JP7526466B2 - Method for manufacturing metal structure - Google Patents

Description

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

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

Patent Document 1 discloses a technology for forming an internal space in a metal structure by joining a body part and a lid part around a lid groove by friction stir welding. The internal space can be used as a sealed space.

JP 2014-240706 A

The object of the present invention is to provide a method for manufacturing a metal structure that can efficiently form a sealed space with excellent sealing properties and improve the design freedom of the sealed space.

The inventors have investigated the above-mentioned issues and have come to the following findings.

Typically, in friction stir welding, when the joining operation using the tool is completed, the tool is removed from the surface (top) of the material by moving upward while rotating. At this time, a recess may be formed at the removal position due to the removal of the tool. This recess is formed unintentionally. The shape of the recess is not uniform. Therefore, when manufacturing a metal structure having a sealed space by friction stir welding, depending on the shape of the recess, there is a risk that the recess and the internal space will communicate. It is difficult to stably form a sealed space using this method.

To address this issue, a method can be used in which the tool is moved horizontally to the side of the assembly and removed from the side of the assembly. With this method, the tool is not removed from the surface (top surface) of the material, so no recesses are formed. However, in order to remove the tool from the side of the assembly, the tool must move horizontally to the side while avoiding the sealed space. A path for this must be secured. As a result, the layout of the sealed space in the metal structure is restricted. The design freedom of the sealed space is reduced. For example, in a metal structure for heat transfer, the shape of the sealed space is an important factor that affects the efficiency of heat exchange. Therefore, it is preferable to secure the design freedom of the sealed space. Furthermore, if the path of the tool is too long, the time required for manufacturing increases, and manufacturing efficiency decreases.

Therefore, in order to efficiently form a sealed space with excellent sealing properties and to improve the design freedom of the sealed space, it is important to know how to remove the tool upwards so as to ensure sealing properties while keeping the movement of the tool for removal as short as possible.

The present invention has been completed based on the above findings, and can employ the following configurations.
(1) A method for manufacturing a metal structure having at least one sealed space therein, comprising the steps of:
The metal structure includes two metal members that are joined by friction stir welding in a state where the two metal members are overlapped with each other in a vertical direction, and the two metal members are configured to form an assembly having an internal space between the two metal members to become the at least one sealed space by overlapping with each other in the vertical direction,
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;
a sealing process in which a tool for the friction stir welding is inserted into the upper surface of the assembly while rotating, and a joint that joins the two metal members in the vertical direction is formed along a moving path of the tool by moving the tool so that the at least one sealed space is formed between the two metal members;
and an expanding step of moving the tool to form a terminal joint that will be formed when the tool reaches the extraction position before the tool is extracted from the extraction position on the top surface of the assembly, to expand the terminal joint that will be formed when the tool reaches the extraction position.

According to the manufacturing method of (1), the joint is formed so that the terminal joint is expanded. The terminal joint is expanded radially outward from the terminal joint. Therefore, even if the tool is removed upward from the removal position to form a recess at the removal position, the joint can remain around the recess. The remaining joint can prevent or suppress communication between the outside and the inside (e.g., the sealed space) of the metal structure via the recess. Therefore, high sealing performance can be obtained. Furthermore, this makes it possible to remove the tool upward, eliminating the need to secure a path for moving the tool to the side. Therefore, the design freedom of the sealed space can be improved.

As one embodiment, the following aspect can be adopted.
(2) A manufacturing method according to (1), comprising the steps of:
In the expanding step, the tool is moved so that the joint overlaps the entire outer edge of the terminal joint, thereby expanding the terminal joint.

According to the manufacturing method of (2), the terminal joint is expanded so that the joint overlaps the entire outer circumference. This allows the recess and the internal space to be separated more reliably when the tool is removed. This provides a higher level of sealing and allows for greater freedom in designing the sealed space.

As one embodiment, the following aspect can be adopted.
(3) A manufacturing method according to (1) or (2), comprising the steps of:
The expanding step expands the end joint by moving the tool in a loop around the extraction location.

The manufacturing method (3) allows a sealed space with high sealing properties to be formed more efficiently, while also improving the design freedom of the sealed space.

As one embodiment, the following aspect can be adopted.
(4) A manufacturing method according to any one of (1) to (3),
The manufacturing method includes:
The method includes a step of moving the tool to the extraction position located inside the expanded terminal joint portion and extracting the tool from the extraction position.

The manufacturing method (4) provides higher sealing performance and allows for greater freedom in designing the sealed space.

As one embodiment, the following aspect can be adopted.
(5) A manufacturing method according to any one of (1) to (4),
the two metal members have portions that come into surface contact with each other in the vertical direction when the two metal members are stacked on top of each other in the vertical direction,
In the expanding step, the tool passes through the portions that come into surface contact with each other in the vertical direction.

In the manufacturing method of (5), when two metal members are stacked vertically in the assembly process, the portions that make surface contact with each other in the vertical direction abut against each other in the vertical direction due to, for example, gravity and/or a jig, so that the occurrence of gaps can be suppressed or prevented. In the expansion process, a tool passes through the portions that make surface contact with each other in the vertical direction. As a result, the expanded terminal joint includes portions that make surface contact with each other in the vertical direction. Therefore, the occurrence of voids in the expanded terminal joint can be suppressed or prevented. Higher sealing performance can be obtained, and the design freedom of the sealed space can be further improved.

As one embodiment, the following aspect can be adopted.
(6) A manufacturing method according to any one of (1) to (5),
In the expanding step, the tool moves so that the expanded end joint has a distance between it and the sealed space in a plan view.

According to the manufacturing method (6), the expanded terminal joint does not overlap the sealed space in a plan view. By ensuring a distance between the terminal joint and the sealed space, higher sealing performance can be obtained and the design freedom of the sealed space can be further improved.

As one embodiment, the following aspect can be adopted.
(7) The manufacturing method according to any one of (1) to (6),
The sealed space is configured to prevent fluid from passing between the inside and the outside.

The manufacturing method (7) provides high sealing performance and improves the design freedom of the sealed space. It is possible to effectively prevent fluids from entering or exiting the sealed space from the inside and outside.

As one embodiment, the following aspect can be adopted.
(8) A method for producing a semiconductor device according to any one of (1) to (7),
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.

The manufacturing method of (8) can provide high sealing performance and improve the design freedom of the sealed space. By using the sealed space as a fluid flow path, for example, a metal structure can be realized in which flow paths with excellent fluid sealing performance are densely arranged. In other words, a metal structure with excellent heat transfer performance can be realized due to the high sealing performance. In other words, the manufacturing method of (8) can efficiently manufacture a metal structure suitable for heat transfer.

The present invention makes it possible to efficiently form a sealed space with excellent sealing properties and improves the design freedom of the sealed space.

FIG. 1( a ) is a schematic cross-sectional view for explaining a preparation step, FIG. 1( b ) is a schematic cross-sectional view for explaining an assembly step, and FIG. 1( c ) is a schematic cross-sectional view for explaining a sealing step. 2(a) to 2(c) are schematic plan views for explaining the sealing process. FIG. 3A is a plan view that shows a schematic diagram of a state when the tool reaches a removal position in the sealing process, and FIG. 3B is a cross-sectional view thereof. FIG. 4(a) is a plan view that illustrates the expansion step, and FIG. 4(b) is a cross-sectional view thereof. FIG. 5(a) is a plan view that illustrates the expansion step, and FIG. 5(b) is a cross-sectional view thereof. FIG. 6(a) is a plan view that shows the extraction step, and FIG. 6(b) is a cross-sectional view thereof.

A manufacturing method of the metal structure according to the embodiment will be described below. The metal structure according to the embodiment includes a lid portion 2 and a main body portion 1 as two metal members. The main body portion 1 and the lid portion 2 are examples of metal members. In the figure, the vertical direction W is the direction in which the two metal members (the main body portion 1 and the lid portion 2) are overlapped, the direction in which the two metal members are joined, and the direction in which the tool 5 is inserted. The short side direction P corresponds to the short side direction of the rectangular sealed space 3. The long side direction Q corresponds to the long side direction of the rectangular sealed space 3. The short side direction P and the long side direction Q are perpendicular to the vertical direction W, i.e., horizontal directions.

<Preparation process>
First, as shown in FIG. 1(a), in the preparation step, a main body 1 and a cover 2 are prepared.

The main body 1 is a plate-like body having a rectangular cross-sectional shape. The main body 1 is made of metal. The metal constituting the main body 1 is a metal material that can undergo plastic flow by softening due to the frictional heat of frictional stirring. Examples of the metal include copper, aluminum, or an alloy containing at least one of these.

The main body 1 has a recess 1r on the top surface 1u. The recess 1r has a rectangular space in cross section. The recess 1r is configured to receive the lid 2 by fitting the lid 2 into the recess 1r.

A sealed space 3 is formed on the bottom surface 1v of the recess 1r. The sealed space 3 is sealed so as to be liquid-tight by joining the main body 1 and the lid 2. After the main body 1 and the lid 2 are joined, the metal structure is configured so that a fluid is supplied to the sealed space 3 by connecting a fluid injection pipe or a fluid discharge pipe to the through hole 3a described later. Therefore, liquid-tight in this embodiment means that the metal structure is liquid-tight except for the fluid injection port or the fluid discharge port. Therefore, the fluid can pass between the outside of the metal structure and the sealed space at the injection port and the discharge port, but the fluid does not pass between the outside of the metal structure and the sealed space at positions other than the injection port or the discharge port.

The metal structure may or may not have an inlet and/or an outlet connected to the sealed space. The metal structure may be used, for example, with a pipe or the like connected to the inlet and/or the outlet. The metal structure may be used, for example, with a sealing member (such as a plug) provided at the inlet and/or the outlet. The sealed space may be, for example, liquid-tight or airtight. In FIG. 1(a), the space that becomes the sealed space 3 after joining is shown as the sealed space 3. The sealed space 3 is a rectangular space extending in the longitudinal direction Q.

The lid portion 2 is a plate-like body having a rectangular cross-sectional shape. The lid portion 2 is made of metal. The metal constituting the lid portion 2 is a metal material that can undergo plastic flow by softening due to the frictional heat of frictional stirring. Examples of such metals include copper, aluminum, and alloys containing at least one of these. The main body portion 1 and the lid portion 2 may be made of the same metal or different metals. The thickness of the lid portion 2 is the same or substantially the same as the depth of the recess 1r.

<Assembly process>
In the assembly process, as shown in Fig. 1(b), the main body 1 and the lid 2 are overlapped in the vertical direction W. The lid 2 is placed on the main body 1 so that the lid 2 fits into the recess 1r of the main body 1. This forms an assembly 10a having a sealed space 3. The assembly 10a includes two metal members (the main body 1 and the lid 2) that are combined with each other and are not joined. The metal structure is, for example, made of at least two metal members (the main body 1 and the lid 2) that are joined to each other so as to have at least one sealed space 3 therein.

At this time, a boundary 6 is formed between the upper surface 1u of the main body 1 and the upper surface 2u of the lid 2. In addition, the bottom surface 2b of the lid 2 is in surface contact with the bottom surface 1v of the recess 1r in the vertical direction W. This portion is the "portion in surface contact with each other in the vertical direction" 11. The bottom surfaces 1v and 2b are parallel to the horizontal direction at least in the "portion in surface contact with each other in the vertical direction" 11.

Note that the recess 1r does not necessarily have to be formed. The assembly 10a may be constructed by placing the plate-shaped lid 2 on the top surface of the main body 1 where the space that becomes the sealed space 3 is formed and where the recess 1r is not formed. Even in this case, there is a portion between the two metal members that makes surface contact perpendicularly with each other.

<Sealing process>
The sealing process is performed on the assembly 10a as shown in FIG. 1(c). In the sealing process, the body 1 and the cover 2 are joined by friction stir welding. A tool 5 of a friction stir device (not shown) is used in the sealing 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 its tip. The tool 5 is controlled by a drive device provided in the friction stir device so as to move while rotating.

A conventionally known device can be used as the friction stirring device. Specifically, the tool 5 can move up and down relative to the main body 1 and the lid 2, and move horizontally relative to the main body 1 and the lid 2 while rotating. The up and down movement is in the vertical direction W. The horizontal movement is, for example, in the short direction P or the long direction Q. The tip 5a of the tool 5 has a helical screw groove (not shown) on the outer periphery. The assembly 10a is fixed to the main body 1 by a jig (not shown). The lid 2 is fixed to the main body 1 by a jig (not shown).

In the sealing process, the tool 5 is inserted into the upper surface of the assembly 10a while being rotated. The insertion direction of the tool 5 is not particularly limited. For example, the tip 5a of the tool 5 is inserted into the assembly 10a. When the tip 5a of the rotating tool 5 is inserted into the assembly 10a, as shown in FIG. 1(c), a joint 7 is formed not only in the area where the tip 5a is inserted, but also around that area. Therefore, the depth of the joint 7 is greater than the depth to which the tip 5a is inserted. The width of the joint 7 is greater than the diameter of the tip 5a. The tip 5a is inserted so that the joint 7 reaches at least the bottom surface 1v.

The tip 5a is inserted so that it reaches the bottom surface 1v. The depth of the joint 7 is greater than the thickness of the lid 2. The depth of the joint 7 is less than the sum of the thicknesses of the body 1 and the lid 2. In other words, the joint 7 reaches the bottom surface 1v but does not penetrate the body 1. As a result, at the position where the tool 5 has passed, the joint 7 is formed, and the body 1 and the lid 2 are joined.

Next, the horizontal movement of the tool 5 in the sealing process will be described with reference to Figures 2(a) to (c). First, each component in plan view will be described. As shown in Figure 2(a), the main body 1 has a rectangular shape in plan view. More specifically, the main body 1 has a rectangular shape with the longitudinal direction being the vertical direction in the figure.

A recess 1r is formed on the upper surface 1u of the main body 1. In plan view, the recess 1r is a rounded rectangle (oval shape) whose longitudinal direction Q is longer than the lateral direction P. In plan view, the lid 2 is also a rounded rectangle. The lid 2 has a shape and size that allows it to fit into the recess 1r. The main body 1 and the lid 2 overlap in the vertical direction W, so that a portion 11 that makes surface contact with each other in the vertical direction W is formed to surround the entire outer edge of the sealed space 3.

The lid portion 2 has a plurality of through holes 3a. The number of through holes 3a is, for example, two. The through holes 3a are used as inlets or outlets for fluids such as refrigerant for the sealed space 3 described below. The through holes 3a communicate between the outside of the metal structure and the sealed space 3. The through holes may be formed on one of the two surfaces (top surfaces 1u and 2u and the surface opposite thereto) of the metal structure (assembly 10a) facing the vertical direction W, or may be formed on both surfaces. No through holes may be formed.

It is preferable that the through holes are not formed on the surfaces (upper surfaces 1u and 2u) where the tool is not inserted. This maintains the airtightness of the sealed space on the surfaces where the tool is not inserted. This allows the main body 1 to be suitably used as a heat transfer surface that is in contact with or in close proximity to an object to be heat exchanged, heated, or cooled.

Figure 2(a) shows a state where a tool 5 (not shown) is inserted into the insertion position 4 of the assembly 10a. The tool 5 is inserted into the assembly 10a from the boundary 6. A joint 7 is formed at the position where the tool 5 is inserted. The tool 5 moves horizontally along the boundary 6 so as to surround the space that will become the sealed space 3. Figure 2(b) shows the assembly 10a when the tool 5 is moving along the boundary 6. Figure 2(c) shows the assembly 10a when the tool 5 has reached the extraction position 9. In Figures 2(b) and (c), the thick arrows show a schematic representation of the movement path of the tool 5.

The movement path of the tool 5 when it moves horizontally in the sealing process includes, for example, a circular path in plan view that surrounds the space that becomes the sealed space 3, as shown in Figures 2(a) to 2(c). The sealed space 3 can be formed by forming a joint 7 along the movement path. The movement path of the tool 5 in the sealing process includes, for example, a circular path in plan view that surrounds the periphery of the sealed space 3 between the insertion position 4 and the removal position 9.

The path of movement of the tool 5 passes through the entire "portion of vertical surface contact with each other" 11 that surrounds the entire outer periphery of the sealed space 3. In the "portion of vertical surface contact with each other" 11, the occurrence of gaps in the vertical direction can be suppressed or prevented. The tool 5 moves so as to surround the entire outer periphery of the sealed space 3 while following the "portion of vertical surface contact with each other" 11. Around the entire outer periphery of the sealed space 3, the "portion of vertical surface contact with each other" 11 is at least partially joined. As a result, the portion where the two metal members (main body 1 and lid 2) are joined vertically among the "portion of vertical surface contact with each other" 11 is located around the entire outer periphery of the sealed space 3. This provides higher sealing performance.

Figure 3(a) is a plan view that shows the state when the tool 5 reaches the extraction position 9, and Figure 3(b) is a cross-sectional view of the same. In the figure, the extraction position 9 indicates the center position of the tip 5a of the tool 5 in a plan view when the tool 5 is extracted upward. The end joint 8 is formed by the rotation of the tip 5a of the tool 5 located at the extraction position 9.

The terminal joint 8 refers to the joint formed by the rotation of the tool 5 when the tool 5 is located at the extraction position 9. The terminal joint 8 shown in Figures 3(a) and (b) has not yet been expanded. The basic outer edge 8or of the terminal joint 8 shows the outer edge in an unexpanded state. In other words, the basic outer edge 8or corresponds to the outer edge of the joint formed by the rotation of the tool 5 when the tool 5 is located at the extraction position 9. The basic outer edge 8or of the terminal joint 8 is positioned so as to surround the tip 5a of the tool 5 located at the extraction position 9.

In FIG. 3(a), the joint 7 drawn above the basic outer edge 8or of the terminal joint 8 is formed when the tool 5 starts to move from the insertion position 4 (see FIG. 2(a)). On the other hand, the joint 7 drawn below the extraction position 9 is formed just before the tool 5 reaches the extraction position 9 (FIGS. 2(b) and (c)). That is, when the tool 5 reaches the extraction position 9 as shown in FIG. 3(a) and FIG. 3(b), the joint 7 having a ring shape in plan view as shown in FIG. 2(c) is formed to surround the sealed space 3.

Next, the expansion process is performed. The expansion process is performed, for example, after the joint 7 is formed to surround the sealed space 3 in this manner. In the expansion process of this embodiment, the tool 5 first moves a distance R from the extraction position, and then moves in a circle of radius R centered at the extraction position 9 (see Figures 4(a), 4(b), 5(a), and 5(b)).

The circle with radius R centered at the extraction position 9 is an example of a ring surrounding the extraction position. The ring may have any ring shape, such as a perfect circle, an ellipse, or a polygonal ring. In this embodiment, the distance R (radius R) is equal to or less than the diameter of the basic outer edge 8or of the terminal joint 8. Thus, in the expansion process of this embodiment, the terminal joint 8 is expanded by moving the tool 5 so that the joint overlaps the entire circumference of the basic outer edge 8or of the terminal joint 8. The expanded terminal joint 8 includes a "portion that makes surface contact with each other in the vertical direction" 11. The area between the basic outer edge 8or and the expanded outer edge 8ex is an annular area. This area includes a "portion that makes surface contact with each other in the vertical direction" 11. This can further improve the sealing performance.

As shown in FIG. 5(a), the expanded outer edge 8ex of the terminal joint 8 is annular in plan view. The basic outer edge 8or of the terminal joint 8 is also annular in plan view. The expanded outer edge 8ex is expanded radially from the basic outer edge 8or around the entire circumference. The expanded outer edge 8ex is located at a position radially outward from the annular basic outer edge or.

The expansion process in this embodiment ends when the tool 5 draws one revolution of a circle with a radius R centered at the extraction position 9. The number of revolutions is not particularly limited, and may be multiple revolutions. Figures 5(a) and 5(b) show the state at the end of the expansion process.

Next, the extraction process is carried out. In the extraction process of this embodiment, the tool 5 is first returned to the extraction position 9. Next, the tool 5 moves upward from the extraction position 9, thereby extracting the tool 5 from the assembly 10a (metal structure).

According to the manufacturing method of this embodiment, the joint 7 is formed so that the terminal joint 8 is expanded. Therefore, even if the tool 5 is removed upward from the extraction position 9 to form a recess (not shown) at the extraction position 9, the joint 7 (specifically, the expanded terminal joint 8) can remain around the recess.

The remaining joint 7 can prevent or suppress communication between the outside and the inside (e.g., the sealed space 3) of the assembly 10a (metal structure) through the recess. This provides high sealing performance. Furthermore, this allows the tool 5 to be removed upward. This eliminates the need to secure a path for moving the tool 5 to the side of the assembly 10a (metal structure). This improves the design freedom of the sealed space 3.

The present invention is not limited to the above-described embodiment. The following embodiments can be adopted.

In this embodiment, after the tool is moved from the insertion position to the removal position to form a sealed space in the sealing process, an expansion process is performed to expand the terminal joint, and then the tool is returned to the removal position and removed upward from the removal position. However, the order of these operations is not limited to this embodiment. It is necessary that the terminal joint is expanded before the tool is removed upward from the removal position, but the order of the other operations is not particularly limited.

For example, when the insertion position and the removal position are the same, the tool may first be moved in a manner that draws a ring around the insertion position (removal position) at the insertion position to form an expanded terminal joint in advance, and then the tool may be moved to the removal position to form a sealed space, and then the tool may be removed from the removal position.

In this case, when the tool reaches the extraction position, an expanded terminal joint has already been formed. That is, once the tool reaches the extraction position, the expansion and extraction steps may be performed in the order of expansion step followed by extraction step, or the expansion step may be performed before the tool reaches the extraction position. That is, the order of the sealing and expansion steps may be either the sealing step or the expansion step. The sealing, expansion and extraction steps are performed while the tool remains inserted, and the tool is not removed during the process.

When the sealing process, the expansion process, and the extraction process are considered as one set of processes, one or more sealed spaces can be formed by one set of processes. On the other hand, one sealed space can also be formed by multiple sets of processes.

The expansion step is performed consecutively with the sealing step, and it is preferable that the tool insertion depth in the expansion step is the same or substantially the same as the tool insertion depth in the sealing step. Substantially means that deviations due to rotation and movement of the tool are permitted. In the sealing step, it is preferable that the tool movement path includes "portions that make surface contact with each other in the vertical direction" around the entire outer edge of the sealed space, and that in the expansion step, the expanded terminal joint includes "portions that make surface contact with each other in the vertical direction." This can improve the sealability of the sealed space.

In this embodiment, the removal position 9 is the same as the insertion position 4. However, the removal position does not necessarily have to be the same as the insertion position. In this embodiment, the planar annular path that is set to surround the sealed space 3 to form the sealed space 3 includes both the insertion position 4 and the removal position 9. However, the planar annular path does not necessarily have to include the insertion position or the removal position.

The extraction position may be outside the annular path in plan view, i.e., a position farther from the sealed space than the annular path in plan view. In this case, the tool may, for example, move along the annular path in plan view to seal the sealed space, and then move to an extraction position located outside the annular path in plan view, and perform the expansion process at the extraction position. Because the extraction position is located outside the annular path in plan view, the terminal joint can be expanded even if the distance between the annular path in plan view and the sealed space in plan view is relatively short.

The use of the metal structure manufactured by the above-mentioned manufacturing method is not particularly limited. The metal structure may be, for example, a hollow metal structure used in a state where the sealed space 3 is hollow. The metal structure can be suitably used as a heat transfer metal structure that is installed so as to be in contact with or in close proximity to an object to be heat exchanged, heated, or cooled. The metal structure can be suitably used so that the sealed 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 is used as a heat transfer metal structure, the fluid is, for example, a heat transfer fluid such as a refrigerant. The metal structure is not used, for example, as a vehicle component to be mounted on a vehicle. The metal structure is used, for example, in a non-vibration-resistant application. The metal structure is not used, for example, in an environment where it is subject to vibrations caused by an engine or vehicle running.

The metal structure is used, for example, in a vacuum. Note that a vacuum refers to a state of space filled with a gas at a pressure lower than atmospheric pressure. The metal structure is placed so as to be in contact with or in close proximity to an object to be cooled, for example, at 500°C or higher. The metal structure is used, for example, in an atmosphere at 500°C or higher. The metal structure has a sealing property that can prevent leakage of fluid from a sealed space even at 500°C or higher. Therefore, the metal structure can be suitably used as a metal structure for heat transfer in a high-temperature and vacuum environment as described above. The metal structure can be suitably used, for example, as a backing plate. In this case, the object to be cooled can be, for example, a sputtering target.

The manufacturing method of the metal structure may further include the following steps. For example, the manufacturing method of the metal structure may include a temporary joining step between the assembly step and the sealing step. The temporary joining step is a step of performing friction stir welding in a dotted and/or dashed line shape. Before the temporary joining step, the body part 1 and the lid part 2 are not joined. In the sealing step, the body part 1 and the lid part 2 are joined in a line shape. In this way, by performing dotted and/or dashed line joining between the non-joined state and the linearly joined state, deformation can be more effectively prevented or suppressed. In addition, after the sealing step, a flattening process may be performed to remove burrs generated by the sealing step. Furthermore, in the sealing step, the tool 5 may be tilted. In addition, it is also possible to prevent leaks by leaving a columnar protrusion below the extraction position in the same direction as in the present invention and performing the expansion step and extraction step.

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

1 Main body 1r Recess 1u Top surface 1v Bottom surface 2 Lid 2b Bottom surface 2u Top surface 3 Sealed space 3a Through hole 4 Insertion position 5 Tool 5a Tip 6 Boundary 7 Joint 8 End joint 8or Basic outer edge 8ex Extended outer edge 9 Extraction position 10a Assembly 11 Portion in surface contact with each other in the vertical direction

Claims (6)

A method for manufacturing a metal structure having at least one sealed space therein, comprising the steps of:
The metal structure includes two metal members that are joined by friction stir welding in a state where the two metal members are overlapped with each other in a vertical direction , and when the two metal members are overlapped with each other in the vertical direction, the two metal members have portions that are in surface contact with each other in the vertical direction, and are configured to form an assembly having an internal space between the two metal members to become the at least one sealed space by being overlapped with each other in the vertical direction,
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;
a sealing process in which a tool for the friction stir welding is inserted into the upper surface of the assembly while rotating, and a joint that joins the two metal members in the vertical direction is formed along a moving path of the tool by moving the tool so that the at least one sealed space is formed between the two metal members;
an expansion process, before removing the tool from an extraction position on the top surface of the assembly, to form a terminal joint that will be formed when the tool reaches the extraction position , the tool is moved to form the joint so as to expand the terminal joint, and as the tool moves, the tool passes through a portion where the two metal members make surface contact with each other in the vertical direction, thereby expanding the terminal joint so that the terminal joint includes the portion where the two metal members make surface contact with each other in the vertical direction, and enabling the expanded terminal joint to remain around the recess even when a recess is formed at the extraction position when the tool is removed;
an extraction step of moving the tool to the extraction position located inside the expanded end joint portion so that the expanded end joint portion remains around the recessed portion even if a recessed portion is formed at the extraction position by the extraction of the tool, and extracting the tool from the extraction position;
The present invention is characterized by comprising: The method according to claim 1,
In the expanding step, the tool is moved so that the joint overlaps the entire outer edge of the terminal joint, thereby expanding the terminal joint. The method according to claim 1 or 2,
The expanding step expands the end joint by moving the tool in a loop around the extraction location. The method according to any one of claims 1 to 3 ,
In the expanding step, the tool moves so that the expanded end joint has a distance between it and the sealed space in a plan view. The method according to any one of claims 1 to 4 ,
The sealed space is configured to prevent fluid from passing between the inside and the outside. The method according to any one of claims 1 to 5 ,
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.

Images