Method for manufacturing a bonded body and the bonded body

Abstract

To provide a technique which prevents a substance contained in a bonding material to be used for a joint portion from eluding into a flow channel, in forming a component including the flow channel.SOLUTION: Provided is a method for manufacturing a joint body which is formed by bonding two pieces of metal plates, and comprises a flow channel part where a liquid passes through. The method for manufacturing a joint body includes an arrangement process and a bonding process. In the arrangement process, two pieces of metal plates and a bonding material are arranged so that the bonding material is provided between the two pieces of metal plates. In the bonding process, one of the two pieces of metal plates is irradiated with a laser beam at a predetermined position on a flow channel part side beyond a position where the bonding material is arranged, whereby a first junction and a second junction are formed. The first junction is formed according to laser welding. The second junction is formed when the bonding material melts according to heat generated during the laser welding.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a joined body and a joined body.

Background Art

[0002] Patent Document 1 discloses that brazing is used for joining joining surfaces of a plurality of brazing sheets used in a heat exchanger. The space between non-joining adjacent surfaces adjacent to the joining surfaces of the plurality of brazing sheets in a state where the joining surfaces are joined by brazing functions as a cooling flow path through which cooling water flows.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the brazed joint portion in the brazing sheet as described above comes into contact with the cooling water, there is a problem that the flux contained in the brazing material may elute into the cooling water.

[0005] One aspect of the present disclosure aims to provide a technique for suppressing the elution of substances contained in a joining material used for a joining portion into a flow path when forming a component having a flow path.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a method for manufacturing a joined body including a flow path portion through which a liquid passes, the flow path portion being 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 the 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, laser light is irradiated onto one of the two metal plates at a predetermined position on the flow path portion side with respect to 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 laser light is irradiated to perform welding. The second joining portion is formed by melting the joining material due to heat generated during the laser welding.

[0007] In such a configuration, laser light is irradiated at a predetermined position on the flow path portion side with respect to the position where the joining material is arranged. For this reason, the first joining portion formed by laser welding is located closer to the flow path portion side than the second joining portion formed by melting the joining material. That is, the first joining portion is located between the flow path portion and the second joining portion. Thereby, it is difficult for the liquid passing through the flow path portion to come into contact with the second joining portion. Therefore, it is possible to suppress the elution of substances contained in the joining material forming the second joining portion into the flow path. Further, by forming the first joining portion and the second joining portion, the sealing property and the joining strength can be improved as compared with a configuration in which only one of the first joining portion and the second joining portion is formed.

[0008] In one aspect of the present disclosure, the bonding material may be a brazing material. In such a configuration, the brazing material melted by the heat generated during laser welding solidifies to form the second joint portion. Then, since the liquid passing through the flow path portion and the second joint portion are less likely to come into contact due to the first joint portion located between the second joint portion and the flow path portion, it is possible to suppress the flux contained in the brazing material from eluting into the flow path. Further, the sealing performance of the first joint portion formed by laser welding can be assisted by brazing with the brazing material. Further, since the second joint portion is formed by the solidification of the brazing material melted by the heat generated during the laser welding for forming the first joint portion, a heating furnace such as that used in brazing is not required when forming the second joint portion.

[0009] In one aspect of the present disclosure, the laser light may be incident obliquely on the two metal plates at a predetermined position. In such a configuration, at the predetermined position, the laser light is incident obliquely on the metal plate. Therefore, compared with the case where the laser light is incident substantially perpendicular to the metal plate at the predetermined position, the penetration distance of the melted metal melted by the laser welding at the first joint portion becomes longer, and as a result, the bonding strength can be improved.

[0010] In one aspect of the present disclosure, the first joint portion and the second joint portion may be formed so as to extend along the flow path portion. In such a configuration, since the first joint portion and the second joint portion extend along the flow path portion, the first joint portion is always located between the liquid passing through the flow path portion and the second joint portion. Thereby, since the second joint portion and the flow path portion are physically separated by the first joint portion, the possibility of contact between the liquid and the second joint portion is low. Therefore, it is possible to further suppress the substance contained in the bonding material forming the second joint portion from eluting into the flow path.

[0011] One aspect of the present disclosure is a joined body formed by joining two metal plates, comprising a first joined portion, a second joined portion, and a flow path portion through which a liquid passes. The first joined portion is formed by laser welding in which two metal plates are joined by irradiating laser light for welding. The second joined portion is formed by joining two metal plates with a joining material provided between the 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 first joined portion is located between the flow path portion and the second joined portion. In such a configuration, the first joined portion is located between the flow path portion and the second joined portion. Thereby, it is difficult for the liquid passing through the flow path portion to come into contact with the second joined portion. Therefore, it is possible to suppress the elution of substances contained in the joining material forming the second joined portion into the flow path. Further, by forming the first joined portion and the second joined portion, the sealing property and the joining strength can be improved as compared with a configuration in which only one of the first joined portion and the second joined portion is formed.

Brief Description of Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0013] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Configuration] The joined body 100 shown in FIGS. 1 and 2C is a member formed by joining two metal plates 1a and 1b in a stacked state. The joined body 100 is formed such that a flow path portion 2 is provided by a space surrounded by the two metal plates 1a and 1b. Hereinafter, among the two metal plates 1a and 1b, the metal plate disposed on the upper side is referred to as the upper metal plate 1a, and the metal plate disposed 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 is illustrated, the arrangement of the two metal plates 1a and 1b is not limited to the illustrated direction. In FIG. 1, the illustration of the upper metal plate 1a is omitted for convenience of explanation. The joined body 100 is used, for example, in a heat exchanger that allows cooling water to flow through the flow path portion 2. The joined body 100 includes an upper metal plate 1a, a lower metal plate 1b, a flow path portion 2, a first joining portion 3, and a second joining portion 4.

[0014] 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 a contact portion 13. The flat portion 11 is a portion that extends in a planar shape parallel to and spaced apart from the lower metal plate 1b that extends in a planar shape. The inclined portion 12 is a portion that extends from the end of the flat portion 11 toward the metal plate 1b. The contact portion 13 is a portion that extends in a planar shape parallel to the lower metal plate 1b from the end of the inclined portion 12, and is a portion that contacts 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 extend in a planar shape, and the lower metal plate may have the flat portion, the inclined portion, and the contact portion described above. Also, both the upper metal plate and the lower metal plate may have the flat portion, the inclined portion, and the contact portion described above. Note that the shapes of the upper metal plate and the lower metal plate are not limited to the shapes described above, and they 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 circular shape and a polygonal shape.

[0015] The flow path portion 2 is the non-joint portion of the upper metal plate 1a and the lower metal plate 1b in the joined body 100 in the joined state, and is constituted by the space surrounded by the upper metal plate 1a and the lower metal plate 1b. In the present embodiment, it is the space formed between the flat portion 11 and the inclined portion 12 of the upper metal plate 1a and the lower metal plate 1b. In the flow path portion 2, for example, a liquid such as cooling water used for recovering heat in a heat exchanger passes through.

[0016] The first joint portion 3 and the second joint portion 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 portion 3 is formed using a laser oscillator 200 configured to irradiate a laser beam L. The first joint portion 3 is formed by laser welding in which welding is performed by irradiating the laser beam L. The first joint portion 3 is formed by irradiating the laser beam L onto 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. The outer surface is the surface of the upper metal plate 1a and the lower metal plate 1b that does not face the bonding material 41 shown in FIG. 2A disposed between the upper metal plate 1a and the lower metal plate 1b. Specifically, the first joint portion 3 is formed by melting the upper metal plate 1a and the lower metal plate 1b using the laser beam L irradiated from the laser oscillator 200 as a heat source and joining the upper metal plate 1a and the lower metal plate 1b together.

[0017] The second joint portion 4 is formed by applying heat to the bonding material 41 disposed between the upper metal plate 1a and the lower metal plate 1b and allowing the bonding material 41 to solidify after melting. In this embodiment, the bonding material 41 is melted by the heat generated by the irradiation of the laser beam L when forming the first joint portion 3. That is, the second joint portion 4 is formed by the solidification of the bonding material 41 melted by the heat generated during laser welding. In this embodiment, as the bonding material 41, a brazing material having a melting point lower than that of the upper metal plate 1a and the lower metal plate 1b, for example, is used. As the brazing material used for the bonding material 41, for example, when the two metal plates 1a and 1b are made of copper, copper brazing, phosphorus copper brazing, etc. are desirable, and when the two metal plates 1a and 1b are made of aluminum, aluminum brazing is desirable.

[0018] In the present embodiment, as shown in FIGS. 1 and 2C, in the joined body 100, the first joining portion 3 is located between the flow path portion 2 through which liquid passes and the second joining portion 4. Further, as shown in FIG. 1, the first joining portion 3 and the second joining portion 4 are formed so as to extend along the flow path portion 2. In other words, the first joining portion 3 and the second joining portion 4 are formed so as to extend along the flow direction of the liquid passing through the flow path portion 2. In the example shown in FIG. 1, the joined body 100 is joined such that a meandering flow path portion 2 having a plurality of bent portions is formed.

[0019] [2. Method for manufacturing joined body] Next, a method for manufacturing the joined body 100 will be described. The method for manufacturing the joined body 100 includes an arranging step and a joining step.

[0020] <Arranging step> First, as shown in FIG. 2A, the upper metal plate 1a, the lower metal plate 1b, and the joining material 41 are arranged such that the joining material 41 is provided between the upper metal plate 1a and the lower metal plate 1b. Specifically, the joining material 41 is arranged between the contact portion 13 of the upper metal plate 1a and the lower metal plate 1b. The joining material 41 may be arranged so as to be inserted between the upper metal plate 1a and the lower metal plate 1b which are arranged to face each other. Further, the joining 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 joining material 41.

[0021] <Joining step> Next, as shown in FIG. 2B, laser light L is irradiated onto the outer surface of the upper metal plate 1a at a predetermined position on the side of the flow path portion 2 rather than the position where the bonding material 41 between the upper metal plate 1a and the lower metal plate 1b is disposed, using a laser oscillator 200. Thereby, a first joint portion 3 is formed between the position where the bonding material 41 is disposed and the flow path portion 2. In the present embodiment, the laser light L is incident substantially perpendicularly to the outer surface of the upper metal plate 1a, and the first joint portion 3 is formed. Note that the predetermined position on the side of the flow path portion 2 is a range in which the heat H by the laser light L reaches the bonding material 41 disposed between the upper metal plate 1a and the lower metal plate 1b, and is a position within the range where the bonding material 41 melts due to the heat H generated during laser welding.

[0022] Then, due to the heat H during laser welding of the upper metal plate 1a and the lower metal plate 1b generated by the irradiation of the laser light L, the bonding material 41 melts and spreads. As the thus melted and spread bonding material 41 cools and solidifies, a second joint portion 4 as shown in FIG. 2C is formed. By the method described above, a joined body 100 is formed such that the first joint portion 3 is positioned between the flow path portion 2 and the second joint portion 4.

[0023] [3. Effects] According to the embodiment described in detail above, the following effects can be obtained.

[0024] (3a) In this embodiment, the laser beam L is irradiated at a predetermined position on the side of the flow path portion 2 rather than the position where the bonding material 41 is disposed. For this reason, the first joint portion 3 formed by laser welding is located on the side of the flow path portion 2 rather than the second joint portion 4 formed by melting the bonding material 41. That is, the first joint portion 3 is located between the flow path portion 2 and the second joint portion 4. Further, in the above embodiment, since the first joint portion 3 and the second joint portion 4 extend along the flow path portion 2, the first joint portion 3 is always located between the liquid passing through the flow path portion 2 and the second joint portion 4. Thereby, since the second joint portion 4 and the flow path portion 2 are physically separated by the first joint portion 3, the possibility that the liquid passing through the flow path portion 2 and the second joint portion 4 come into contact is low. Therefore, it is possible to suppress the substance contained in the bonding material 41 forming the second joint portion 4 from eluting into the flow path.

[0025] (3b) In this embodiment, since the first joint portion 3 and the second joint portion 4 are formed, the sealing property and the joint strength in the joint of the upper metal plate 1a and the lower metal plate 1b can be improved as compared with a configuration in which only one of the first joint portion 3 and the second joint portion 4 is formed.

[0026] (3c) In this embodiment, a brazing material is used as the bonding material 41, and the second joint portion 4 is formed by the solidification of the brazing material melted by the heat H generated during laser welding. And since it is difficult for the liquid passing through the flow path portion 2 and the second joint portion 4 to come into contact due to the first joint portion 3 located between the second joint portion 4 and the flow path portion 2, it is possible to suppress the flux contained in the brazing material from eluting into the flow path. For example, when the flux contained in the brazing material elutes into the cooling water used in the heat exchanger, the insulation of the cooling water decreases. When the cooling water with the eluted flux leaks out of the heat exchanger and comes into contact with a conductive portion such as an electrode in the apparatus provided with the heat exchanger, a short circuit may occur. Therefore, as a result of suppressing the flux contained in the brazing material from eluting into the flow path, even when the cooling water leaks out of the flow path, it is possible to suppress the occurrence of a short circuit or the like.

[0027] In addition, in this embodiment, the sealing performance of the first joint portion 3 formed by laser welding can be assisted by brazing with a brazing material. Further, the second joint portion 4 is formed by the hardening of the brazing material melted by the heat H generated during the laser welding for forming the first joint portion 3. Therefore, when forming the second joint portion 4, a heating furnace such as that used for brazing is not required. Also, since the brazing material can be melted without using a heating furnace, the time for forming the second joint portion 4, that is, the joining time of the upper metal plate 1a and the lower metal plate 1b can be shortened as compared with the case of using a heating furnace.

[0028] [4. Other Embodiments] As described above, the embodiments of the present disclosure have been described. Needless to say, the present disclosure is not limited to the above embodiments and can take various forms.

[0029] (4a) In the above embodiment, the laser beam L is incident substantially perpendicularly to the outer surface of the upper metal plate 1a to form the first joint portion 3. However, the incident angle of the laser beam L for forming the first joint portion is not limited to this. For example, as shown in FIG. 3, the laser beam L may be obliquely incident on the outer surface of the upper metal plate 1a to form the first joint portion 3a. Here, being obliquely incident on the outer surface of the upper metal plate 1a means being incident at a predetermined angle θ with respect to the virtual line S orthogonal to the outer surface. Specifically, with respect to the virtual line S, the predetermined angle θ can take a value of about 70° or less. It is preferably about 20° or more and preferably about 50° or less. Thus, when the laser beam L is obliquely incident, the penetration distance in the upper metal plate 1a and the lower metal plate 1b, that is, the length of the first joint portion 3a can be made longer as compared with the case where the laser beam L is incident substantially perpendicularly. Therefore, the joining strength of the upper metal plate 1a and the lower metal plate 1b can be improved.

[0030] Also, when the laser beam L is obliquely incident on the outer surface of the upper metal plate 1a, the direction in which the laser beam L is tilted is not limited. For example, the direction in which the laser beam L is tilted can take various directions of 360° around the virtual line S. For example, the laser beam L may be tilted so that the laser beam L is obliquely incident on the outer surface of the upper metal plate 1a from the side where the bonding material 41 is disposed toward the flow path portion 2 side. Also, for example, the laser beam L may be tilted so that the laser beam L is obliquely incident on the outer surface of the upper metal plate 1a from the flow path portion 2 side toward the side where the bonding material 41 is disposed. Also, for example, the laser beam L may be tilted so that the laser beam L is obliquely incident on the outer surface of the upper metal plate 1a along the length direction of the flow path portion 2 from the downstream side to the upstream side or from the upstream side to the downstream side.

[0031] Also, for example, the two first bonding portions 3a disposed on both sides of the flow path portion 2 to form the flow path portion 2 may be formed so as to be tilted in the same direction by tilting the laser beam L as described above. Specifically, as shown in FIGS. 4A and 4B, with respect to the outer surface of the upper metal plate 1a, one laser beam L is tilted and irradiated from the side where the bonding material 41 is disposed toward the flow path portion 2 side, and the other laser beam L is tilted and irradiated from the flow path portion 2 side toward the side where the bonding material 41 is disposed, so that the two first bonding portions 3a disposed on both sides of the flow path portion 2 are formed so as to be tilted in the same direction.

[0032] Further, for example, the two first joining portions 3a arranged on both sides of the flow path portion 2 to form the flow path portion 2 may be formed so as to incline the laser beam L as described above and incline in different directions. Specifically, as shown in FIG. 4C, with respect to the outer surface of the upper metal plate 1a, the laser beams L on both sides are inclined and irradiated from the side where the joining material 41 is arranged toward the flow path portion 2 side, so that the two first joining portions 3a arranged on both sides of the flow path portion 2 are formed to incline in different directions. Also, as shown in FIG. 4D, with respect to the outer surface of the upper metal plate 1a, the laser beams L on both sides are inclined and irradiated from the flow path portion 2 side toward the side where the joining material 41 is arranged, so that the two first joining portions 3a arranged on both sides of the flow path portion 2 are formed to incline in different directions.

[0033] Among the above-described modes, the mode shown in FIG. 4C in which the two first joining portions 3a arranged on both sides of the flow path portion 2 are formed by inclining and irradiating the laser beams L on both sides from the side where the joining material 41 is arranged toward the flow path portion 2 side with respect to the outer surface of the upper metal plate 1a is the most preferable. In the mode shown in FIG. 4C, since the portion where the temperature increases due to the irradiation of the laser beam L is closer to the joining material 41, the heat is most easily transmitted to the joining material 41. For this reason, the joining material 41 can be easily melted by the heat during laser welding.

[0034] (4b) The method of forming the first joining portion 3 and the second joining portion 4 described in the above-described method for manufacturing the joined body 100 is not limited to the formation of the joined body 100 used in the heat exchanger, and can be utilized, for example, also in the joining of pipes used other than the heat exchanger.

[0035] (4c) In the above embodiment, copper and aluminum are exemplified as the metals having high thermal conductivity used for the upper metal plate 1a and the lower metal plate 1b, but other metals capable of laser welding by irradiation of the laser beam L may be used for the upper metal plate 1a and the lower metal plate 1b. Examples of other metals include stainless steel, iron, and the like.

[0036] (4d) In the above embodiment, an example was given in which a brazing material is used as the bonding material 41, but the bonding material is not limited to this. As the bonding material, for example, an adhesive of a thermoreversible resin or the like may be used.

[0037] (4e) The functions of one component in the above embodiment may be dispersed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Also, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added to, replaced with, etc. the configuration of another above embodiment. Note that all aspects included in the technical idea specified from the language described in the claims are embodiments of the present disclosure.

Explanation of Reference Numerals

[0038] 1a... upper metal plate, 1b... lower metal plate, 2... flow path portion, 3, 3a... first joint portion, 4... second joint portion, 11... flat portion, 12... inclined portion, 13... contact portion, 41... bonding material, 100... bonded body, 200... laser oscillator, H... heat, L... laser light, S... virtual line.

Claims

1. A method for manufacturing a joined body including a flow path portion through which a liquid passes, the joined body being formed by joining two metal plates, wherein 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, an arranging step of arranging the two metal plates and the joining material so that the joining material is provided between the two metal plates; a joining step of forming a first joining portion formed by laser welding in which laser light is irradiated onto one of the two metal plates at a predetermined position on the flow path portion side with respect to the position where the joining material is arranged and welding is performed by irradiating the laser light, and a second joining portion formed by melting the joining material by heat generated during the laser welding; The method for manufacturing a joined body, comprising:

2. The method for manufacturing a joined body according to claim 1, wherein the joining material is a brazing material.

3. The method for manufacturing a joined body according to claim 1 or claim 2, wherein the laser light is incident obliquely on the two metal plates at the predetermined position.

4. The method for manufacturing a joined body according to any one of claims 1 to 3, wherein the first joining portion and the second joining portion are formed so as to extend along the flow path portion.

5. A joined body formed by joining two metal plates, a first joining portion in which the two metal plates are joined by laser welding in which laser light is irradiated and welding is performed; a second joining portion in which the two metal plates are joined by a joining material provided between the two metal plates; a flow path portion through which a liquid passes, the flow path portion being a non-joined portion of the two metal plates and being constituted by a space surrounded by the two metal plates; comprising: wherein the first joining portion is located between the flow path portion and the second joining portion.

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