JP2024012566A - Method for manufacturing metal structure and metal structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a metal structure, which can ensure a design freedom while suppressing and even preventing generation of a defect in a joined part and complication of a manufacturing process.

SOLUTION: In a metal structure manufacturing method, the metal structure includes two metal members stacked together in a perpendicular direction to be joined through friction agitation joining, the two metal members are stacked together in the perpendicular direction to form an assembly having an internal space between the two metal members, the assembly has a discontinuous part formed by the two metal members which are not joined but contact or come close to each other to be discontinuous at positions where they are exposed to the internal space therein, and a boundary formed between the two metal members in a manner that the two metal members are not joined but contact or come close to each other at positions where they are exposed to the internal space therein.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a method for manufacturing a metal structure and a metal structure.

As a conventional metal structure, there is a metal structure that includes a main body and a lid. A lid groove is formed in the main body. A concave groove is further formed on the bottom surface of the lid groove of the main body. A lid portion is fitted into the lid groove. The main body portion and the lid portion around the lid groove are joined. As a result, the space surrounded by the groove and the lid becomes an internal space, which can be used as a fluid flow path. Such metal structures can be used as heat transfer metal structures. The heat transfer metal structure is placed, for example, in contact with or in close proximity to an object to be heat exchanged, heated or cooled. For example, when heat is to be released from an object, the heat of the object can be released by flowing a cooling medium through the flow path and transmitting heat from the object to the metal body and the cooling medium.

Regarding a metal structure, Patent Document 1 discloses a technique of joining a main body part and a lid part around a lid groove by friction stir welding.

Japanese Patent Application Publication No. 2014-240706

An object of the present invention is to provide a method for manufacturing a metal structure and a metal structure that can secure a degree of freedom in design while suppressing or preventing the occurrence of defects at bonding sites and the complication of the manufacturing process.

The present inventor studied the above-mentioned problems and obtained the following knowledge.

FIGS. 1A and 1B are cross-sectional views schematically showing how the main body part 101 and the lid part 102 are joined by friction stir welding. Note that the cross-sectional view here refers to a cross-sectional view taken on a plane perpendicular to the direction in which the internal space 103 as a fluid flow path extends.

As shown in FIG. 1(a), the distance GD in the horizontal direction between the joint portion of the main body 101 and the lid 102 (the position through which the tip 105a of the tool 105 passes) and the internal space 103 is ensured to be relatively large. Ru. This is because, as shown in FIG. 1(b), if the distance GD is short, the metal base material 103a may enter the internal space 103 during friction stir welding, and there is a risk that defects may occur at the welding site. Therefore, either (i) or (ii) below is required.
(i) The metal structure is designed to ensure a sufficient distance GD.
(ii) A joining method other than friction stir welding is adopted for parts where it is difficult to secure the distance GD.

If a design is made to ensure a sufficient distance GD as in (i) above, for example, it is difficult to arrange the internal spaces 103 densely, and there is a problem that the degree of freedom in designing the metal structure is restricted. arise. On the other hand, as in (ii) above, when friction stir welding and other joining methods are combined, there is a problem that the manufacturing process becomes complicated.

FIGS. 2A and 2B are vertical cross-sectional views schematically showing how the main body part 101 and the lid part 102 are joined by friction stir welding. Note that the vertical cross-sectional view here refers to a cross-sectional view taken on a plane parallel to the direction in which the internal space 103 as a fluid flow path extends. However, since FIGS. 2A and 2B are longitudinal cross-sectional views based on the passing position of the tool 105, the internal space 103 is not shown.

In FIG. 2A, the lid 102 is fitted into a lid groove (not shown) formed in the main body 101. In FIG. The tool 105 of the friction stirring device (not shown) has a cylindrical shape and a thin tip 105a. The tool 105 is inclined with respect to the vertical direction VD so that the tip portion 105a is located further forward in the traveling direction of the tool 105. The inclination angle D (advance angle) is, for example, preferably greater than 0 degrees and less than or equal to 5 degrees, and more preferably greater than or equal to 1 degree and less than or equal to 4 degrees. However, when the tool 105 is moved in the traveling direction PD in a state where the tool 105 has an inclination angle D, the lid portion 102 is deformed in a way that it lifts up in the front in the traveling direction PD, as shown in FIG. 2(b). may occur. The ease of deformation and the amount of deformation increase in proportion to the size (ie, load) of the tool 105. Therefore, when the thickness of the lid part 102 is large, there is a problem that the lid part 102 is easily deformed during friction stir welding, and the tool 105 of the friction stir apparatus is easily damaged. Therefore, it is difficult to employ the lid portion 102 having a large thickness, and the degree of freedom in designing the metal structure may be limited. In addition, when adopting a thick lid part 102, if the tool 105 is enlarged to ensure its mechanical strength, a larger joint area must be secured, which requires further design of the metal structure. Freedom is limited. Further, since measures are required to prevent or suppress deformation of the lid portion 102, a problem arises in that the manufacturing process becomes complicated.

The present inventor completed the present invention based on the above knowledge. As an embodiment of the present invention, the following configuration may be adopted.

(1) A method for manufacturing a metal structure, comprising:
The metal structure includes two metal members that are vertically stacked and joined by friction stir welding,
The two metal members are configured to overlap each other in the vertical direction to form an assembly having an internal space between the two metal members, and the assembly includes the a discontinuous portion configured such that the two metal members are discontinuous by contacting or coming close to each other without being joined to each other at a position exposed to the internal space; At a position not exposed to the internal space, the two metal members are not joined to each other but come into contact with each other or come close to each other, so that the two metal members have a boundary with each other, and are physically connected to the discontinuous part. and a continuous non-bonded part, and the non-bonded part is a part of the two metals at a shallower position than the discontinuous part with respect to the upper surface of the assembly when the assembly is viewed in the vertical direction. The members include upper portions that are not joined to each other and are in contact with or close to each other in the vertical direction, and each of the discontinuous portion and the upper portion surrounds the internal space when the assembly is viewed in the vertical direction. formed in
The manufacturing method includes:
a preparation step of preparing the two metal members;
an assembly step of forming the assembly by overlapping the two metal members in the vertical direction;
The two metal members are joined by inserting the friction stir welding tool from the upper surface of the assembly to the welding depth while rotating and moving it along the upper portion when viewed in the vertical direction. forming a joint part, and the joining part is formed so that the non-joint part remains at an inner position communicating with the internal space via the discontinuous part,
The welding depth is a depth at which the friction stir welding reaches the upper portion but does not reach the depth of the discontinuity.

According to the manufacturing method (1), in the welding step, the tool is inserted into the assembly so that the friction stir welding reaches the upper portion but not the discontinuous portion. The upper portion is located at a shallower position than the discontinuity. Since the joint is formed at a shallow location, the tool is not inserted to a deep location. It is possible to reduce the load applied to the metal structure during welding, and to suppress or prevent the tool for friction stir welding from increasing in size. Deformation of the metal member can be suppressed or prevented. It becomes possible to use thicker metal members. Since the distance between the insertion position of the tool and the internal space can be secured, it is possible to suppress or prevent the metal base material from flowing into the internal space due to friction stir welding. In addition, friction stir welding is performed on the vertically overlapping upper portions of the two metal members to form a joint. Therefore, the occurrence of defects at the joint can be prevented.

As described above, according to the manufacturing method (1), the degree of freedom in designing the metal structure can be increased while preventing the occurrence of defects. Further, according to the manufacturing method (1), since joining can be performed at a shallow position, it is easy to employ friction stir welding. There is no need to combine friction stir welding with other joining methods, and a configuration that can be joined only by friction stir welding can be adopted. However, the joining of the two metal members in the metal structure (1) is not necessarily limited to friction stir welding. Along with friction stir welding, joining methods other than friction stir welding may also be used. By adopting the manufacturing method (1), the degree of freedom in design is improved, it is possible to adopt a structure in which two metal members can be easily joined, and the disadvantages due to the combination of joining methods can be reduced.

(2) The manufacturing method of (1), comprising:
In the bonding step, the bonded portion is formed such that the non-bonded portion has a portion extending in the vertical direction at the inner position.

According to the manufacturing method (2), since the non-joining portion has a portion extending vertically at the inner position, the distance between the discontinuous portion and the joining portion can be ensured in the vertical direction. Therefore, for example, even if a sufficient horizontal distance between the discontinuous portion and the joint portion is not ensured, the distance between the discontinuous portion and the joint portion can be ensured. As a result, it is possible, for example, to arrange the internal spaces more densely. The degree of freedom in design can be improved while suppressing the occurrence of defects and suppressing or preventing complication of the manufacturing process.

(3) The manufacturing method of (1) or (2),
In the joining step, the joining part is formed so that the non-joining part remains not only at the inside position but also at an outside position not communicating with the internal space.

According to the manufacturing method (3), the bonded portion is formed such that the non-bonded portions remain on both sides of the bonded portion (that is, at both the inner and outer positions). The occurrence of voids at the joint can be suppressed or prevented. As a result, it is possible to prevent defects in the metal structure, especially defects in the internal space, to avoid complication of the manufacturing process, and to improve the degree of freedom in designing the metal structure.

Note that since a joint exists between the outer non-joint part (the non-joint part remaining at the outer position) and the internal space, the outer non-joint part does not communicate with the inner space. However, when the metal structure has another internal space, the outer non-bonded part may communicate with the other internal space. The outer non-bonded portion corresponds to the inner non-bonded portion when viewed with respect to the other internal space. Further, the outer non-bonded portion may communicate with the outside of the metal structure.

(4) The manufacturing method according to any one of (1) to (3),
The upper portion is formed to surround the internal space at a position that does not overlap the internal space when the assembly is viewed in the vertical direction,
The discontinuous portion is formed to surround the internal space along an outer periphery of the internal space when the assembly is viewed in the vertical direction.

According to the manufacturing method (4), it is possible to prevent defects in the metal structure, especially defects in the internal space, avoid complicating the manufacturing process, and improve the degree of freedom in designing the metal structure. become.

(5) The manufacturing method according to any one of (1) to (4),
The two metal members are a main body and a lid,
The main body portion has a shoulder portion formed to protrude toward the upper surface of the assembly at a position corresponding to the upper portion when viewed in the vertical direction;
The lid portion has a bottomed groove formed to receive the shoulder portion when the lid portion is overlapped with the main body portion,
The welding depth is a depth at which the friction stir welding reaches the shoulder but does not reach the depth of the discontinuity.

According to the manufacturing method (5), it is possible to prevent defects in the metal structure, especially defects in the internal space, avoid complicating the manufacturing process, and improve the degree of freedom in designing the metal structure. become.

(6) The manufacturing method of (5), comprising:
The main body portion has a lid groove on the surface into which the lid portion is fitted, and the shoulder portion is formed to protrude from the bottom surface of the lid groove toward the upper surface of the assembly,
The lid part has a shape that can be fitted into the lid groove, and the shoulder part is configured to be received in the bottomed groove when the lid part is fitted into the lid groove.

According to the manufacturing method (6), it is possible to prevent defects in the metal structure, especially defects in the internal space, avoid complicating the manufacturing process, and improve the degree of freedom in designing the metal structure. become.

(7) The manufacturing method according to any one of (1) to (6),
The metal structure is a heat transfer metal structure installed so as to be in contact with or close to an object to be heat exchanged, heated or cooled.

According to the manufacturing method (7) above, the degree of freedom in designing the metal structure, particularly the degree of freedom in designing the internal space, can be improved while preventing the occurrence of defects. By using the internal space as a fluid flow path, it is possible to realize, for example, a metal structure in which flow paths with excellent fluid sealing properties are densely arranged. That is, a metal structure having excellent heat conductivity can be realized due to high sealing performance and a degree of freedom in design. That is, according to the manufacturing method (7), a metal structure suitable for heat transfer can be manufactured.

(8) A metal structure according to any one of (1) to (6),
The metal structure is a hollow metal structure used in a state where the internal space is hollow.

According to the manufacturing method (8) above, the degree of freedom in designing the metal structure, particularly the degree of freedom in designing the internal space, can be improved while preventing the occurrence of defects. By making the internal space hollow, for example, a metal structure in which cavities are densely arranged can be realized. That is, it is possible to realize a hollow metal structure with a high degree of freedom in design regarding combinations of mechanical strength, weight, and size of the structure.

(9) A metal structure,
The metal structure is
an internal space provided inside the metal structure;
The two metal parts constituting the metal wall portion defining the internal space are not joined to each other but come into contact with each other or come close to each other at a position where they are exposed to the internal space, so that the two metal parts are discontinuous. a discontinuous portion composed of;
At a position inside the metal structure that is not exposed to the internal space, the two metal parts are not joined to each other but come into contact with each other or come close to each other so that the two metal parts have a boundary, and the discontinuous part an inner non-joining portion formed at an inner position communicating with the internal space via;
a joint part that closes one end of the inner non-joint part so that the boundary between the two metal parts is indistinguishable or difficult to identify at a position inside the metal structure that is not exposed to the internal space;
The joint portion is located in one or substantially one plane and is formed to surround the internal space when viewed in a vertical direction that is perpendicular or substantially perpendicular to the plane,
The discontinuous portion is formed to surround the internal space when viewed in the vertical direction,
The inner non-joining portion has a portion extending in the vertical direction such that the discontinuous portion and the joining portion are located at different heights in the vertical direction.

According to the metal structure (9), it is possible to prevent defects in the metal structure, especially defects in the internal space, avoid complicating the manufacturing process, and improve the degree of freedom in designing the metal structure. can.

(10) The metal structure according to (9),
The metal structure further includes:
At a position inside the metal structure that is not exposed to the internal space, the two metal parts are not joined to each other but come into contact with each other or come close to each other, so that the two metal parts have a boundary, and the internal space It has an outer non-joining part that is located at an outer position where it does not communicate and has one end closed by the joining part.

The metal structure (10) above is manufactured such that the inner non-bonded portion and the outer non-bonded portion are located on both sides of the bonded portion. The generation of voids at the joint during manufacturing can be suppressed or prevented.

(11) The metal structure according to (9) or (10),
The metal structure is a heat transfer metal structure that is placed in contact with or in close proximity to an object to be heat exchanged, heated, or cooled.

According to the metal structure of (11) above, the degree of freedom in designing the metal structure, particularly the degree of freedom in designing the internal space, can be improved while preventing the occurrence of defects. By using the internal space as a fluid flow path, it is possible to realize, for example, a metal structure in which flow paths with excellent fluid sealing properties are densely arranged. That is, a metal structure having excellent heat conductivity can be realized due to high sealing performance and a degree of freedom in design. That is, the metal structure (11) is suitable for heat transfer.

(12) The metal structure according to (9) or (10),
The metal structure is a hollow metal structure used in a state where the internal space is hollow.

According to the manufacturing method (12) above, the degree of freedom in designing the metal structure, particularly the degree of freedom in designing the internal space, can be improved while preventing the occurrence of defects. By making the internal space hollow, for example, a metal structure in which cavities are densely arranged can be realized. That is, it is possible to realize a hollow metal structure with a high degree of freedom in design regarding combinations of mechanical strength, weight, and size of the structure.

According to the present invention, the degree of freedom in design can be ensured while suppressing or preventing the occurrence of defects at the joining site and the complication of the manufacturing process.

FIGS. 1A and 1B are cross-sectional views schematically showing how the main body and the lid are joined by friction stir welding. FIGS. 2A and 2B are cross-sectional views schematically showing how the main body and the lid are joined by friction stir welding. FIG. 3(a) is a plan view schematically showing the metal structure, and FIG. 3(b) is a cross-sectional view taken along the line AA in FIG. 3(a). (a) to (c) are cross-sectional views showing the manufacturing process of the metal structure according to the embodiment. FIG. 3 is a cross-sectional view schematically showing the main body part and the lid part during joining. FIG. 6(a) is a plan view schematically showing a metal structure according to another embodiment, and FIGS. 6(b) to 6(e) are cross-sectional views showing the manufacturing process thereof. This corresponds to the BB line sectional view in a). FIG. 7(a) is a cross-sectional view schematically showing a main body part and a lid part being joined according to a conventional metal structure, and FIG. 7(b) is a sectional view schematically showing a main body part and a lid part being joined according to an embodiment. It is a sectional view showing a part typically. FIGS. 8(a) and 8(b) are cross-sectional views schematically showing conventional metal structures, and FIGS. 8(c) and 8(d) are schematic cross-sectional views of metal structures according to embodiments. FIG. FIG. 7 is a cross-sectional view schematically showing a metal structure according to another embodiment. FIG. 7 is a cross-sectional view schematically showing a method for manufacturing a metal structure according to another embodiment.

<<Metal structure according to one embodiment>>
First, a metal structure 10 according to one embodiment will be described. FIG. 3A is a plan view schematically showing the metal structure 10. FIG. FIG. 3(b) is a cross-sectional view taken along the line AA in FIG. 3(a).

The metal structure 10 has an internal space 3, a discontinuous portion 3c, an inner non-bonded portion 3d, a bonded portion 3f, and an outer non-bonded portion 3h.

The metal structure 10 is a plate-shaped body. As shown in FIG. 3(a), the metal structure 10 has a rectangular shape extending in the longitudinal direction (vertical direction in FIG. 3(a)) in plan view. The metal structure 10 has a rectangular cross-sectional shape, as shown in FIG. 3(b). The metal structure 10 is configured to include a metal portion 1a and a metal portion 2a. The metal portion 1a and the metal portion 2a are joined to each other at a joint portion 3f. The metal structure 10 is made of copper. That is, the metal portion 1a and the metal portion 2a are made of copper. The metal constituting the metal structure 10 is not particularly limited. Examples of the metal include copper, aluminum, or an alloy containing at least one of these. Furthermore, the metal portion 1a and the metal portion 2a may be made of the same metal or may be made of different metals.

Internal space 3 is provided inside metal structure 10 . The internal space 3 has a shape extending in the longitudinal direction (vertical direction in FIG. 3(a)) in plan view. The shape of the internal space is not particularly limited. The internal space may have a U-shape or a zigzag shape. The number of internal spaces in one metal structure is not particularly limited, and is one or more. Internal space 3 is defined by metal wall portion 3b. The metal wall portion 3b is constituted by a portion of the metal structure 10 that is exposed to the internal space 3. The metal wall portion 3b consists of a portion constituted by the metal portion 1a and a portion constituted by the metal portion 2a. The metal portion 1a corresponds to a main body portion 1, which will be described later. The metal portion 2a corresponds to a lid portion 2, which will be described later. The metal portion 1a and the metal portion 2a are integrated by being joined at the joint portion 3f.

The discontinuous portion 3c is configured such that the metal portion 1a and the metal portion 2a are discontinuous because the metal portion 1a and the metal portion 2a are not joined to each other but come into contact with each other or come close to each other at a position where the metal portion 1a and the metal portion 2a are exposed to the internal space 3. This is the part that was The discontinuous portion 3c is formed so as to surround the internal space 3 when viewed in the vertical direction X.

The inner non-bonded portion 3d is a boundary between the metal portion 1a and the metal portion 2a by the metal portion 1a and the metal portion 2a coming into contact or close to each other without being bonded to each other at a position not exposed to the internal space 3 of the metal structure 10. It is formed at an inner position communicating with the internal space 3 via the discontinuous portion 3c. That is, one end 3e of the inner non-joint part 3d is closed by the joint part 3f, and the discontinuous part 3c corresponds to the other end of the inner non-joint part 3d. The inner non-joining portion 3d has a portion extending in the vertical direction X such that the discontinuous portion 3c and the joining portion 3f are located at different heights in the vertical direction X. The inner non-joint part 3d is located inside the joint part 3f. Note that the inner position of the joint portion 3f refers to a position that is relatively close to the inner space 3 and communicates with the inner space 3 via the discontinuous portion 3c. On the other hand, the outer position of the joint portion 3f refers to a position that is relatively far from the inner space 3 and does not communicate with the inner space 3.

The joint portion 3f is a portion that closes one end 3e of the inner non-joint portion 3d so that the boundary between the metal portion 1a and the metal portion 2a is difficult to identify at a position not exposed to the internal space 3 of the metal structure 10. be. Note that it is not necessary to strictly distinguish whether the boundary is unidentifiable or difficult to identify. Fluid can be blocked from flowing in and out between the inner and outer positions of the joint 3f. The joint portion 3f is located within one plane S. The plane S is a virtual plane. The vertical direction X refers to a direction that intersects the plane S perpendicularly or substantially perpendicularly. That is, the joint portions 3f are located at the same or substantially the same height (depth) in the vertical direction X. The plane S may have a width in the vertical direction X. A plane S including the joint portion 3f is included in the metal portion 2a. In other words, the joint portion 3f is formed in the metal portion 2a. Further, the joint portion 3f is formed so as to surround the internal space 3, as shown in FIG. 3(a) when viewed in the vertical direction X.

In the outer non-bonded portion 3h, the metal portion 1a and the metal portion 2a touch or approach each other without being bonded to each other at a position that is not exposed to the internal space 3 of the metal structure 10, so that the metal portion 1a and the metal portion 2a form a boundary. It is located at an outer position, and one end 3g is closed by a joint 3f. The other end of the outer non-joining portion 3h may communicate with the outside of the metal structure 10. When the metal structure 10 has another internal space 3, the other end of the outer non-joining portion 3h may communicate with the other internal space 3. Note that depending on the structure of the metal structure, the outer non-bonded portion may not exist at the outer position.

The internal space 3 communicates with the outside of the metal structure 10 via a through hole 3a formed in the metal portion 2a. As shown in FIG. 3(a), two through holes 3a are formed in the metal portion 2a. The through hole 3a is used, for example, as an inlet or an outlet for a fluid such as a refrigerant. Note that the number of through holes 3a is not particularly limited. The number of through holes 3a may be one or more. Although the through hole 3a is formed only in the metal portion 2a, it may be formed only in the metal portion 1a, or may be formed in both the metal portion 1a and the metal portion 2a.

The through hole 3a is formed in the metal portion 2a. As described above, the joint portion 3f is also formed in the metal portion 2a. In this way, it is preferable that the through hole 3a and the joint part 3f be formed in one metal part 2a and not in the other metal part 1a. This prevents fluid from flowing between the internal space 3 and the outside of the metal structure 10 via the metal portion 1a. For example, when a fluid such as a refrigerant is flowed into the internal space 3, leakage of the fluid from the metal portion 1a is prevented. Therefore, the metal portion 1a can be suitably used as a heat transfer surface that contacts or approaches an object to be heat exchanged, heated or cooled. In this embodiment, the metal portion 1a has a heat transfer surface, but the metal portion 2a may have a heat transfer surface. Further, as shown in FIG. 3(a), the inner space 3 is preferably sealed except for the through hole 3a by forming a joint 3f over the entire outer circumference of the inner space 3. . Note that the through hole 3a is not an essential configuration.

The use of the metal structure 10 is not particularly limited. The metal structure 10 may be, for example, a hollow metal structure used with the interior space 3 being hollow. Further, the metal structure 10 may be a heat transfer metal structure installed so as to be in contact with or close to an object to be heat exchanged, heated, or cooled. The metal structure 10 has an internal space 3 with excellent airtightness. That is, the main body part 1 and the lid part 2 that are joined to each other at the joint part 3f can block fluid from flowing in and out between the internal space 3 and the outside of the metal structure 10. The metal structure 10 can be suitably used so that the internal space 3 functions as a fluid flow path or a reservoir. The fluid is, for example, a gas or a liquid. When the metal structure 10 is used as a heat transfer metal structure, the fluid is, for example, a heat transfer fluid such as a refrigerant.

<<Metal structure manufacturing method according to one embodiment>>
Next, a method for manufacturing the metal structure 10 according to one embodiment will be described with reference to FIGS. 4(a) to 4(c) and FIG. 5.

<Preparation process>
First, in a preparation step, as shown in FIG. 4(a), the main body portion 1 is prepared, and as shown in FIG. 4(b), the lid portion 2 is prepared. The main body portion 1 and the lid portion 2 each correspond to a “metal member”.

The main body portion 1 is made of a metal material. The metal material is not particularly limited as long as it is a metal material that can be plastically flowable by being softened by the frictional heat of friction stirring. Examples of the metal material include copper, aluminum, or an alloy containing at least one of these. The main body portion 1 is a plate-shaped body. The main body portion 1 is an elongated plate-shaped body. The shape of the main body portion 1 is not limited to a plate-shaped body.

The main body 1 has a first defining surface 1d for defining the internal space 3, as shown in FIG. 4(a). In this embodiment, the internal space 3 corresponds to a space within a groove formed in the main body portion 1. The first defining surface 1d corresponds to the surface of a groove formed in the main body portion 1. The internal space 3 is defined by the first defining surface 1d of the main body portion 1 and the second defining surface 2d of the lid portion 2 shown in FIG. 4(b). As shown in FIG. 4(a), a shoulder portion 4 is formed on the outside of the first defining surface 1d.

The lid portion 2 is made of a metal material. The metal material is not particularly limited as long as it is a material that can be plastically flowable by being softened by the frictional heat of friction stirring. Examples of the metal material include copper, aluminum, or an alloy containing at least one of these. The material of the lid part 2 may be the same or substantially the same as the material of the body part 1, or may be different from the material of the body part 1.

The lid part 2 has a second defining surface 2d that defines the internal space 3 together with the first defining surface 1d, as shown in FIG. 4(b). The lid 2 has a contact surface 2b that comes into contact with the outer surface 1b of the main body 1 when the lid 2 is placed on the main body 1, as shown in FIG. 4(d). A bottomed groove 6 for receiving the shoulder portion 4 is formed in the contact surface 2b. The bottomed groove 6 is a bottomed groove. The cross-sectional shape of the bottomed groove 6 is rectangular. In this embodiment, the first definition surface 1d forms a concave portion, and the second definition surface 2d is a flat surface. However, the first defining surface 1d may be a flat surface, and the second defining surface 2d may form a recessed portion. Furthermore, both the first definition surface 1d and the second definition surface 2d may have recesses.

<Assembly process>
In the assembly process, as shown in FIG. 4(c), the lid 2 is placed on the main body 1 so that the shoulder 4 of the main body 1 is received in the bottomed groove 6 of the lid 2. Ru. As a result, an assembly 10a having an internal space 3 is formed. In the assembly 10a, the main body part 1 is located at the bottom and the lid part 2 is located at the top in the vertical direction. The assembly 10a has a discontinuous portion 3c and a non-joint portion 3n. The discontinuous portion 3c is caused by the body portion 1 and the lid portion 2 coming into contact or close to each other without being joined to each other at a position exposed to the internal space 3 of the assembly 10a. It is a part configured to have a boundary of . The non-bonded portion 3n is a portion where the body portion 1 and the lid portion 2 are not joined to each other but come into contact with each other or come close to each other at a position where the body portion 1 and the lid portion 2 are not exposed to the internal space of the assembly 10, so that the body portion 1 and the lid portion 2 have a boundary with each other. It is configured as follows. The non-joining portion 3n is the boundary between the main body portion 1 and the lid portion 2. Similarly, the non-joining portion 3n physically communicates with a discontinuous portion 3c, which is the boundary between the main body portion 1 and the lid portion 2. In the assembly 10a, the non-joining portion 3n includes an upper portion 8. In the upper portion 8, when the assembly 10a is viewed in the vertical direction This is the part that comes into contact with or is close to in the vertical direction X. The upper portion 8 is a portion where the shoulder portion 4 and the bottomed groove 6 overlap in the vertical direction X. The discontinuous portion 3c and the upper portion 8 are formed so as to surround the internal space 3 when the assembly 10a is viewed in the vertical direction X (see FIG. 3(a)).

<Joining process>
The joining process is performed on the assembly 10a, as shown in FIG. In the joining process, the main body part 1 and the lid part 2 are joined by friction stir welding. A tool 5 of a friction stir device (not shown) is used in the joining process. The tool 5 is made of a material with high heat resistance and wear resistance. The tool 5 is a cylindrical body having a tapered tip 5a at the tip. The tool 5 is controlled by a drive device included in the friction stirring device so as to move while rotating. Specifically, the tool 5 can move up and down relative to the main body 1 and the lid 2 and move in parallel relative to the main body 1 and the lid 2 while rotating. The vertical movement is movement in the vertical direction X. Parallel movement is movement in a direction perpendicular to the vertical direction X. A spiral thread groove (not shown) is provided on the outer peripheral surface of the tip 5a of the tool 5.

In the joining process, the tool 5 is inserted into the lid part 2 from the upper surface 2c of the assembly 10a to the joining depth while being rotated. The upper surface 2c of the assembly 10a corresponds to the surface of the lid portion 2 opposite to the contact surface 2b. FIG. 5 shows a state in which the tool 5 is rotated and inserted to the welding depth. The welding depth is the depth at which the friction stir welding depth WD reaches the shoulder portion 4 received in the bottomed groove 6 but does not reach the outer surface 1b (discontinuous portion 3c). In other words, the welding depth is set such that the depth WD of friction stir welding satisfies depth SD≦WD<depth OD. In addition, as shown in FIG. 5, the depth SD is the depth from the upper surface 2c of the lid part 2 to the shoulder part 4. The depth OD is the depth from the top surface 2c of the lid portion 2 to the outer surface 1b (discontinuous portion 3c). At this time, the joint portion 3f is formed so that the non-joint portion 3n remains at an inner position communicating with the internal space 3 via the discontinuous portion 3c. As a result, the non-bonded portion 3n remains as an inner non-bonded portion 3d (see FIG. 3(b)). Furthermore, the non-bonded portion 3n remains as an outer non-bonded portion 3h (see FIG. 3(b)). Note that the width of the shoulder portion 4 (upper portion 8) is not particularly limited, and may be greater than or equal to the width of the tip 5a of the tool 5, or may be less than or equal to the width of the tip 5a of the tool 5. The shoulder portion 4 projects upward from the outer surface 1b, but has a height that does not reach the surface 1s of the main body portion 1.

With the tool 5 being rotated and inserted to the welding depth WD in this manner, the tool 5 is moved along the shoulder portion 4 (see FIG. 3(a)) in plan view. The metal materials at the top of the shoulder portion 4 and the bottom of the bottomed groove 6 are stirred and integrated while being fluidized in a solid state due to frictional heat. Thereby, the top of the shoulder portion 4 and the bottom of the bottomed groove 6 are joined. As a result, the main body portion 1 and the lid portion 2 are joined. Thereby, the metal structure 10 is manufactured by friction stir welding the main body part 1 and the lid part 2. In this embodiment, since the tool 5 does not reach the depth of the internal space 3, the horizontal distance GD between the upper portion 8 (the passing position of the tip 5c of the tool 5) and the internal space 3 can be shortened. The distance GD in this embodiment is shorter than the distance GD in FIG. 1(a).

Note that the method for manufacturing the metal structure 10 may include steps other than the preparation step, assembly step, and bonding step. For example, the method for manufacturing the metal structure 10 may include a step for positioning the main body portion 1 and the lid portion 2 between the assembly step and the bonding step. Positioning may be performed by mechanical means such as clamping means. Positioning may be performed by forming a plurality of friction stir welded joints spaced apart from each other. The joint may be in the form of a dot or a line having a predetermined length. Moreover, in the positioning step, after the plurality of dotted joints are provided, the plurality of linear joints may be provided. Furthermore, after the bonding process, a flattening process may be performed to remove burrs caused by the bonding process. Furthermore, as explained using FIG. 2, the tool 5 may be tilted in the joining process.

<<Other embodiments>>
Next, other embodiments will also be described. FIG. 6(a) is a plan view schematically showing a metal structure 10 according to another embodiment, and FIGS. 6(b) to 6(e) are cross-sectional views showing the manufacturing process thereof. This corresponds to the BB line cross-sectional view in (a). Components that are the same as those included in the embodiments of FIGS. 3 to 5 are given the same reference numerals.

As shown in FIG. 6(a), in the metal structure 10 according to the present embodiment, two lid portions 2 are provided for one main body portion 1. One main body part 1 and two lid parts 2 correspond to "metal members". In this way, the metal structure may be configured to include three or more metal members. Further, in the metal structure 10 according to the present embodiment, one lid part 2 and one main body part 1 are "two metal members joined by friction stir welding in a state in which one lid part 2 and one main body part 1 are stacked vertically". Correspondingly, the other lid part 2 and one main body part 1 correspond to "two metal members joined by friction stir welding in a vertically overlapping state". In this way, the metal structure may have a plurality of combinations corresponding to "two metal members".

As shown in FIG. 6(a), the metal structure 10 is a rectangular plate-shaped body extending in the longitudinal direction (in the vertical direction in the figure). The metal structure 10 has a plurality of (two) internal spaces 3. Each internal space 3 is independent. Each internal space 3 has a shape extending in the longitudinal direction. Each internal space 3 is parallel to each other.

The manufacturing method of this embodiment will be explained using FIGS. 6(a) to 6(e).

First, in a preparation step, one main body part 1 and two lid parts 2 are prepared, as shown in FIGS. 6(a) and 6(b).

The main body part 1 has two lid grooves 7 on the surface 1s of the main body part 1. The lid groove 7 has a shape extending in the longitudinal direction, as shown in FIG. 6(a). The bottom surface of the lid groove 7 corresponds to the outer surface 1b, as shown in FIG. 6(b). A shoulder 4 is formed on the outer surface 1b. As shown in FIGS. 6(a) and 6(b), the shoulder portion 4 is formed along the side edge of the concave groove (inner space 3) and protrudes from the surface of the lid groove 7 (external surface 1b). There is. The bottom surface of the groove corresponds to the first defining surface 1d.

The two lid portions 2 each have a shape that can be fitted into the lid groove 7 as a whole, as shown in FIG. 6(c). The lid portion 2 has a bottomed groove 6 on the contact surface 2b. The contact surface 2b refers to the surface of the lid 2 that comes into contact with the main body 1 when the lid 2 is fitted into the lid groove 7. The bottomed groove 6 has a shape capable of receiving the shoulder portion 4. It is preferable that the bottomed groove 6 is formed so that no gap occurs when the shoulder portion 4 is received.

Next, in the assembly process, each lid 2 is placed on the main body 1 so as to fit into the lid groove 7 of the main body 1, as shown in FIG. 6(d). A plurality of (two) internal spaces 3 are defined by one main body part 1 and two lid parts 2. One internal space 3 is defined for each lid part 2. The numerical relationship among the main body part 1, the lid part 2, and the internal space 3 is not limited to these examples, and can be set as appropriate. As a result, an upper portion 8 is created between the main body portion 1 and the lid portion 2, where the shoulder portion 4 and the bottomed groove 6 overlap in the vertical direction X. The upper portion 8 is located at a shallower position in the vertical direction X than the discontinuous portion 3c.

Next, in the joining step, as shown in FIG. 6(e), friction stir welding is performed on the upper portion 8 to form a joining portion 3f. Friction stir welding reaches the upper portion 8 but does not reach the discontinuous portion 3c.

Through the above steps, a metal structure 10 having two internal spaces 3 is manufactured.

According to this embodiment, a plurality of mutually independent and densely arranged internal spaces can be formed within the metal structure, and a wide degree of freedom in design can be ensured. Furthermore, according to the present embodiment, even when a thick plate-like body is employed as the lid portion 2, a wide degree of freedom in design can be ensured. This point will be explained with reference to FIGS. 7(a) and 7(b).

In FIGS. 7(a) and 7(b), the thickness OD of the lid portion 2 is large. Specifically, the thickness OD is larger than the thickness T of the main body portion 1.

FIG. 7A is a cross-sectional view schematically showing the main body part 1 and the lid part 2 of a conventional metal structure during bonding. The depth into which the tip 5a of the tool 5 is inserted, ie, the welding depth, is set so that the depth WD of friction stir welding satisfies WD≧depth OD. Since the tip 5a of the tool 5 is inserted deeply, there is a risk that the lid portion 2 will be significantly deformed. Furthermore, in order to suppress or prevent a decrease in the airtightness of the internal space 3 due to such deformation, it is necessary to ensure a wide distance GD between the tip 5a of the tool 5 and the internal space 3 in the horizontal direction.

FIG. 7(b) is a cross-sectional view schematically showing the main body part and the lid part during joining according to the embodiment. The welding depth is set such that the depth WD of friction stir welding satisfies depth SD≦WD<depth OD. Since the tip 5a of the tool 5 is not inserted deeply, the risk of large deformation of the lid portion 2 can be reduced or prevented. As a result, the distance GD can be set narrow. In addition to the degree of freedom in designing the internal space, a wide degree of freedom in designing the thickness of the metal member can be ensured.

Next, the shape of the non-bonded portion will be explained using FIGS. 8(a) to 8(d).

FIG. 8(a) is an explanatory diagram of a conventional method for manufacturing a metal structure. FIG. 8(b) is an explanatory diagram of a conventional metal structure. As shown in FIG. 8(a), in the assembly 110a, the contact surface between the main body portion 101 and the lid portion 102 is flat. The tip 105a of the tool 105 is inserted into the lid 102 and reaches the main body 101. After joining, as shown in FIG. 8(b), the discontinuous part 103c, the inner non-joining part 103d, the joining part 103f, and the outer non-joining part 103h are located at the same height.

FIG. 8(c) is an explanatory diagram of the method for manufacturing a metal structure according to the embodiment. FIG. 8(d) is an explanatory diagram of the metal structure according to the embodiment. As shown in FIG. 8(c), in the assembly 10a, the main body portion 1 has a shoulder portion 4. As shown in FIG. The lid part 2 has a bottomed groove 6 for receiving the shoulder part 4. Therefore, the upper portion 8 where the shoulder portion 4 and the bottomed groove 6 overlap in the vertical direction is located at a higher position in the vertical direction X than the discontinuous portion 3c. After bonding, as shown in FIG. 8(d), the inner non-bonded portion 3d and the outer non-bonded portion 3h have portions extending in the vertical direction. Thereby, the joint portion 3f is located at a higher position than the discontinuous portion 3c. As a result, the horizontal distance between the joint 3f and the internal space 3 in FIG. 8(d) is shorter than the horizontal distance between the joint 103f and the internal space 103 in FIG. 8(b).

FIG. 9 is a cross-sectional view schematically showing a metal structure 10 according to another embodiment. The metal structure 10 shown in FIG. 9 has a plurality of internal spaces 3. The main body part 1 has a plurality of shoulder parts 4. The shoulder portion 4 is configured to separate adjacent internal spaces 3. The lid portion 2 has a plurality of bottomed grooves 6. Each bottomed groove 6 is configured to receive a shoulder 4.

In the metal structure 10 shown in FIG. 9, when the central internal space 3 is taken as a reference, an inner non-joining part 3d, a joining part 3f, and an outer non-joining part 3h are successively connected from the upper right discontinuous part 3c, The outer non-joining portion 3h communicates with a discontinuous portion 3c located at the upper left of the right internal space 3. Here, the outer non-joining portion 3h does not communicate with the central internal space 3.

On the other hand, when the right internal space 3 is used as a reference, the inner non-joining part 3d, the joining part 3f, and the outer non-joining part 3h are connected in order from the upper left discontinuous part 3c, and the outer non-joining part 3h is , communicates with a discontinuous portion 3c located at the upper right of the central internal space 3. Here, the outer non-joining portion 3h does not communicate with the right internal space 3.

In this way, the outer non-joining portion 3h when viewed with one internal space 3 as a reference may correspond to the inner non-joining portion 3d when viewing with the adjacent internal space 3 as a reference.

The metal structure 10 shown in FIG. 9 is configured so that adjacent internal spaces 3 are separated only by the shoulder portions 4. Thereby, the metal structure 10 can have a plurality of internal spaces 3 arranged more densely. Higher degrees of design freedom can be achieved.

FIG. 10 is a cross-sectional view schematically showing a method of manufacturing a metal structure 10 according to another embodiment. In the assembly 10a shown in FIG. 10, the upper portion 8 is located higher in the vertical direction X than the discontinuous portion 3c. The upper portion 8 is a portion where the main body portion 1 and the lid portion 2 overlap in the vertical direction. At the inner position of the upper portion 8, the non-joining portion 3n extends downward and communicates with the internal space 3 via the discontinuous portion 3c. On the other hand, at the outer position of the upper portion 8, the non-joining portion 3n extends upward and communicates with the outside of the assembly 3c. The upper part 8 is thus stepped.

In the example shown in FIG. 10, friction stir welding is performed by inserting the tip 5a of the tool 5 into the non-joining portion 3n extending upward together with the upper portion 8. Therefore, in the example shown in FIG. 10, no outer non-joined portion is generated. In this way, an outer non-joint part does not necessarily have to be created. By performing friction stir welding on the stepped upper portion 8, airtightness can be improved. Furthermore, if there is a non-bonded part extending upward as shown in FIG. 10, the airtightness can be further improved by performing friction stir welding so as to leave at least the non-bonded part as an outer non-bonded part. Can be done.

Further, the numerical values, materials, structures, shapes, etc. mentioned in the above embodiments and examples are merely examples, and numerical values, materials, structures, shapes, etc. different from these may be used as necessary.

1 Main body portion 1a Metal portion 1b Outer surface 1d First definition surface 2 Lid portion 2a Metal portion 2b Contact surface 2c Top surface 2d Second definition surface 3 Internal space (recess)
3a Through hole 3b Metal wall 3c Discontinuous part 3d Inner non-joint part 3e One end (of the inner non-joint part) 3f Joint part 3g One end (of the outer non-joint part) 3h Outer non-joint part 3n Non-joint part 4 Shoulder part 5 Tool 5a Tip 6 Bottomed groove 7 Cover groove 10 Metal structure 10a Assembly

Claims (6)

It is a metal structure,
The metal structure is a plate-shaped body and includes a plate-shaped main body and a plate-shaped lid,
Inside the metal structure, an internal space defined by a first defining surface of the plate-like main body and a second defining surface of the plate-like lid;
The plate-like main body and the plate-like lid are not joined to each other but come into contact with each other or come close to each other at a position where the plate-like main body and the plate-like lid are exposed to the internal space, so that the plate-like main body and the plate-like lid are discontinuous. a discontinuous portion composed of;
At a position inside the metal structure that is not exposed to the internal space, the plate-like main body part and the plate-like cover part are not joined to each other but come into contact with each other or come close to each other, so that the plate-like main body part and the plate-like cover part an inner non-joining portion formed at an inner position that is configured to have a boundary and communicating with the internal space via the discontinuous portion;
a joint portion that closes one end of the inner non-joint portion so that the boundary between the plate-like main body portion and the plate-like lid portion is indistinguishable or difficult to identify at a position not exposed to the internal space inside the metal structure; and has
The joint portion is
located in one or substantially one plane at a depth that does not reach either the depth of the discontinuity or the depth of the interior space;
When viewed in a vertical direction that is perpendicular or substantially perpendicular to the plane, a shoulder portion of the plate-like main body portion and a bottomed groove formed in the plate-like lid portion to receive the shoulder portion; are formed in the vertically overlapping upper portions so as to surround the internal space,
The discontinuous portion is formed to surround the internal space when viewed in the vertical direction,
The metal structure, wherein the inner non-joining portion has a portion extending in the vertical direction such that the discontinuous portion and the joining portion are located at different heights in the vertical direction. The metal structure according to claim 1,
The metal structure further includes:
At a position inside the metal structure that is not exposed to the internal space, the plate-like main body part and the plate-like cover part are not joined to each other but come into contact with each other or come close to each other, so that the plate-like main body part and the plate-like cover part 1. A metal structure, characterized in that the metal structure has an outer non-bonded part configured to have a boundary, located at an outer position not communicating with the inner space, and closed at one end by the joined part. The metal structure according to claim 1 or 2,
The plate-shaped main body has an outer surface of the plate-shaped body, the shoulder protruding from the outer surface, and the first defining surface,
The plate-like lid has a contact surface that comes into contact with the outer surface, the bottomed groove formed to receive the shoulder, and the second defining surface. body. The metal structure according to claim 3,
The first definition plane and the second definition plane are
the first definition surface forms a recess, and the second definition surface is a flat surface;
the first defining surface is a flat surface and the second defining surface forms a recess; or
A metal structure, wherein both the first defining surface and the second defining surface have a recess. The metal structure according to claim 1 or 2,
A metal structure, wherein the metal structure is a heat transfer metal structure installed in contact with or close to an object to be heat exchanged, heated, or cooled. The metal structure according to claim 1 or 2,
The metal structure is characterized in that the metal structure is a hollow metal structure used in a state where the internal space is hollow.