Method for manufacturing joined body, joined body, and aluminum hollow member for battery case

Abstract

To provide a method for manufacturing a joined body by friction stir welding without deviating a joining locus from a target, and to provide the joined body and an aluminum hollow member for a battery case.SOLUTION: The method for manufacturing a joined body includes an arrangement step and a joining step. In the arrangement step, a plurality of members to be joined are arranged side by side so as to be in contact with each other. In the welding process, the rotating tool 10 is pressed and advanced in the welding direction to weld the members to be welded by friction stirring. On at least one of the plurality of members to be joined, a projecting part 201 is formed in parallel with the joining direction. The member to be welded on which the convex portion is formed is disposed such that the friction stir welding tool is pressed against the member to be welded. The convex portion is disposed so as to be in contact with the side where the welding direction and the rotation direction of the tool coincide with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a joined body, a joined body, and an aluminum hollow member for a battery case. [Background technology]

[0002] Friction stir welding is a technique for joining parts to be welded using a cylindrical tool with a protrusion at the tip. Specifically, a friction stir welding device rotates the tool while pressing it against the parts to be welded. The tool softens the parts to be welded with frictional heat and kneads the area around the joint, joining the parts together. Friction stir welding does not require the preparation of a special environment or pre-treatment of the parts to be welded, and has been attracting attention in recent years as an energy-saving joining method.

[0003] Friction stir welding is generally performed using highly rigid processing machines, but these machines are expensive. By using cheaper robots for friction stir welding, costs can be reduced. However, friction stir welding using robots is prone to deviating from the intended welding trajectory due to insufficient rigidity, resulting in reduced welding strength.

[0004] Patent Document 1 discloses a friction stir welding device equipped with a rotational vibration suppression mechanism that suppresses meandering caused by rotational wobble by clamping the spindle housing without interfering with the progress of the welding tool via a progress assist member and continuously restricting the lateral movement range. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-020192 Summary of the Invention [Problem to be solved by the invention]

[0006] The friction stir welding device disclosed in Patent Document 1 uses a rotational vibration suppression mechanism to clamp the spindle housing and continuously limit the lateral movement range, thereby suppressing meandering of the welding tool. However, the guide member that constitutes the rotational vibration suppression mechanism may shift from the intended position during installation. As a result, there is a problem that the intended welding point may not be aligned with the actual welding point.

[0007] In view of the above-mentioned problems, an object of the present disclosure is to provide a method for manufacturing a welded body that is friction stir welded without deviation of the welding trajectory from the target. [Means for solving the problem]

[0008] A method for manufacturing a welded body according to one aspect of the present disclosure includes an arrangement step and a joining step. In the arrangement step, a plurality of workpieces to be welded are arranged side by side so as to be in contact with each other. In the joining step, a rotating friction stir welding tool is pressed against the workpieces and moved in the welding direction to weld the workpieces by friction stir welding. A convex portion is formed parallel to the welding direction on at least one of the plurality of workpieces to be welded. The workpieces with the convex portion formed are arranged so that the friction stir welding tool can be pressed against them. The convex portion is arranged so as to be in contact with the side of the friction stir welding tool where the welding direction and rotation direction coincide.

[0009] In the above manufacturing method, the arranging step may include arranging the two workpieces in parallel so that they are in contact with each other to form a surface, and the surface may have a tangent line where the two workpieces are in contact. In this case, the convex portion is arranged on one of the two workpieces whose welding direction and rotation direction are the same as those of the tangent line, and is formed at a distance from the tangent line based on the diameter of the friction stir welding tool.

[0010] The manufacturing method may further include a cutting step of cutting the bonded trace after the bonding step. In this case, the cutting step removes the protrusion.

[0011] A welded body according to one aspect of the present disclosure includes a plurality of workpieces welded by friction stir welding. One surface of the welded body has a weld line formed by friction stir welding and a cutting mark including the weld line. The cutting mark has a matching side, where the welding direction and rotation direction in friction stir welding are the same, and an opposing side, where the welding direction and rotation direction in friction stir welding are opposite, on either side of the weld line. With respect to the weld line as the reference, the width of the cutting mark on the matching side is wider than the width of the cutting mark on the opposing side.

[0012] An aluminum hollow member for a battery case according to one embodiment of the present disclosure has a first surface, a second surface, a third surface, a fourth surface, a fifth surface, and a sixth surface. The second surface faces the first surface. The third surface is connected to the first and second surfaces. The fourth surface is connected to the first and second surfaces and faces the third surface. The fifth surface is connected to the first, second, third, and fourth surfaces. The sixth surface is connected to the first, second, third, and fourth surfaces and faces the fifth surface. The aluminum hollow member for a battery case has a convex portion formed on the first surface parallel to the edge, a predetermined distance from the edge connected to the third surface. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide a method for manufacturing a joined body in which friction stir welding is performed without deviation from the intended joining trajectory, a joined body, and an aluminum hollow member for a battery case. [Brief explanation of the drawings]

[0014] [Figure 1] 3A to 3C are perspective views of a manufacturing process of the bonded body according to the first embodiment. [Figure 2] 3A to 3C are cross-sectional views of a bonded body in a manufacturing process according to the first embodiment. [Figure 3] FIG. 10 is a perspective view of a bonded body according to a second embodiment. [Figure 4] FIG. 10 is a perspective view of a hollow aluminum member for a battery case according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present disclosure will be described below through embodiments, but the disclosure according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means for solving the problems. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numerals, and repeated explanations are omitted as necessary.

[0016] <First Embodiment> In the first embodiment, the method for manufacturing a joined body includes an arrangement step and a joining step. In the arrangement step, a plurality of workpieces to be welded are arranged side by side so as to be in contact with each other. Here, a convex portion is formed on at least one of the plurality of workpieces to be welded parallel to the joining direction. The workpieces to be welded with the convex portion formed thereon are arranged so that a friction stir welding tool can be pressed against them. Furthermore, the convex portion is arranged so as to be in contact with the side of the friction stir welding tool whose welding direction and rotation direction coincide with each other. In the joining step, the rotating friction stir welding tool is pressed against the workpieces and advanced in the joining direction to weld adjacent workpieces, that is, a matched side member and an opposing side member, by friction stir welding.

[0017] Next, a method for manufacturing a joined body according to the present disclosure will be described with reference to FIG. 1. FIG. 1 is a perspective view of a manufacturing process of a joined body according to the first embodiment. Here, friction stir welding is used to manufacture the joined body. Friction stir welding is also called FSW (Friction Stir Welding). In FIG. 1, a friction stir welding tool 10, a matching member 20, and an opposing member 30 are used to manufacture the joined body. Specifically, a welding device (not shown) presses the rotating friction stir welding tool 10 and moves it in a welding direction to weld the matching member 20 and the opposing member 30, which are members to be welded, by friction stir welding. Here, the welding device has, for example, an articulated robot arm and can move the tool 10 along a predetermined trajectory. The matching member 20 and the opposing member 30 are each hollow aluminum members.

[0018] The tool 10 is used to join a matching side member 20 and an opposing side member 30. In FIG. 1, the tool 10 moves while rotating clockwise on the surface where the matching side member 20 and the opposing side member 30 meet, with the joining direction facing backward. The tool 10 moves in the joining direction indicated by the solid arrow in FIG. 1. In this way, the tool 10 joins the matching side member 20 and the opposing side member 30. Here, the side whose rotation direction coincides with the joining direction of the tool 10 is called the matching side or AS (Advancing Side). The side whose rotation direction opposes the joining direction is called the opposing side or RS (Retreating Side). Therefore, in FIG. 1, the matching side is on the left side of the joining direction of the tool 10. In addition, in FIG. 1, the opposing side is on the right side of the joining direction of the tool 10.

[0019] During friction stir welding, the tool 10 receives a force in the direction of the white arrow in Fig. 1, i.e., on the matching side, due to friction with the workpieces. Therefore, in a typical manufacturing method using friction stir welding, if the rigidity of the device or robot supporting the tool 10 is not sufficient to withstand the force in the matching side direction, the welding trajectory will curve towards the matching side.

[0020] Next, the matching side component 20 is a component to be welded that is placed on the matching side relative to the tool 10. The matching side component 20 has a convex portion 201 on its top surface so that the tool 10 comes into contact with it. The opposing side component 30 is a component to be welded that is placed on the opposing side relative to the tool 10. The matching side component 20 and the opposing side component 30 are placed side by side so that they come into contact with each other and form a single surface.

[0021] The surface formed by the matching-side component 20 and the opposing-side component 30 has a tangent line where the matching-side component 20 and the opposing-side component 30 meet. In a top view, the tangent line is a straight line indicating the boundary between the matching-side component 20 and the opposing-side component 30. By arranging the matching-side component 20 and the opposing-side component 30 side by side, the matching-side component 20 and the opposing-side component 30 form a tangent line on the surface. The tool 10 moves along the tangent line to join the matching-side component 20 and the opposing-side component 30. The matching-side component 20 and the opposing-side component 30 are made of aluminum, for example. The matching-side component 20 and the opposing-side component 30 may also be made of copper or steel. The matching-side component 20 and the opposing-side component 30 may also be made of different materials. The matching-side component 20 and the opposing-side component 30 do not have to be hollow.

[0022] The protrusion 201 is disposed on the matching side member 20. The protrusion 201 is formed on one surface parallel to the tangent line, at a distance from the tangent line based on the diameter of the friction stir welding tool 10. This allows the protrusion 201 to come into contact with the friction stir welding tool 10, preventing the tool 10 from intruding into the matching side. The protrusion 201 is formed continuously in a direction parallel to the tangent line. In other words, the protrusion 201 is formed continuously from one end to the other end of the matching side member 20 in the tangential direction.

[0023] Referring to FIG. 2, the convex portion 201 of the matching side member 20 is positioned so as to contact the side of the tool 10 where the welding direction and rotation direction are the same. FIG. 2 is a cross-sectional view of a manufacturing process for a welded body according to the first embodiment. In FIG. 2, the tool 10 is welding toward the back and rotating clockwise. The formed convex portion 201 acts as a wall that prevents the tool 10 from entering the matching side, and can prevent the welding trajectory from deviating from the target. Therefore, a method for manufacturing a welded body that can be friction stir welded without deviating from the target welding trajectory can be provided. The tapered portion at the tip of the tool 10 is called a probe.

[0024] There is no particular limitation on the height of the protrusion 201, but if it is too low, it becomes difficult to prevent the friction stir welding tool 10 from penetrating into the mating side. The height of the protrusion 201 necessary to sufficiently prevent the friction stir welding tool 10 from penetrating into the mating side is affected by the diameter of the friction stir welding tool 10, the diameter of the probe, the welding speed, and the like. The height of the protrusion 201 may be, for example, 3 mm or more. Also, the height of the protrusion 201 may be, for example, equal to or greater than the diameter of the probe. Also, the protrusion 201 may be formed to a constant height, or the height may vary in parts.

[0025] If the angle of the side surface of the convex portion 201 relative to the surface of the matching side member 20 is too small, the tool 10 will climb up the side surface of the convex portion 201, making it difficult to prevent the tool 10 from entering the matching side. Therefore, it is desirable that the angle of the side surface of the convex portion 201 be close to 90 degrees relative to the surface of the matching side member 20. Also, the angle of the side surface of the convex portion 201 relative to the surface of the matching side member 20 may exceed 90 degrees.

[0026] In the first embodiment, a method for manufacturing a joined body using friction stir welding in butt joining in which members are aligned side by side has been described. Meanwhile, the method for manufacturing a joined body according to the present disclosure can also be applied to lap joining in which members are stacked on top of one another. In this case, the method for manufacturing a joined body according to the present disclosure can prevent the welding trajectory from deviating from the target by forming a convex portion in the uppermost member to be joined.

[0027] For the sake of explanation, the joining of two members has been described, but the method for manufacturing a joined body according to the present disclosure may also join three or more members in a row. In this case, the opposing member 30 has a convex portion 201 similar to the matching member 20, and an additional member to be joined is disposed adjacent to the opposing member 30 on the opposite side of the matching member 20. In this way, the method for manufacturing a joined body according to the present disclosure can join a plurality of members to be joined in a row.

[0028] <Embodiment 2> Next, a second embodiment of the present disclosure will be described with reference to Fig. 3. Fig. 3 is a perspective view of a bonded body 1 according to the second embodiment. The bonded body 1 is a bonded body that has been manufactured by the manufacturing method described in the first embodiment and then subjected to a cutting process.

[0029] In the cutting step, the bonded trace is cut after the bonding step. In addition, the cutting step removes the convex portion 201. In the cutting step, the removal of the convex portion 201 may be performed in the same operation as the cutting of the bonded trace. In this way, the method for manufacturing a bonded body according to the present disclosure can efficiently manufacture a bonded body without adding an additional step due to the formation of the convex portion 201.

[0030] The welded body 1 is a welded body including a matching side member 21 and an opposing side member 31 joined by friction stir welding. One surface of the welded body 1 has a weld line 4 formed by friction stir welding and a cutting mark 5 including the area of ​​the weld line 4. The weld line 4 corresponds to the tangent line shown in the first embodiment.

[0031] The matching side member 21 is formed by joining the matching side member 20 described in embodiment 1 to the opposing side member 30. The matching side member 21 is formed by cutting the convex portion 201 from the matching side member 20 described in embodiment 1, and a part of the cutting mark 5 is formed at the position where the convex portion 201 was located. The opposing side member 31 is formed by joining the opposing side member 30 described in embodiment 1 to the matching side member 20. The weld line 4 is visible on the surface of the joined body 1 and is the location where the matching side member 21 and the opposing side member 31 are joined by friction stir welding.

[0032] The cutting marks 5 have a matching side where the joining direction and the rotation direction in friction stir welding are the same, and an opposing side where the joining direction and the rotation direction in friction stir welding are opposite, with the joining line 4 in between. The cutting marks 5 are the joining marks and the marks left by cutting the convex portions 201 in the joined body produced by the production method in embodiment 1. The joining marks and the convex portions 201 may be cut in the same process. In this way, the joined body according to the present disclosure is produced by friction stir welding using the convex portions 201 without deviating from the target joining trajectory, without increasing the number of work steps.

[0033] The cutting marks 5 are asymmetric in width on the matching side and the opposing side with respect to the joining line 4 due to cutting of the convex portion 201. More specifically, the width of the cutting marks 5 on the matching side is wider than the width of the cutting marks 5 on the opposing side. The minimum width of the opposing side of the cutting marks 5 is the radius of the tool 10 with respect to the joining line 4. The minimum width of the matching side of the cutting marks 5 is the radius of the tool 10 plus the width of the convex portion 201 with respect to the joining line 4.

[0034] As a result, the joined body according to the present disclosure can be friction stir welded without deviation of the welding trajectory from the target.

[0035] <Third Embodiment> A third embodiment of the present disclosure will be described with reference to FIG. 4. FIG. 4 is a perspective view of an aluminum hollow member 22 for a battery case according to the third embodiment. A plurality of the aluminum hollow members 22 are arranged in parallel and friction stir welded to each other, and are used to manufacture the bottom surface of a battery case, for example. Here, the battery case is, for example, a case for housing a battery for an electric vehicle. Specifically, the aluminum hollow member 22 is the mating member 20 in the first embodiment.

[0036] The hollow aluminum member 22 has a first surface S1, a second surface S2, a third surface S3, a fourth surface S4, a fifth surface S5, and a sixth surface S6. The second surface S2 faces the first surface S1. The third surface S3 connects to the first surface S1 and the second surface S2. The fourth surface S4 connects to the first surface S1 and the second surface S2 and faces the third surface S3. The fifth surface S5 connects to the first surface S1, the second surface S2, the third surface S3, and the fourth surface S4. The sixth surface S6 connects to the first surface S1, the second surface S2, the third surface S3, and the fourth surface S4 and faces the fifth surface S5. The hollow aluminum member 22 has a protrusion 221 formed on the first surface S1 parallel to the edge connected to the third surface S3 at a predetermined distance from the edge.

[0037] The first surface S1 is one surface of the joined body 1 shown in Embodiments 1 and 2. By arranging multiple hollow aluminum members 22 so that the first surface S1 is the top surface and the third surface S3 and fourth surface S4 are adjacent and then friction stir welding them, the method for manufacturing a joined body of the present disclosure can form each surface of a battery case using the hollow aluminum members 22. As a result, the hollow aluminum member for a battery case according to the present disclosure can provide a joined body that is friction stir welded without deviating from the intended welding trajectory. Therefore, using the hollow aluminum member 22 can improve the productivity of battery cases. Note that in the friction stir welding process, two or more hollow aluminum members 22 shown in FIG. 4 may be arranged side by side, or the hollow aluminum member 22 shown in FIG. 4 and the opposing side member 30 shown in FIG. 1 may be arranged side by side.

[0038] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above embodiments and can be modified as appropriate without departing from the spirit of the present disclosure. For example, by stacking multiple plate-shaped members and forming a linear convex portion on the uppermost member, friction stir welding can be performed without deviation from the intended welding trajectory. [Explanation of symbols]

[0039] 1 zygote 4 Joining line 5 Cutting marks 10 Tools 20, 21 Matching side members 22 Aluminum hollow members 30, 31 Opposite side members 201, 221 convex part S1 1st page S2 side 2 S3 3rd page S4 4th page S5 page 5 S6 page 6

Claims

1. an arrangement step of arranging a plurality of workpieces to be joined in a line so as to be in contact with each other; a joining step of pressing a rotating friction stir welding tool against the workpieces and moving it in a joining direction to join the workpieces by friction stir welding, At least one of the plurality of workpieces has a protrusion formed parallel to the joining direction, the workpieces on which the convex portions are formed are arranged so that the friction stir welding tool can be pressed against them, the protrusion is disposed so as to contact a side of the friction stir welding tool where the welding direction and the rotation direction coincide with each other. A method for manufacturing a bonded body.

2. The arranging step includes arranging the two workpieces in parallel so that they contact each other and form one surface, The surface has a tangent line where the two workpieces are in contact, The convex portion is of the two workpieces, it is placed on the workpiece on which the welding direction and the rotation direction coincide with the tangent line, The distance based on the diameter of the friction stir welding tool is formed away from the tangent line. The method for producing the bonded body according to claim 1 .

3. The manufacturing method further includes a cutting step of cutting a joining trace after the joining step, The cutting step removes the protrusion. The method for producing the bonded body according to claim 2 .

4. A welded body including a plurality of welded members joined by friction stir welding, a weld line formed by the friction stir welding and a cutting mark including the weld line on one surface of the welded body; the cutting marks have a matching side where the joining direction and the rotation direction in the friction stir welding are the same, and an opposing side where the joining direction and the rotation direction in the friction stir welding are opposite, across the joining line; A joined body, wherein the width of the cutting mark on the matching side is wider than the width of the cutting mark on the opposing side, based on the joining line.

5. a first surface, a second surface opposite to the first surface, a third surface connected to the first surface and the second surface, a fourth surface connected to the first surface and the second surface and opposite to the third surface, a fifth surface connected to the first surface, the second surface, the third surface, and the fourth surface, and a sixth surface connected to the first surface, the second surface, the third surface, and the fourth surface and opposite to the fifth surface, a protrusion formed on the first surface parallel to an edge connected to the third surface at a predetermined distance from the edge; Aluminum hollow parts for battery cases.

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