and spreads cools and solidifies, forming a second joining portion 4 as shown in FIG.
By the above-mentioned method, a bonded body 100 is formed in which the first bonding portion 3 is located between the flow path portion 2 and the second bonding portion 4 .

3. Effects
According to the embodiment described above in detail, the following effects can be obtained.

(3a) In this embodiment, the laser light L is irradiated at a predetermined position on the flow path section 2 side from the position where the bonding material 41 is arranged. Therefore, the first bonding portion 3 formed by laser welding is located closer to the flow path section 2 side than the second bonding portion 4 formed by melting the bonding material 41. That is, the first bonding portion 3 is located between the flow path section 2 and the second bonding portion 4. In addition, in the above embodiment, since the first bonding portion 3 and the second bonding portion 4 extend along the flow path section 2, the first bonding portion 3 is always located between the liquid passing through the flow path section 2 and the second bonding portion 4. As a result, the second bonding portion 4 and the flow path section 2 are physically isolated by the first bonding portion 3, so that the liquid passing through the flow path section 2 is less likely to come into contact with the second bonding portion 4. Therefore, it is possible to suppress the elution of the substance contained in the bonding material 41 forming the second bonding portion 4 into the flow path.

(3b) In this embodiment, the first joint portion 3 and the second joint portion 4 are formed, and therefore the sealing property and joint strength in the joining of the upper metal plate 1a and the lower metal plate 1b can be improved compared to a configuration in which only one of the first joint portion 3 and the second joint portion 4 is formed.

(3c) In this embodiment, a brazing material is used as the joining material 41, and the second joining portion 4 is formed by solidifying the melted brazing material due to heat H generated during laser welding. The first joining portion 3 located between the second joining portion 4 and the flow path portion 2 makes it difficult for the liquid passing through the flow path portion 2 to come into contact with the second joining portion 4, so that it is possible to suppress the flux contained in the brazing material from dissolving into the flow path. For example, if the flux contained in the brazing material dissolves into the cooling water used in the heat exchanger, the insulation of the cooling water decreases. If the cooling water with the flux dissolved in it leaks out of the heat exchanger and comes into contact with a conductive part such as an electrode in a device equipped with the heat exchanger, a short circuit may occur. Therefore, as a result of suppressing the flux contained in the brazing material from dissolving into the flow path, it is possible to suppress the occurrence of a short circuit, etc., even if the cooling water leaks out of the flow path.

In addition, in this embodiment, the sealing properties of the first joint 3 formed by laser welding can be assisted by brazing with a brazing material. Furthermore, the second joint 4 is formed by solidifying the molten brazing material due to heat H generated during laser welding to form the first joint 3. Therefore, a heating furnace as used in brazing is not required when forming the second joint 4. Furthermore, since the brazing material can be melted without using a heating furnace, the time to form the second joint 4, i.e., the time to join the upper metal plate 1a and the lower metal plate 1b, can be shortened compared to when a heating furnace is used.

4. Other embodiments
Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms.

(4a) In the above embodiment, the laser light L is incident on the outer surface of the upper metal plate 1a approximately perpendicularly to form the first joint 3, but the angle of incidence of the laser light L for forming the first joint is not limited to this. For example, as shown in FIG. 3, the laser light L may be incident on the outer surface of the upper metal plate 1a obliquely to form the first joint 3a. Here, the oblique incidence on the outer surface of the upper metal plate 1a means that the laser light is incident at a predetermined angle θ with respect to a virtual line S perpendicular to the outer surface. Specifically, the predetermined angle θ with respect to the virtual line S can be a value of about 70° or less. It is preferably about 20° or more, and preferably about 50° or less. In this way, when the laser light L is incident obliquely, the penetration distance in the upper metal plate 1a and the lower metal plate 1b, i.e., the length of the first joint 3a, can be made longer than when the laser light L is incident approximately perpendicularly. Therefore, the joining strength of the upper metal plate 1a and the lower metal plate 1b can be improved.

In addition, when the laser light L is obliquely incident on the outer surface of the upper metal plate 1a, the direction in which the laser light L is inclined is not limited, and for example, the direction in which the laser light L is inclined can be various directions of 360° centered on the virtual line S. For example, the laser light L may be inclined so that the laser light L is obliquely incident on the outer surface of the upper metal plate 1a from the side where the bonding material 41 is arranged toward the flow path section 2 side. For example, the laser light L may be inclined so that the laser light L is obliquely incident on the outer surface of the upper metal plate 1a from the flow path section 2 side toward the side where the bonding material 41 is arranged. For example, the laser light L may be inclined so that the laser light L is obliquely incident on the outer surface of the upper metal plate 1a from the downstream side to the upstream side or from the upstream side to the downstream side along the length direction of the flow path section 2.

Also, for example, the two first joints 3a arranged on both sides of the flow path section 2 to form the flow path section 2 may be formed so as to be inclined in the same direction by tilting the laser light L as described above. Specifically, as shown in Figures 4A and 4B, the outer surface of the upper metal plate 1a may be irradiated with one side of the laser light L at an angle from the side where the bonding material 41 is arranged toward the flow path section 2 side, and the other side of the laser light L may be irradiated with an angle from the flow path section 2 side toward the side where the bonding material 41 is arranged, so that the two first joints 3a arranged on both sides of the flow path section 2 may be formed so as to be inclined in the same direction.

For example, the two first joints 3a arranged on both sides of the flow path section 2 to form the flow path section 2 may be formed so as to be inclined in different directions by tilting the laser light L as described above. Specifically, as shown in FIG. 4C, the laser light L on both sides may be irradiated at an angle from the side where the bonding material 41 is arranged toward the flow path section 2 side to the outer surface of the upper metal plate 1a, so that the two first joints 3a arranged on both sides of the flow path section 2 are formed so as to be inclined in different directions. Also, as shown in FIG. 4D, the laser light L on both sides may be irradiated at an angle from the flow path section 2 side toward the side where the bonding material 41 is arranged to the outer surface of the upper metal plate 1a, so that the two first joints 3a arranged on both sides of the flow path section 2 are formed so as to be inclined in different directions.

Of the above-mentioned aspects, the aspect shown in FIG. 4C is the most preferred, in which the laser light L is irradiated at an angle from the side where the joining material 41 is located toward the flow path section 2 side to the outer surface of the upper metal plate 1a, forming two first joining sections 3a arranged on both sides of the flow path section 2. In the aspect shown in FIG. 4C, the part that becomes hotter due to the irradiation of the laser light L is closer to the joining material 41, so heat is most easily transferred to the joining material 41. This makes it easier for the joining material 41 to melt due to the heat generated during laser welding.

(4b) The method for forming the first joint 3 and the second joint 4 described in the manufacturing method of the joint 100 described above is not limited to the formation of the joint 100 used in a heat exchanger, and can also be used, for example, when joining pipes used for purposes other than heat exchangers.

(4c) In the above embodiment, copper and aluminum are exemplified as metals with high thermal conductivity used for the upper metal plate 1a and the lower metal plate 1b, but other metals that can be laser welded by irradiation with laser light L may be used for the upper metal plate 1a and the lower metal plate 1b. Examples of other metals include stainless steel and iron.

(4d) In the above embodiment, a brazing material is used as the bonding material 41, but the bonding material is not limited to this. For example, a thermo-reversible resin adhesive may be used as the bonding material.

(4e) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. In addition, part of the configuration of the above embodiments may be omitted. In addition, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical idea identified from the wording of the claims are embodiments of the present disclosure.

1a...upper metal plate, 1b...lower metal plate, 2...flow path section, 3, 3a...first joint section, 4...second joint section, 11...flat section, 12...inclined section, 13...contact section, 41...joint material, 100...joint body, 200...laser oscillator, H...heat, L...laser light, S...virtual line.

Claims (5)

A method for manufacturing a bonded body having a flow path portion through which a liquid passes, the method being formed by bonding two metal plates, comprising the steps of:
The flow path portion is a non-jointed portion of the two metal plates and is formed by a space surrounded by the two metal plates,
a positioning step of positioning the two metal plates and the bonding material so that a bonding material is provided between the two metal plates;
a joining process for forming a first joint portion formed by laser welding in which a laser beam is irradiated onto one of the two metal plates at a predetermined position on the flow path side of a position where the joining material is disposed, and a second joint portion formed by melting the joining material by heat generated during the laser welding;
A method for manufacturing a bonded body comprising the steps of: A method for producing the bonded body according to claim 1, comprising the steps of:
The method for manufacturing a joined body, wherein the joining material is a brazing material. A method for producing the bonded body according to claim 1 or 2, comprising the steps of:
A method for manufacturing a joined body, wherein the laser light is obliquely incident on the two metal plates at the predetermined position. A method for producing a bonded body according to any one of claims 1 to 3, comprising the steps of:
The first bonded portion and the second bonded portion are formed to extend along the flow path portion. A joint formed by joining two metal plates,
a first joint portion in which the two metal plates are joined by laser welding in which welding is performed by irradiating a laser beam;
a second joint portion in which the two metal plates are joined by a joint material provided between the two metal plates;
a flow path portion through which a liquid passes, the flow path portion being a non-bonded portion of the two metal plates and being formed by a space surrounded by the two metal plates;
Equipped with
The first joint portion is located between the flow path portion and the second joint portion.

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