CN112975107A

CN112975107A - Method for producing metal structure, and metal structure

Info

Publication number: CN112975107A
Application number: CN202011457197.3A
Authority: CN
Inventors: 柴田尚宪
Original assignee: Keihin Ramtech Co Ltd
Current assignee: Keihin Ramtech Co Ltd
Priority date: 2019-12-13
Filing date: 2020-12-11
Publication date: 2021-06-18
Also published as: KR102453212B1; JP2021094566A; JP7437011B2; TW202122191A; TWI755967B; KR20210075888A; JP2024012566A

Abstract

The present invention relates to a method for manufacturing a metal structure and a metal structure. The invention provides a method for manufacturing a metal structure, which can prevent or inhibit defects in a joint part and complicated manufacturing steps, and can ensure the degree of freedom of design.

Description

Method for producing metal structure, and metal structure

Technical Field

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

Background

A conventional metal structure includes a main body portion and a lid portion. A lid groove is formed in the body portion. A groove is further formed on the bottom surface of the cover groove of the main body part. The cover part is embedded in the cover groove. The body portion at the periphery of the lid groove is engaged with the lid portion. Thus, the space surrounded by the concave groove and the lid portion becomes an internal space, and can be used as a flow path for the fluid. Such a metal structure can be used as a metal structure for heat transfer. The heat transfer metal structure is disposed in contact with or close to an object to be heat-exchanged, heated, or cooled, for example. For example, when heat is released from the object, the cooling medium flows into the flow path, so that heat can be transferred from the object to the metal body and the cooling medium, thereby releasing heat from the object.

Patent document 1 discloses a technique for joining a main body portion and a lid portion at the periphery of a lid groove by friction stir welding with respect to a metal structure.

[ background Art document ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. 2014-240706

Disclosure of Invention

[ problems to be solved by the invention ]

The purpose of the present invention is to provide a method for manufacturing a metal structure and a metal structure, wherein the occurrence of defects in the joint and the complexity of the manufacturing process are suppressed or prevented, and wherein the degree of freedom in design can be ensured.

[ means for solving problems ]

The present inventors have studied the above problems and obtained the following knowledge findings.

Fig. 1(a) and (b) are cross-sectional views schematically showing joining of the body portion 101 and the lid portion 102 by friction stir welding. Here, the cross-sectional view refers to a cross-sectional view taken on a plane orthogonal to a direction in which the internal space 103 serving as a flow path of the fluid extends.

As shown in fig. 1(a), a distance GD in the horizontal direction between the joint portion of the body 101 and the lid 102 (the passing position of the distal end 105a of the tool 105) and the internal space 103 is ensured to be relatively large. 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 a defect may occur in the welded portion. Therefore, either the following (i) or (ii) is required.

(i) The metal structure is designed so that the distance GD is sufficiently ensured.

(ii) A joining method other than friction stir joining is adopted for a portion where it is difficult to secure the distance GD.

As described in (i), when designing to secure a sufficient distance GD, for example, it is difficult to densely arrange the internal space 103, and the degree of freedom in designing the metal structure is limited. On the other hand, when the friction stir welding is combined with another welding method as described in (ii), there is a problem that the manufacturing steps are complicated.

Fig. 2(a) and (b) are vertical sectional views schematically showing the joining of the body portion 101 and the lid portion 102 by friction stir welding. The longitudinal sectional view referred to herein is a sectional view taken on a plane parallel to the direction in which the internal space 103 serving as a flow path of the fluid extends. However, fig. 2(a) and (b) are longitudinal sectional views based on the passing position of the tool 105, and therefore do not show the internal space 103.

In fig. 2a, the lid 102 is fitted into a lid groove (not shown) formed in the body 101. The tool 105 of the friction stir apparatus (not shown) has a cylindrical shape and a thin tip portion 105 a. The tip end 105a of the tool 105 is inclined with respect to the vertical direction VD so as to be positioned further forward in the advancing direction of the tool 105. The inclination angle D (advance angle) is, for example, preferably more than 0 degree and 5 degrees or less, and more preferably 1 degree or more and 4 degrees or less. However, if the tool 105 is moved in the advancing direction PD in a state where the tool 105 has the inclination angle D, the lid section 102 deforms like floating up as shown in fig. 2(b) at the front in the advancing direction PD. The ease of such deformation or the amount of deformation increases in proportion to the size (i.e., load) of the tool 105. Therefore, when the thickness of the lid portion 102 is large, the lid portion 102 is easily deformed at the time of friction stir welding, and the tool 105 of the friction stir welding apparatus is easily broken. Therefore, it is sometimes difficult to use the lid portion 102 having a large thickness, and the degree of freedom in designing the metal structure is limited. In addition, in the case of using the cap 102 having a large thickness, if the tool 105 is increased in size in order to secure the mechanical strength of the tool 105, the joint portion must be secured to be larger, and thus the degree of freedom in designing the metal structure is further limited. Further, since measures for preventing or suppressing deformation of the lid portion 102 are required, there is a problem that the manufacturing process becomes complicated.

The present inventors have completed the present invention based on the knowledge findings described above. As an embodiment of the present invention, the following configuration can be adopted.

(1) A method for manufacturing a metal structure is provided,

the metal structure comprises 2 metal members, the 2 metal members being joined by friction stir joining in a state of being overlapped with each other in a vertical direction,

the 2 metal members are configured to form an assembly having an internal space between the 2 metal members by overlapping each other in the vertical direction, and the assembly includes: a discontinuous portion configured to be discontinuous in the 2 metal members by the 2 metal members coming into contact with or coming close to each other without being joined to each other at a position exposed to the internal space inside the assembly; and a non-joined portion configured to be physically continuous with the non-continuous portion by the 2 metal members contacting or approaching without joining to each other at a position not exposed to the internal space inside the assembly, the 2 metal members having a boundary to each other; the non-joint portion includes an upper portion that is brought into contact with or close to the 2 metal members in the vertical direction without being joined to each other at a position shallower than the non-continuous portion with reference to an upper surface of the assembly when the assembly is viewed from the vertical direction, the non-continuous portion and the upper portion each being formed so as to surround the internal space when the assembly is viewed from the vertical direction,

the manufacturing method comprises:

a preparation step of preparing the 2 metal members;

an assembling step of forming the assembly by overlapping the 2 metal members in the vertical direction; and

a joining step of forming a joined portion for joining the 2 metal members by inserting the friction stir welding tool from an upper surface of the assembly to a joining depth while rotating the friction stir welding tool, and moving the friction stir welding tool along the upper portion when viewed from the vertical direction, the joined portion being formed so as to leave the non-joined portion at an inner position communicating with the internal space via the discontinuous portion;

the joining depth is a depth at which the friction stir joining reaches the upper side portion but does not reach a depth of the discontinuous portion.

According to the manufacturing method of (1), in the joining step, the tool is inserted into the assembly so that the friction stir joining reaches the upper side portion but does not reach the discontinuous portion. The upper portion is located shallower than the discontinuous portion. Since the formation of the engaging portion is performed at a shallow position, a tool is not inserted to a deep position. The load applied to the metal structure at the time of bonding can be reduced, and the increase in size of the tool for friction stir bonding can be suppressed or prevented. Deformation of the metal member can be suppressed or prevented. Metal parts of greater thickness can be used. Since the distance between the insertion position of the tool and the internal space can be ensured, the occurrence of a situation in which the metal base material flows into the internal space due to friction stir welding can be suppressed or prevented. Further, the friction stir welding was performed on the upper side portions of the 2 metal members overlapped in the vertical direction, thereby forming the welded portion. Therefore, defects can be prevented from being generated in the joint portion.

As described above, according to the manufacturing method of (1), the generation of defects can be prevented, and the degree of freedom in designing the metal structure can be improved. In addition, according to the manufacturing method of (1), since the joining can be performed at a shallow position, the friction stir joining can be easily performed. The friction stir welding can be performed by only friction stir welding without combining the friction stir welding with other welding methods. However, the joining of 2 metal members in the metal structure (1) is not necessarily limited to friction stir joining. A joining method other than friction stir joining may also be used together with friction stir joining. By adopting the manufacturing method of (1), the degree of freedom in design is improved, and a structure in which 2 metal members are easily joined can be adopted, and the disadvantages caused by the combination of joining methods can be reduced.

(2) The production process according to (1), wherein

In the joining step, the joining portion is formed in such a manner that the non-joining portion has a portion extending in the vertical direction at the inner position.

According to the manufacturing method of (2), since the non-joint portion has a portion extending in the vertical direction at the inner position, the distance of the discontinuous portion from the joint portion can be ensured in the vertical direction. Therefore, for example, even if the distance in the horizontal direction between the discontinuous portion and the joint portion is not sufficiently secured, the distance between the discontinuous portion and the joint portion can be secured. As a result, for example, the internal space can be more closely configured. The generation of defects can be suppressed, and the complication of the manufacturing steps can be suppressed or prevented, and the degree of freedom of design can be improved.

(3) The production process according to (1) or (2), wherein

In the joining step, the joined portion is formed so that the non-joined portion remains at an outer position not communicating with the internal space in addition to the inner position.

According to the manufacturing method of (3), the joint portion is formed so that the non-joint portion remains on both sides of the joint portion (that is, at two positions of the inner position and the outer position). Generation of voids in the joint portion can be suppressed or prevented. As a result, defects can be prevented from occurring in the metal structure, particularly in the internal space, and complexity of the manufacturing process can be avoided, and the degree of freedom in designing the metal structure can be improved.

Further, since there is a joint portion between the outside non-joint portion (the non-joint portion remaining at the outside position) and the internal space, the outside non-joint portion does not communicate with the internal space. However, in the case where the metal structure has another internal space, the outer non-joined portion may communicate with the other internal space. The outer non-joined portion corresponds to the inner non-joined portion when viewed with reference to the other internal space. The outer non-joined portion may communicate with the outside of the metal structure.

(4) The production process according to any one of (1) to (3), wherein

The upper portion is formed so as to surround the internal space at a position not overlapping with the internal space when the assembly is viewed from the vertical direction,

the discontinuous portion is formed so as to surround the internal space along an outer peripheral edge of the internal space when the assembly is viewed from the vertical direction.

According to the manufacturing method of (4), it is possible to prevent defects from occurring in the metal structure, particularly, in the internal space, and to improve the degree of freedom in designing the metal structure while avoiding the complexity of the manufacturing process.

(5) The production process according to any one of (1) to (4), wherein

The 2 metal parts are a main body part and a cover part,

the body portion has a shoulder portion formed so as to protrude toward the upper surface of the assembly at a position corresponding to the upper portion when viewed from the vertical direction,

the lid portion has a bottomed groove formed so as to receive the shoulder portion when the lid portion is overlapped with the body portion,

the joining depth is a depth at which the friction stir joining reaches the shoulder portion but does not reach a depth of the discontinuity.

According to the manufacturing method of (5), it is possible to prevent defects from occurring in the metal structure, particularly, in the internal space, and to improve the degree of freedom in designing the metal structure while avoiding the complexity of the manufacturing process.

(6) The production process according to (5), wherein

The body portion has a lid groove on a surface thereof into which the lid portion is fitted, and the shoulder portion is formed so as to protrude from a bottom surface of the lid groove toward the upper surface of the assembly,

the lid portion is configured to have a shape that can be fitted in the lid groove, and the shoulder portion is received by the bottomed groove when the lid portion is fitted in the lid groove.

According to the manufacturing method of (6), it is possible to prevent defects from occurring in the metal structure, particularly, in the internal space, and to improve the degree of freedom in designing the metal structure while avoiding the complexity of the manufacturing process.

(7) The production process according to any one of (1) to (6), wherein

The metal structure is a heat-conducting metal structure provided in contact with or close to an object to be heat-exchanged, heated or cooled.

According to the manufacturing method of (7), the occurrence of defects can be prevented, and the degree of freedom in designing the metal structure, particularly the internal space, can be improved. By using the internal space as a fluid flow path, for example, a metal structure in which flow paths having excellent fluid-tightness are densely arranged can be realized. That is, a metal structure having excellent heat conductivity can be realized by high sealing property and design freedom. That is, according to the production method of (7), a metal structure suitable for heat transfer can be produced.

(8) The 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 a cavity.

According to the manufacturing method of (8), the occurrence of defects can be prevented, and the degree of freedom in designing the metal structure, particularly the internal space, can be improved. By providing the internal space as a cavity, for example, a metal structure in which the cavities are densely arranged can be realized. That is, it is possible to realize a hollow metal structure having a high degree of freedom in design in relation to a combination of mechanical strength, weight, and size of the structure.

(9) A metal structure is provided with a metal layer,

the metal structure has:

an internal space provided inside the metal structure;

a discontinuous portion configured such that 2 metal portions constituting a metal wall portion defining the internal space are discontinuous by being brought into contact with or brought close to each other without being joined to each other at a position where the 2 metal portions are exposed to the internal space;

an inner non-joined portion configured to be in contact with or close to the metal structure at a position not exposed to the internal space, the metal structure being formed at an inner position communicating with the internal space via the non-joined portion, the metal structure being formed by the metal parts 2 having a boundary and being not joined to each other; and

a joint portion that closes one end of the inner non-joint portion so that a boundary of the 2 metal portions is not recognizable or is difficult to recognize at a position inside the metal structure that is not exposed to the internal space;

the joint portion is formed in such a manner as to lie in one or substantially one plane and to surround the internal space when viewed from a perpendicular direction which is perpendicular or substantially perpendicular with respect to the plane,

the discontinuous portion is formed so as to surround the internal space when viewed from the vertical direction,

the inner non-joint portion has a portion extending in the vertical direction such that the discontinuous portion and the joint portion are located at different heights in the vertical direction.

According to the metal structure of (9), it is possible to prevent defects from occurring in the metal structure, particularly in the internal space, and to improve the degree of freedom in designing the metal structure while avoiding the complexity of the manufacturing process.

(10) The metal structure according to (9), wherein

The metal structure further includes an outer non-joined portion configured such that the 2 metal portions are not joined to each other and contact or approach each other at a position not exposed to the internal space in the metal structure, the 2 metal portions have a boundary and are located at an outer position not communicating with the internal space, and one end of the outer non-joined portion is closed by the joined portion.

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

(11) The metal structure according to (9) or (10), wherein

According to the metal structure of item (11), it is possible to prevent the occurrence of defects, and to improve the degree of freedom in designing the metal structure, particularly the internal space. By using the internal space as a fluid flow path, for example, a metal structure in which flow paths having excellent fluid-tightness are densely arranged can be realized. That is, a metal structure having excellent heat conductivity can be realized by high sealing property and design freedom. That is, the metal structure of (11) is suitable for heat transfer.

(12) The metal structure according to (9) or (10), wherein

According to the manufacturing method of (12), the occurrence of defects can be prevented, and the degree of freedom in designing the metal structure, particularly the internal space, can be improved. By providing the internal space as a cavity, for example, a metal structure in which the cavities are densely arranged can be realized. That is, it is possible to realize a hollow metal structure having a high degree of freedom in design in relation to a combination of mechanical strength, weight, and size of the structure.

[ Effect of the invention ]

According to the present invention, it is possible to suppress or prevent the occurrence of defects in the bonding portion and the complexity of the manufacturing process, and to ensure the degree of freedom in design.

Drawings

Fig. 1(a) and (b) are cross-sectional views schematically showing joining of the main body portion and the lid portion by friction stir welding.

Fig. 2(a) and (b) are cross-sectional views schematically showing the joining of the main body portion and the lid portion by friction stir welding.

Fig. 3(a) is a plan view schematically showing a metal structure, and fig. 3(b) is a sectional view taken along line a-a of fig. 3 (a).

Fig. 4(a) to (c) are cross-sectional views showing steps of manufacturing the metal structure of the embodiment.

Fig. 5 is a cross-sectional view schematically showing a body portion and a lid portion during joining.

Fig. 6(a) is a plan view schematically showing a metal structure according to another embodiment, and fig. 6(B) to (e) are sectional views showing the manufacturing steps thereof, which correspond to the sectional view taken along line B-B in fig. 6 (a).

Fig. 7(a) is a cross-sectional view schematically showing a body portion and a lid portion in the joining of a conventional metal structure, and fig. 7(b) is a cross-sectional view schematically showing a body portion and a lid portion in the joining according to the embodiment.

Fig. 8(a) and 8(b) are cross-sectional views schematically showing a conventional metal structure, and fig. 8(c) and 8(d) are cross-sectional views schematically showing a metal structure according to an embodiment.

Fig. 9 is a cross-sectional view schematically showing a metal structure according to another embodiment.

Fig. 10 is a cross-sectional view schematically showing a method for manufacturing a metal structure according to another embodiment.

Detailed Description

< metal structure of one embodiment >

First, a metal structure 10 according to an embodiment will be described. Fig. 3(a) is a plan view schematically showing the metal structure 10. Fig. 3(b) is a sectional view taken along line a-a of fig. 3 (a).

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

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

The internal space 3 is provided inside the metal structure 10. The internal space 3 has a shape extending in the longitudinal direction (vertical direction in fig. 3 a) in a plan view. The shape of the internal space is not particularly limited. The inner space may be in a U shape or a zigzag shape. The number of the internal spaces in 1 metal structure is not particularly limited, and is 1 or more. The internal space 3 is defined by a metal wall portion 3 b. The metal wall 3b is formed of a portion of the metal structure 10 exposed to the internal space 3. The metal wall portion 3b includes a portion constituted by the metal portion 1a and a portion constituted by the metal portion 2 a. The metal portion 1a corresponds to the body portion 1 described below. The metal portion 2a corresponds to the lid portion 2 described below. The metal portion 1a and the metal portion 2a are integrated by being joined in a joint portion 3 f.

The discontinuous portion 3c is a portion configured such that the metal portion 1a and the metal portion 2a are discontinuous by being brought into contact with or close to each other without being joined at a position where the metal portion 1a and the metal portion 2a are exposed to the internal space 3. The discontinuous portion 3c is formed so as to surround the internal space 3 when viewed in the vertical direction X.

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

The joint 3f is a portion where one end 3e of the inner non-joint 3d is closed at a position of the metal structure 10 not exposed to the internal space 3 so that the boundary between the metal part 1a and the metal part 2a is not visible or is difficult to be visible. Furthermore, boundaries are not identifiable or difficult to identify without strict differentiation. The entry and exit of the fluid can be blocked between the inner position and the outer position of the engaging portion 3 f. The engaging portion 3f is located in 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 engaging portions 3f are located at the same or substantially the same height (depth) in the vertical direction X. The plane S may also have a width in the vertical direction X. The plane S including the joint 3f is included in the metal portion 2 a. In other words, the engaging portion 3f is formed at the metal portion 2 a. 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.

The outer non-joined portion 3h is a portion configured such that, at a position of the metal structure 10 not exposed to the internal space 3, the metal portion 1a and the metal portion 2a are in contact with or close to each other without being joined to each other, the metal portion 1a and the metal portion 2a have a boundary, the outer non-joined portion 3h is located at an outer position, and one end 3g is closed by a joined portion 3 f. The other end of the outer non-joint portion 3h may communicate with the outside of the metal structure 10. In the case where the metal structure 10 has another internal space 3, the other end of the outer non-joined portion 3h may communicate with the other internal space 3. Further, depending on the structure of the metal structure, there is also a case where the outer non-joined portion does 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 2 a. As shown in fig. 3(a), 2 through holes 3a are formed in the metal portion 2 a. The through-hole 3a is used as an inlet or an outlet of a fluid such as a refrigerant. The number of the through holes 3a is not particularly limited. The number of the through holes 3a may be 1 or more. The through-hole 3a is formed only in the metal portion 2a, but may be formed only in the metal portion 1a, or may be formed in both the metal portion 1a and the metal portion 2 a.

The through-hole 3a is formed in the metal portion 2 a. As described above, the engaging portion 3f is also formed at the metal portion 2 a. In this way, the through-hole 3a and the joint 3f are preferably formed in one metal portion 2a and not in the other metal portion 1 a. This prevents the fluid from flowing between the internal space 3 and the outside of the metal structure 10 through the metal portion 1 a. For example, when a fluid such as a refrigerant flows into the internal space 3, the fluid is prevented from leaking from the metal portion 1 a. Therefore, the metal portion 1a can be suitably used as a heat transfer surface which is brought into contact with or close to an object to be heat-exchanged, heated or cooled. In the present embodiment, the metal portion 1a has a heat transfer surface, but the metal portion 2a may have a heat transfer surface. As shown in fig. 3(a), the internal space 3 is preferably sealed except for the through-hole 3a by forming a joint portion 3f over the entire outer periphery of the internal space 3. The through-hole 3a is not necessarily configured.

The use of the metal structure 10 is not particularly limited. The metal structure 10 may be a hollow metal structure used in a state where the internal space 3 is a cavity, for example. The metal structure 10 may be a heat-conducting metal structure provided in contact with or in proximity to an object to be heat-exchanged, heated, or cooled. The metal structure 10 has an internal space 3 having excellent sealing properties. That is, the body portion 1 and the lid portion 2 joined to each other at the joint portion 3f can block the fluid from entering and exiting 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 flow path or a reservoir for a fluid. 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 a heat transfer fluid such as a refrigerant.

[ method for manufacturing Metal Structure of one embodiment ]

Next, a method for manufacturing the metal structure 10 according to an embodiment will be described with reference to fig. 4(a) to (c) and fig. 5.

< preparation step >

First, in the preparation step, as shown in fig. 4(a), the main body 1 is prepared, and as shown in fig. 4(b), the lid 2 is prepared. The body 1 and the lid 2 correspond to "metal members", respectively.

The main body 1 includes a metal material. The metal material is not particularly limited as long as it is a metal material that can be plastically fluidized by softening with frictional heat of friction stirring. Examples of the metal material include copper, aluminum, and an alloy containing at least one of these. The main body 1 is a plate-like body. The main body 1 is an elongated plate-like body. The shape of the main body 1 is not limited to a plate-like body.

As shown in fig. 4(a), the main body 1 has a first partition forming surface 1d for partitioning and forming the internal space 3. In the present embodiment, the internal space 3 corresponds to a space formed in the groove of the main body 1. The first scribe forming surface 1d corresponds to a surface of a groove formed in the main body 1. The internal space 3 is defined by the first partition forming surface 1d of the body 1 and the second partition forming surface 2d of the lid 2 shown in fig. 4 (b). Outside the first divided surface 1d, a shoulder 4 is formed as shown in fig. 4 (a).

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

As shown in fig. 4(b), the lid portion 2 has a second partition forming surface 2d that partitions the internal space 3 together with the first partition forming surface 1 d. As shown in fig. 4(b), the lid portion 2 has a contact surface 2b that comes into contact with the outer surface 1b of the body portion 1 when the lid portion 2 is placed on the body portion 1. A bottomed groove 6 for receiving the shoulder 4 is formed in the contact surface 2 b. The bottomed tank 6 is a bottomed tank. The sectional shape of the bottomed groove 6 is rectangular. In the present embodiment, the first partition forming surface 1d is a concave portion, and the second partition forming surface 2d is a flat surface. However, the first partition forming surface 1d may be a flat surface and the second partition forming surface 2d may be a concave portion. Further, both the first partition forming surface 1d and the second partition forming surface 2d may have a concave portion.

< Assembly step >

In the assembly step, as shown in fig. 4(c), the lid portion 2 is placed on the body portion 1 so that the shoulder portion 4 of the body portion 1 is received in the bottomed groove 6 of the lid portion 2. Thereby, the assembly 10a having the internal space 3 is formed. In the assembled body 10a, the body 1 is positioned below and the lid 2 is positioned above in the vertical direction. The assembly 10a has a discontinuous portion 3c and a non-joined portion 3 n. The discontinuous portion 3c is a portion configured such that the body portion 1 and the lid portion 2 have a boundary with each other by contact or proximity of the body portion 1 and the lid portion 2 without joining with each other at a position of the assembly 10a exposed to the internal space 3. The non-joined portion 3n is configured such that the main body portion 1 and the lid portion 2 have a boundary with each other by contact or proximity without joining each other at a position of the assembly 10 not exposed to the internal space, and the main body portion 1 and the lid portion 2 are not joined to each other. The non-joint portion 3n is a boundary between the main body 1 and the lid 2. The non-joint portion 3n physically communicates with a discontinuous portion 3c which is similarly a boundary between the body portion 1 and the lid portion 2. In the assembly 10a, the non-joined portion 3n includes the upper portion 8. The upper portion 8 is a portion where the body portion 1 and the lid portion 2 come into contact or approach in the vertical direction X without being joined to each other at a position shallower than the discontinuous portion 3c with reference to the upper surface 2c of the assembly 10a when the assembly 10a is viewed from the vertical direction X. The upper portion 8 is a portion where the shoulder 4 overlaps the bottomed groove 6 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 assembled body 10a is viewed in the vertical direction X (see fig. 3 a).

< bonding step >

As shown in fig. 5, the assembly 10a is subjected to a joining step. In the joining step, the body portion 1 and the lid portion 2 are joined by friction stir joining. A tool 5 of a friction stir welding device (not shown) is used for the joining step. The tool 5 is made of a material having high heat resistance and wear resistance. The tool 5 is a cylindrical body having a tapered tip portion 5a at the tip. The tool 5 is controlled by a driving device provided in the friction stir apparatus so as to move while rotating. Specifically, the tool 5 can perform relative up-down movement with respect to the body 1 and the lid 2 and relative parallel movement with respect to the body 1 and the lid 2 while rotating. The lifting movement is a movement in the vertical direction X. The parallel movement is a 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 distal end portion 5a of the tool 5.

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

In a state where the tool 5 is rotated and inserted to the joining depth WD, the tool 5 is moved along the shoulder 4 (see fig. 3 a) in a plan view. The metal material at the top of the shoulder 4 and the bottom of the bottomed groove 6 is stirred and integrated while flowing in a solid phase by frictional heat. Thereby, the top of the shoulder 4 is engaged with the bottom of the bottomed groove 6. As a result, the body portion 1 and the lid portion 2 are joined. In this way, the metal structure 10 is manufactured by friction stir welding the main body portion 1 and the lid portion 2. In the present embodiment, since the tool 5 does not reach the depth of the internal space 3, the distance GD in the horizontal direction between the upper portion 8 (the passing position of the distal end portion 5c of the tool 5) and the internal space 3 can be shortened. The distance GD in the present embodiment is shorter than the distance GD in fig. 1 (a).

The method of manufacturing the metal structure 10 may include steps other than the preparation step, the assembly step, and the bonding step. For example, the method of manufacturing the metal structure 10 may include a step of positioning the main body portion 1 and the lid portion 2 between the assembling step and the joining step. The positioning may be performed by a mechanical method such as a clamping (clamp) method. The positioning may be performed by forming a plurality of joint portions at intervals by friction stir welding. The joint portion may be in the form of a dot or a line having a specific length. In the positioning step, a plurality of spot-like joint portions may be provided, and then a plurality of linear joint portions may be provided. In addition, after the bonding step, a flattening process for removing burrs generated by the bonding step may also be performed. Further, as described with reference to fig. 2, the tool 5 may be tilted in the joining step.

< other embodiments >

Next, other embodiments will be described. Fig. 6(a) is a plan view schematically showing a metal structure 10 according to another embodiment, and fig. 6(B) to (e) are sectional views showing the manufacturing steps thereof, which correspond to the sectional view taken along line B-B in fig. 6 (a). The same components as those included in the embodiment of fig. 3 to 5 are denoted by the same reference numerals.

As shown in fig. 6(a), in the metal structure 10 of the present embodiment, 2 lid portions 2 are provided for 1 main body portion 1. The 1 main body portion 1 and the 2 lid portions 2 correspond to "metal members". In this way, the metal structure may be configured to include 3 or more metal members. In the metal structure 10 of the present embodiment, one

lid portion

2 and 1 body portion 1 correspond to "2 metal members joined by friction stir welding in a state of being overlapped with each other in the vertical direction", and the

other lid portion

2 and 1 body portion 1 also correspond to "2 metal members joined by friction stir welding in a state of being overlapped with each other in the vertical direction". In this way, the metal structure may have a combination of a plurality of "2 metal members".

As shown in fig. 6(a), the metal structure 10 is a rectangular plate-like body extending in the longitudinal direction (vertical direction in the drawing). The metal structure 10 has a plurality of (2) internal spaces 3. Each internal space 3 is independent. Each internal space 3 has a shape extending in the longitudinal direction. The inner spaces 3 are parallel to each other.

The production method of this embodiment will be described with reference to fig. 6(a) to (e).

First, in the preparation step, as shown in fig. 6(a) and (b), 1

main body portion

1 and 2 lid portions 2 are prepared.

The main body 1 has 2 cover grooves 7 on the surface 1s of the main body 1. As shown in fig. 6(a), the lid groove 7 has a shape extending in the longitudinal direction. As shown in fig. 6(b), the bottom surface of the lid groove 7 corresponds to the outer surface 1 b. A shoulder 4 is formed on the outer side surface 1 b. As shown in fig. 6(a) and (b), the shoulder 4 is formed so as to protrude from the surface (outer surface 1b) of the cover groove 7 along the side edge of the recessed groove (inner space 3). The bottom surface of the groove corresponds to the first scribe forming surface 1 d.

As shown in fig. 6(c), each of the 2 caps 2 has a shape that can be fitted into the cap groove 7 as a whole. The lid portion 2 has a bottom groove 6 on the contact surface 2 b. The contact surface 2b is a surface of the lid portion 2 that contacts the body portion 1 when the lid portion 2 is fitted in the lid groove 7. The bottomed groove 6 has a shape capable of receiving the shoulder 4. The bottomed groove 6 is preferably formed in such a manner that a clearance is generated when the shoulder 4 is received.

Next, in the assembly step, as shown in fig. 6(d), the lid portions 2 are mounted on the body portion 1 so as to be fitted into the lid grooves 7 of the body portion 1, respectively. A plurality of (2) internal spaces 3 are defined by 1

body part

1 and 2 lid parts 2. The inner space 3 is divided into 1 for each cover portion 2. The number of the main body 1, the lid 2, and the internal space 3 is not limited to these examples, and may be set as appropriate. As a result, an upper portion 8 where the shoulder 4 and the bottomed groove 6 overlap in the vertical direction X is generated between the body 1 and the lid 2. The upper portion 8 is located shallower than the discontinuous portion 3c in the vertical direction X.

Next, in the joining step, as shown in fig. 6(e), the joined portion 3f is formed by friction stir joining the upper side portion 8. The friction stir welding reaches the upper portion 8 but does not reach the discontinuous portion 3 c.

Through the above steps, the metal structure 10 having 2 internal spaces 3 is manufactured.

According to the present embodiment, a plurality of internal spaces independently and densely arranged can be formed in the metal structure, and a wide degree of freedom in design can be secured. Further, according to the present embodiment, even when a plate-like body having a large thickness is used as the lid portion 2, a wide degree of freedom in design can be secured. This point will be described with reference to fig. 7(a) and 7 (b).

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

Fig. 7(a) is a cross-sectional view schematically showing a body portion 1 and a lid portion 2 in the conventional joining of metal structures. The depth of insertion of the tip 5a of the tool 5, that is, the joining depth is set so that the depth WD of the friction stir joining satisfies WD ≧ depth OD. Since the tip 5a of the tool 5 is deeply inserted, the lid portion 2 may be largely deformed. In addition, in order to suppress or prevent the decrease in the airtightness of the internal space 3 due to such deformation, it is necessary to secure a wide distance GD between the front end 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 body portion and the lid portion in the joining according to the embodiment. The joining depth is set so that the depth WD of the friction stir joining satisfies the depth SD ≦ WD < the depth OD. Since the front end 5a of the tool 5 is not deeply inserted, the possibility of a large deformation of the cover portion 2 can be reduced or prevented. As a result, the distance GD can be set narrower. Not only with respect to the degree of freedom of design of the internal space but also with respect to the thickness of the metal member, a wide degree of freedom of design can be ensured.

Next, the shape of the non-joined portion will be described with reference to fig. 8(a) to (d).

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

Fig. 8(c) is an explanatory view of the method for manufacturing the metal structure according to the embodiment. Fig. 8(d) is an explanatory view of the metal structure of the embodiment. As shown in fig. 8(c), in the assembled body 10a, the main body 1 has a shoulder 4. The lid portion 2 has a bottomed groove 6 for receiving the shoulder portion 4. Therefore, the upper portion 8 of the shoulder 4, which vertically overlaps the bottomed groove 6, is located higher than the discontinuous portion 3c in the vertical direction X. After the joining, as shown in fig. 8(d), the inner non-joined portion 3d and the outer non-joined portion 3h have portions extending in the vertical direction. Thereby, the engaging portion 3f is located at a position higher than the discontinuous portion 3 c. As a result, the horizontal distance of the joint portion 3f from the internal space 3 in fig. 8(d) is shorter than the horizontal distance of the joint portion 103f from 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 body portion 1 has a plurality of shoulder portions 4. The shoulder 4 is formed to partition the adjacent internal spaces 3. The lid portion 2 has a plurality of bottomed grooves 6. Each bottomed groove 6 is configured to receive the shoulder portion 4.

In the metal structure 10 shown in fig. 9, if the central internal space 3 is used as a reference, the inner non-joined portion 3d, the joined portion 3f, and the outer non-joined portion 3h are connected in this order from the upper right non-continuous portion 3c, and the outer non-joined portion 3h communicates with the upper left non-continuous portion 3c of the right internal space 3. Here, the outer non-joint portion 3h does not communicate with the central internal space 3.

On the other hand, when the right-side internal space 3 is used as a reference, the inner non-joined portion 3d, the joined portion 3f, and the outer non-joined portion 3h are connected in this order from the upper left non-continuous portion 3c, and the outer non-joined portion 3h is connected to the upper right non-continuous portion 3c of the central internal space 3. Here, the outer non-joint portion 3h does not communicate with the right internal space 3.

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

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

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

In the example shown in fig. 10, the friction stir welding is performed by inserting the distal end 5a of the tool 5 into the upper portion 8 and the non-welded portion 3n extending upward. Therefore, in the example shown in fig. 10, the outer non-joined portion is not generated. Thus, the outer non-joint portion does not necessarily have to be created. By performing friction stir welding on the stepped upper portion 8, airtightness can be improved. Further, as shown in fig. 10, when there is a non-joined portion extending upward, the air tightness can be further improved by performing friction stir welding so that at least the non-joined portion remains as an outer non-joined portion.

The numerical values, materials, structures, shapes, and the like recited in the embodiments and examples are merely examples, and numerical values, materials, structures, shapes, and the like different from these may be used as necessary.

[ description of symbols ]

1 main body part

1a metal part

1b outer side surface

1d first divided forming face

2: cover part

2a metal part

2b contact surface

2c upper surface

2d second division forming surface

3 inner space (concave part)

3a through hole

3b Metal wall part

3c discontinuous part

3d inner non-joint part

3e one end (of the inner non-joined part)

3f joint part

3g one end (of the outside non-joined part)

3h outer non-joint part

3n non-joint part

4, shoulder part

5, tools

5a front end portion

6: bottomed tank

7: cover groove

10 metal structure

10a, assembly.

Claims

1. A method for manufacturing a metal structure is provided,

the metal structure includes 2 metal members, the 2 metal members being joined by friction stir joining in a state of being overlapped with each other in a vertical direction,

the 2 metal members are configured to form an assembly having an internal space between the 2 metal members by overlapping each other in the vertical direction, and the assembly includes: a discontinuous portion configured to be discontinuous in the 2 metal members by the 2 metal members coming into contact with or coming close to each other without being joined to each other at a position exposed to the internal space inside the assembly; and a non-joined portion configured to be physically continuous with the non-continuous portion by the 2 metal members contacting or approaching without joining to each other at a position not exposed to the internal space inside the assembly, the 2 metal members having a boundary to each other; the non-joined portion includes an upper portion that is brought into contact with or close to the metal members in the vertical direction without being joined to each other at a position shallower than the discontinuous portion with reference to an upper surface of the assembly when the assembly is viewed from the vertical direction, the discontinuous portion and the upper portion each being formed so as to surround the internal space when the assembly is viewed from the vertical direction,

the manufacturing method comprises:

a preparation step of preparing the 2 metal members;

a joining step of forming a joined portion for joining the 2 metal members by moving the tool for friction stir welding along the upper portion as viewed in the vertical direction until the tool is inserted from the upper surface of the assembly to a joining depth while rotating, the joined portion being formed so that the non-joined portion remains at an inner position communicating with the internal space via the discontinuous portion;

the joining depth is a depth at which the friction stir joining reaches the upper side portion but does not reach the discontinuity.

2. The manufacturing method according to claim 1, wherein

3. The manufacturing method according to claim 1 or 2, wherein

4. The manufacturing method according to any one of claims 1 to 3, wherein

5. The manufacturing method according to any one of claims 1 to 4, wherein

The 2 metal parts are a main body part and a cover part,

the body portion has a shoulder portion formed so as to protrude toward the upper surface of the assembly at a position corresponding to the upper side portion when viewed from the vertical direction,

6. The manufacturing method according to claim 5, wherein

7. The manufacturing method according to any one of claims 1 to 6, wherein

8. The manufacturing method according to any one of claims 1 to 6, wherein

9. A metal structure is provided with a metal layer,

the metal structure has:

an internal space provided inside the metal structure;

a joint portion that closes one end of the inner non-joint portion so that a boundary of the 2 metal portions is not recognizable or difficult to recognize at a position inside the metal structure that is not exposed to the internal space;

10. The metal structure according to claim 9, wherein

The metal structure further includes an outer non-joined portion configured to contact or approach the 2 metal portions without joining each other at a position not exposed to the internal space inside the metal structure, the 2 metal portions have a boundary and are located at an outer position not communicating with the internal space, and one end of the outer non-joined portion is closed by the joined portion.

11. The metal structure according to claim 9 or 10, wherein

12. The metal structure according to claim 9 or 10, wherein