Manufacturing method of the bonded body

Abstract

To provide a method for manufacturing a joined body capable of making the finish of the surface of the joined body excellent, as well as, capable of preventing a rotating tool from being damaged.SOLUTION: A method for manufacturing a joined body in which a jacket body (first metal member 2) and a seal body (second metal member 3) are friction stir welded together. In the method: at a main joining step, there is a separation zone in which an end position EP1 is set on the jacket body 2 on an outer side of a set movement route L1, and a first abutted section J1 is friction stir welded, after which a rotating tool F is moved to the end position EP1 and the rotating tool F is separated from the jacket body 2 at the end position EP1; at the main joining step, a stir pin F2 is rotated at a prescribed rotation speed to friction stir weld the first abutted section J1; and in the separation zone, the rotating tool F is moved toward the end position EP1 while gradually lowering the rotation speed thereof from the prescribed rotation speed and the rotating tool F is separated from the jacket body 2.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for producing a bonded body. [Background technology]

[0002] Friction stir welding is used to manufacture welded bodies. Patent Documents 1 to 3 describe methods for manufacturing welded bodies (liquid cooling jackets) by friction stir welding. In Patent Documents 1 to 3, the jacket body is formed using a cast aluminum alloy material such as ADC12, and the seal body is formed using a wrought aluminum alloy material such as A1050, resulting in a combination in which the jacket body is harder than the seal body.

[0003] In Patent Documents 1 to 3, a sealing body is placed on a jacket body, and the butt joint between the jacket body and the sealing body is friction stir welded. In this case, in the removal section after the butt joint is welded, the rotation speed is gradually increased while the stirring pin of the rotary tool F is moved toward an end position set on the sealing body, and the rotary tool is removed from the sealing body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-011271 [Patent Document 2] Japanese Patent Publication No. 2020-131263 [Patent Document 3] Japanese Patent Application Publication No. 2020-175396 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, from the viewpoint of increasing design freedom or reducing manufacturing costs, there is a demand for the rotary tool to be detachable from the jacket body side. For example, when attempting to install an electronic component on the sealed body after joining, the punched hole remaining after the rotary tool is detached hinders the installation of the electronic component, so pre-processing is required to repair the punched hole before installation. In order to perform friction stir welding and install the electronic component without pre-processing, it is necessary to detach the rotary tool from the jacket body side. Alternatively, the sealed body with an electronic substrate installed may be placed on the jacket body and then joined. In this case, too, it is necessary to detach the rotary tool from the jacket body side to avoid contact between the electronic substrate and the rotary tool.

[0006] However, when removing the rotary tool from the jacket body side, which has a high hardness, as described in Patent Documents 1 to 3, if the rotation speed is increased while removing the rotary tool from the jacket body side, excessive heat input to the jacket body occurs. In this case, cracks may occur in the jacket body, a large amount of burrs may occur, and thickness may be reduced, resulting in a poor surface finish of the jacket body. Furthermore, the high hardness of the jacket body may cause significant wear of the rotary tool, which may lead to damage to the rotary tool.

[0007] From this viewpoint, an object of the present invention is to provide a method for manufacturing a bonded body that can improve the finish of the surface of the bonded body and prevent damage to the rotary tool. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a welded body by friction stir welding a first metal member and a second metal member, wherein the first metal member is made of a first aluminum alloy, the second metal member is made of a second aluminum alloy, and the first aluminum alloy is a material type having a higher hardness than the second aluminum alloy, and a rotary tool used for friction stir welding is provided with a stirring pin, and the method includes a butting step of butting a side surface of the first metal member against a side surface of the second metal member to form an butted portion, and a step of inserting the stirring pin of the rotating rotary tool into the second metal member and setting the stirring pin inside the side surface of the second metal member with the outer circumferential surface of the stirring pin slightly in contact with the first metal member. and a main welding process of friction stir welding the butt joint at a predetermined depth along a set movement route set in advance, wherein in the main welding process, an end position is set on the first metal member outside the set movement route, and after friction stir welding the butt joint, the rotary tool is moved to the end position while having a removal section in which the rotary tool is removed from the first metal member at the end position, and in the main welding process, the stirring pin is rotated at a predetermined rotational speed to perform friction stir welding of the butt joint, and in the removal section, the rotary tool is moved toward the end position while gradually decreasing the rotational speed from the predetermined rotational speed to remove the rotary tool from the first metal member.

[0009] In addition, in the main welding step, assuming that the rotational speed during friction stir welding of the butted portions is 100%, it is preferable that the final rotational speed in the separation section is 10% or more and 50% or less.

[0010] Furthermore, in the main joining step, it is preferable that the rotational speed when friction stir welding the butted portions is 5000 rpm or more and 20000 rpm or less, and the final rotational speed in the separation section is 1000 rpm or more and 8000 rpm or less.

[0011] Preferably, the method further comprises a preparation step of forming the first metal member by die casting.

[0012] Furthermore, in the main joining process, it is preferable that a start position is set on the set movement route, and before friction stir welding of the butt joint, the stirring pin is inserted into the start position and the rotary tool is moved and lowered from the start position in a push-in section, and in the main joining process, before the rotary tool is released from the first metal member at the end position, the rotary tool is moved so that the stirring pin passes through the start position to perform friction stir welding.

[0013] Furthermore, in the main joining process, it is preferable that a start position is set on the set movement route, and before friction stir welding of the butt joint, the stirring pin is inserted into the start position and the rotary tool is moved and lowered from the start position in a push-in section, and in the push-in section, the rotary tool is moved and lowered toward an intermediate point set on the set movement route while gradually reducing the rotational speed from a rotational speed higher than the predetermined rotational speed.

[0014] Furthermore, in the main welding process, it is preferable that a start position is set on the second metal member that is inside the set movement route, and before friction stir welding of the butt joint, the stirring pin is inserted into the start position and the rotary tool is moved and lowered from the start position in a push-in section, and in the push-in section, the rotary tool is moved and lowered while gradually reducing the rotational speed from a rotational speed higher than the predetermined rotational speed.

[0015] Furthermore, in the main welding process, it is preferable that a start position is set on the first metal member outside the set movement route, and before friction stir welding of the butt joint, the stirring pin is inserted into the start position and the rotary tool is moved and lowered from the start position in a push-in section, and in the push-in section, the rotary tool is moved and lowered while gradually increasing its rotational speed from a rotational speed lower than the predetermined rotational speed. [Effects of the Invention]

[0016] According to the method for manufacturing a bonded body of the present invention, it is possible to improve the finish of the surface of the bonded body and prevent damage to the rotary tool. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is an exploded perspective view showing a joined body according to an embodiment of the present invention. [Figure 2] 4A to 4C are cross-sectional views showing a butting step in the manufacturing method of the bonded body according to the embodiment. [Figure 3] FIG. 2 is a plan view showing a first region and a second region of the bonded body according to the embodiment. [Figure 4] FIG. 10 is a plan view showing a set movement route of the bonded body according to the embodiment. [Figure 5] FIG. 4 is a plan view showing a starting position of a first main bonding step in the manufacturing method of a bonded body according to the embodiment. [Figure 6] 10 is a schematic diagram showing the insertion depth of a rotary tool at the start position in a first main welding step of the manufacturing method of a bonded body according to the embodiment. FIG. [Figure 7] FIG. 4 is a cross-sectional view showing a first main bonding step in the manufacturing method of the bonded body according to the embodiment. [Figure 8] FIG. 10 is a plan view showing the end position of a first main bonding step in the manufacturing method of a bonded body according to the embodiment. [Figure 9] 10 is a schematic diagram showing the insertion depth of a rotary tool at the end position in a first main welding step of the manufacturing method of a bonded body according to the embodiment. FIG. [Figure 10] FIG. 10 is a plan view showing a second main bonding step in the manufacturing method of the bonded body according to the embodiment. [Figure 11] FIG. 10 is a plan view showing the end position of a second main bonding step in the manufacturing method of a bonded body according to the embodiment. [Figure 12] FIG. 10 is a plan view showing a first main joining step in the method for manufacturing a joined body according to the first modified example. [Figure 13] FIG. 10 is a plan view showing a second main joining step in the method for manufacturing a joined body according to the first modified example. [Figure 14]FIG. 10 is a plan view showing a first main joining step in the method for manufacturing a joined body according to the second modified example. [Figure 15] FIG. 10 is a plan view showing a second main joining step in the method for manufacturing a joined body according to the second modified example. [Figure 16] 10A and 10B are plan views showing a method for manufacturing a bonded body according to a third modified example. [Figure 17] 10A and 10B are plan views showing a method for manufacturing a bonded body according to a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following describes embodiments of the present invention with reference to the accompanying drawings. The present invention is not limited to the following embodiments. Furthermore, some or all of the components in the embodiments and modifications can be combined as appropriate.

[0019] [1. Embodiment] As shown in FIG. 1, the joined body (liquid cooling jacket) 1 according to this embodiment is composed of a jacket body (first metal member) 2 and a sealing body (second metal member) 3. The joined body 1 is a device that cools a heat-generating element placed inside by circulating a fluid therein. The jacket body 2 and the sealing body 3 are integrated by friction stir welding. In the following description, the "front surface" refers to the surface opposite to the "rear surface."

[0020] The jacket body (first metal member) 2 is mainly composed of a bottom portion 10 and a peripheral wall portion 11. The jacket body 2 is not particularly limited as long as it is a metal that can be friction-stirred, but in this embodiment it is formed to mainly contain a first aluminum alloy. The first aluminum alloy is, for example, an aluminum alloy casting material such as JISH5302 ADC12 (Al-Si-Cu system).

[0021] The bottom 10 is a rectangular plate-like member. The peripheral wall 11 is a wall rising from the peripheral edge of the bottom 10 in the shape of a rectangular frame. The bottom 10 and the peripheral wall 11 form a recess 13. A peripheral wall step 12 is formed on the inner peripheral edge of the peripheral wall 11. The peripheral wall step 12 is composed of a step bottom surface 12a and a step side surface (side surface) 12b rising obliquely from the step bottom surface 12a. As shown in FIG. 2, the inclination angle β of the step side surface 12b may be set as appropriate, but in this embodiment, for example, it is set to an angle that is the same as or similar to the inclination angle α of the stirring pin F2 of the rotary tool F shown in FIG. 7.

[0022] The step side surface 12b may be perpendicular to the step bottom surface 12a. Although the jacket body 2 of this embodiment is integrally formed, for example, the peripheral wall portion 11 may be divided and joined together with a sealing member to form an integrated structure.

[0023] The sealing body (second metal member) 3 is a plate-like member that seals the opening of the jacket body 2. The sealing body 3 is not particularly limited as long as it is a metal that can be friction-stirred, but in this embodiment it is formed to mainly contain a second aluminum alloy. The second aluminum alloy is a material that is lower in hardness than the first aluminum alloy. The second aluminum alloy is formed, for example, from an aluminum alloy wrought material such as JIS A1050, A1070, A1100, or A6063.

[0024] Next, a method for manufacturing a bonded body according to this embodiment will be described. In the method for manufacturing a bonded body according to this embodiment, a preparation step, a butting step, and a main bonding step are performed.

[0025] The preparation step is a step of preparing the jacket body 2 and the sealing body 3. There are no particular limitations on the manufacturing methods of the jacket body 2 and the sealing body 3, but the jacket body 2 is molded by, for example, die casting, and the sealing body 3 is molded by, for example, extrusion molding.

[0026] As shown in FIG. 2, the butting process is a process in which the sealing body 3 is placed on the jacket main body 2 and the side surfaces are butted together. In the butting process, the side surface 3c of the sealing body 3 and the step side surface (side surface) 12b of the peripheral wall step portion 12 are butted together to form a first butt joint J1. Because the step side surface 12b is inclined outward, a gap with a V-shaped cross section is formed in the first butt joint J1. The first butt joint J1 is formed in a rectangular shape in a plan view along the periphery of the sealing body 3. Furthermore, the step bottom surface 12a of the peripheral wall step portion 12 and the back surface 3b of the sealing body 3 are butted together to form a second butt joint J2. The thickness of the sealing body 3 may be set as appropriate, but in this embodiment, it is greater than the height dimension of the step side surface 12b.

[0027] As shown in Fig. 3, the region of the first butt joint J1 on one side (upper side in Fig. 3) of the midline X1 set on the sealing body 3 is defined as a first region R1. The region of the first butt joint J1 on the other side (lower side in Fig. 3) of the midline X1 is defined as a second region R2. The midline X1 is a line segment that passes through the middle of the sealing body 3 in the longitudinal direction.

[0028] As shown in FIG. 4, after the sealing body 3 is placed on the jacket body 2, the jacket body 2 and the sealing body 3 in the second region R2 (see FIG. 3) are clamped by three clamps K1 so as to be immovable. In addition, a "set movement route L1" (dash-dotted line) is set inside the first butt joint J1. The set movement route L1 is a movement route of the rotary tool F required to join the first butt joint J1 in the main joining process described below. As will be described later, in this embodiment, the stirring pin F2 of the rotary tool F is slightly brought into contact with the step side surface 12b, so the set movement route L1 is set to be rectangular in plan view inside the side surface 3c.

[0029] 5 and 6, the main welding process is a process of friction stir welding the first butt joint J1 using a rotary tool F. In this embodiment, a first main welding process is performed to join a first region R1 (see FIG. 3) of the first butt joint J1, and a second main welding process is performed to join a second region R2 (see FIG. 3) of the first butt joint J1.

[0030] As shown in Fig. 7, the rotary tool F is composed of a connecting portion F1 and a stirring pin F2. The rotary tool F is made of, for example, tool steel. The connecting portion F1 is a portion that is connected to the rotating shaft of a friction stirring device (not shown). The connecting portion F1 is cylindrical and has a screw hole (not shown) formed therein for fastening a bolt.

[0031] The stirring pin F2 hangs down from the connecting portion F1 and is coaxial with the connecting portion F1. The stirring pin F2 tapers as it moves away from the connecting portion F1. The tip of the stirring pin F2 is provided with a flat surface F3.

[0032] A spiral groove is engraved on the outer circumferential surface of the stirring pin F2. In this embodiment, in order to rotate the rotary tool F clockwise, the spiral groove is formed counterclockwise from the base end to the tip. In other words, the spiral groove is formed counterclockwise when viewed from above when tracing the spiral groove from the base end to the tip.

[0033] When rotating the rotary tool F counterclockwise, it is preferable to form the spiral groove clockwise from the base end to the tip. In other words, in this case, the spiral groove is formed clockwise as viewed from above when tracing the spiral groove from the base end to the tip. By setting the spiral groove in this manner, the metal that has plastically fluidized during friction stirring is guided by the spiral groove to the tip side of the stirring pin F2. This makes it possible to reduce the amount of metal that spills out of the metal members to be joined (the jacket body 2 and the sealing body 3).

[0034] As shown in FIG. 5 , in the first main welding process, friction stir welding is performed continuously through three sections: a push-in section from the start position SP1 to the midpoint S1; a main section from the midpoint S1 to the midpoint S2 on the set movement route L1; and a withdrawal section from the midpoint S2 to the end position EP1. The midpoints S1 and S2 are set at a position where the midpoint X1 intersects with the set movement route L1. The start position SP1 is set at a position on the surface 3a of the sealing body 3, inside the set movement route L1. In this embodiment, the start position SP1 is set at a position where the angle θ1 formed between the line segment connecting the start position SP1 and the midpoint S1 and the set movement route L1 is an obtuse angle. The angle θ1 is not particularly limited as long as it is an obtuse angle, but is preferably 120° or more, more preferably 150° or more, and even more preferably 170° or more, and is preferably less than 180°, and more preferably 175° or less. When the angle θ1 is equal to or greater than the lower limit, the insertion hole provided at the start position SP1 on the surface of the sealing body 3 is provided closer to the outer periphery of the sealing body 3. This makes it possible to prevent the punched hole from interfering with the placement of an electronic component closer to the center on the surface of the sealing body 3. Furthermore, when the angle θ1 is below the upper limit, it becomes easier to avoid contact between the stirring pin F2 and the jacket body 2 when inserting the stirring pin F2.

[0035] In the pushing-in section of the first main joining process, friction stir welding is performed from the start position SP1 to the midpoint S1, as shown in Figure 5. In the pushing-in section, the stirring pin F2 is rotated to the right and inserted into the start position SP1, and then moved to the midpoint S1. During this process, as shown in Figure 6, the stirring pin F2 is gradually pushed in so that it reaches a preset "predetermined depth" at least before reaching the midpoint S1. In other words, the rotating tool F is not allowed to stay in one place, but is gradually lowered while moving along the set movement route L1.

[0036] In the pressing section of the first joining process, the rotational speed of the rotary tool F during friction stir welding may be set as appropriate. However, the rotary tool F may be moved to the intermediate point S1 while gradually decreasing the rotational speed from a rotational speed higher than the rotational speed of the rotary tool F in this section. At this time, when the stirring pin F2 reaches the intermediate point S1, it is preferable to change the rotational speed toward the rotational speed of the rotary tool F in this section so that it becomes the rotational speed of the rotary tool F in this section. Thereby, since the small pressing force in the pressing process can be compensated by the rotational speed, friction stirring can be suitably performed.

[0037] Once it reaches the intermediate point S1, it directly proceeds to the friction stir welding in this section. As shown in FIGS. 5 and 7, in this section, the rotary tool F is moved so that the rotation axis C of the stirring pin F2 and the set movement route L1 overlap. In this embodiment, as shown in FIG. 7, the peripheral wall portion 11 of the jacket body 2 and the surface 3a of the sealing body 3 are separated from the connecting portion F1 of the rotary tool F, and only the stirring pin F2 is set to be inserted into the jacket body 2 and the sealing body 3. Also, in this section, the "predetermined depth" of the stirring pin F2 is set such that the flat surface F3 of the stirring pin F2 slightly contacts the step bottom surface 12a. The "predetermined depth" of the stirring pin F2 may be set as appropriate. For example, it may be set at a position that does not reach the step bottom surface 12a. Here, the contact allowance of the flat surface F3 of the stirring pin F2 with respect to the step bottom surface 12a is defined as the insertion amount D (not shown). When the flat surface F3 of the stirring pin F2 contacts the step bottom surface 12a as in this embodiment, the insertion amount D is set within 0 < D ≦ 1.0 mm, preferably within 0 < D ≦ 0.85 mm, and more preferably within 0 < D ≦ 0.65 mm.

[0038] In this section of the first joining process, as shown in FIG. 7, a set movement route L1 is set such that the outer peripheral surface of the stirring pin F2 slightly contacts the step side surface 12b. Here, the contact allowance between the outer peripheral surface of the stirring pin F2 and the step side surface 12b is defined as an offset amount N. When, as in this embodiment, the flat surface F3 of the stirring pin F2 is inserted deeper than the step bottom surface 12a of the peripheral wall step portion 12 and the outer peripheral surface of the stirring pin F2 is brought into contact with the step side surface 12b, the offset amount N is set within the range of 0 < N ≦ 1.0 mm, preferably within the range of 0 < N ≦ 0.85 mm, and more preferably within the range of 0 < N ≦ 0.65 mm.

[0039] If the outer peripheral surface of the stirring pin F2 and the step side surface 12b are set not to contact each other, the joining strength of the first butting portion J1 will be low. Also, if the offset amount N between the outer peripheral surface of the stirring pin F2 and the step side surface 12b exceeds 1.0 mm, a large amount of the first aluminum alloy of the jacket body 2 may mix into the sealing body 3 side, resulting in possible joining failure. Also, in this section, the rotational speed of the rotary tool F during the friction stir joining of the first butting portion J1 may be set as appropriate. For example, it can be set to 3000 rpm or more and 25000 rpm or less. The rotational speed of the rotary tool F during the friction stir joining of the first butting portion J1 is preferably 5000 rpm or more, more preferably 7000 rpm or more, still more preferably 9000 rpm or more, and preferably 20000 rpm or less, more preferably 17000 rpm or less, still more preferably 15000 rpm or less. The rotational speed of the rotary tool F can be set according to, for example, the materials of the first aluminum alloy and the second aluminum alloy, the thickness of the sealing body 3, and the insertion depth of the stirring pin F2, etc.

[0040] As shown in FIG. 8, when the stirring pin F2 reaches the midpoint S2, it transitions directly to the removal section. In the removal section, as shown in FIG. 9, the stirring pin F2 is gradually moved upward from the midpoint S2 toward the end position EP1, and the stirring pin F2 is removed from the sealing body 3 at the end position EP1. In other words, the rotating tool F is not allowed to remain in one place, but is gradually raised while moving to the end position EP1. At this time, the rotational speed of the rotating tool F in the removal section is gradually reduced compared to the rotational speed of the rotating tool F in this section while the rotating tool F is moved to the end position EP1. For example, if the rotational speed of the rotating tool F when performing friction stir welding of the first butt joint J1 in this section is 100%, the rotational speed in the removal section can be set to 10% or more and 50% or less. Note that the rotational speed in the removal section refers to the final rotational speed reached by the stirring pin F2 when the rotational speed of the rotating tool F is gradually reduced while moving in the removal section. In particular, this refers to the rotational speed reached at the time when the stirring pin F2 is released. The rotational speed in the release section relative to the rotational speed of the rotary tool F when performing friction stir welding of the first butt joint J1 is preferably 15% or more, more preferably 20% or more, even more preferably 25% or more, and preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less. Furthermore, the rotational speed of the rotary tool F in the release section may be set appropriately, for example, to 1000 rpm or more and 8000 rpm or less. The rotational speed of the rotary tool F in the release section is preferably 2000 rpm or more, more preferably 3000 rpm or more, even more preferably 4000 rpm or more, and preferably 7000 rpm or less, more preferably 6000 rpm or less, and even more preferably 5000 rpm or less. By setting the rotational speed of the rotary tool F in the release section to be equal to or greater than the above lower limit, insufficient heat input can be avoided. Therefore, the occurrence of defects due to insufficient heat input can be suppressed. Moreover, by setting the rotation speed of the rotating tool F in the removal section to be equal to or less than the upper limit, excessive heat input can be avoided. Therefore, cracks caused by excessive heat input can be prevented, and burrs and thinning of the material can be suppressed, resulting in a good surface finish.In addition, wear and damage to the rotary tool F can be easily prevented.

[0041] Furthermore, the end position EP1 is set outside the set movement route L1 on the peripheral wall end surface 11a of the peripheral wall portion 11. The end position EP1 is set at a position on the peripheral wall end surface 11a of the peripheral wall portion 11 where the angle θ2 formed by the line segment connecting the end position EP1 and the midpoint S2 and the set movement route L1 is an obtuse angle. A plasticized region W1 is formed on the movement trajectory of the rotating tool F.

[0042] After the first main joining step is completed, the clamps K1 are temporarily released, and as shown in FIG. 10, the jacket body 2 and the sealing body 3 in the first region R1 (see FIG. 3) are clamped immovably by the three clamps K1.

[0043] The second main welding process is a process of friction stir welding the first butt joint J1 in the second region R2 (see FIG. 3). As shown in FIG. 10, in the second main welding process, friction stir welding is performed continuously in three sections: a push-in section from the start position SP2 to the midpoint S3; a main section from the midpoint S3 to the midpoint S4 on the set movement route L1; and a pull-out section from the midpoint S4 to the end position EP2. The start position SP2 is set at a position on the surface 3a of the sealing body 3 that is more inward than the set movement route L1. The midpoint S3 is set on the set movement route L1 closer to the first region R1 (see FIG. 3) than the midpoint S2. In this embodiment, the angle θ3 formed by the line segment connecting the start position SP2 and the midpoint S3 and the set movement route L1 is an obtuse angle.

[0044] In the pushing-in section of the second main joining process, friction stirring is performed from the start position SP2 to the midpoint S3, as shown in Figure 10. In the pushing-in section, the stirring pin F2 is rotated clockwise and inserted into the start position SP2, and then moved to the midpoint S3. During this process, the stirring pin F2 is gradually pushed in so that it reaches a predetermined "predetermined depth" at least by the time it reaches the midpoint S3.

[0045] When the intermediate point S3 is reached, the process moves directly to the main friction stir welding section. In this section, the rotating tool F is moved so that the rotation axis C of the stirring pin F2 overlaps with the set movement route L1. In this section of the second main welding process, friction stir welding is performed in the same manner as in the main section of the first main welding process.

[0046] As shown in Figure 11, when the stirring pin F2 reaches the midpoint S4, it moves directly to the removal section. In the removal section, the stirring pin F2 is gradually moved upward from the midpoint S4 toward the end position EP2, and is removed from the sealing body 3 at the end position EP2. At this time, the rotational speed of the rotating tool F in the removal section is gradually reduced from the rotational speed of the rotating tool F in this section while the rotating tool F is moved to the end position EP1. The conditions of the removal section of the second main welding process are the same as the conditions of the removal section of the first main welding process.

[0047] The end position EP2 is set on the peripheral wall end surface 11a of the peripheral wall portion 11, outside the set movement route L1. In other words, the end position EP2 is set at a position on the peripheral wall end surface 11a of the peripheral wall portion 11, where the angle θ4 formed by the line segment connecting the end position EP2 and the midpoint S4 and the set movement route L1 is an obtuse angle. A plasticized region W2 is formed on the movement trajectory of the rotary tool F. The welded body 1 is formed by the above steps.

[0048] According to the manufacturing method of the joined body in this embodiment described above, in the removal section in which the rotary tool F is removed from the jacket body (first metal member) 2 having high hardness, the rotary tool F is removed while gradually decreasing its rotational speed compared to this section. This reduces the heat input to the jacket body 2, prevents cracking of the jacket body 2, and suppresses the generation of burrs. This improves the finish of the peripheral wall end surface 11a of the jacket body 2. In other words, it improves the finish of the surface of the joined body 1. Furthermore, by removing the rotary tool F while decreasing its rotational speed, friction between the jacket body 2 (first metal member) having high hardness and the rotary tool F can be reduced, preventing damage to the rotary tool F. Furthermore, according to this manufacturing method, it is possible to remove the rotary tool F from the jacket body (first metal member) 2 having high hardness, and a punching hole is formed on the first metal member side. Therefore, compared to when the rotary tool F is removed from the low-hardness sealing body (second metal member) 3, no punched holes are formed on the second metal member side, eliminating the need to repair the punched holes in the second metal member, and making it possible to install electronic components on the second metal member without performing pre-processing to repair the punched holes after friction stir welding. This increases the degree of freedom in designing a joined body formed by joining the first metal member and the second metal member by friction stir welding, and improves productivity.

[0049] Furthermore, the rotational speed of the rotating tool F may be set as appropriate, but if the rotational speed during friction stirring of the first butt joint J1 in this section is set to 100%, it is preferable to set the rotational speed during the separation section to 10% or more and 50% or less. Furthermore, assuming that the rotational speed in the separation section is gradually reduced from that in the main section, it is preferable to set the rotational speed when performing friction stirring of the first butt joint J1 in the main section to 5000 rpm or more and 20000 rpm or less, and to set the rotational speed in the separation section to 1000 rpm or more and 8000 rpm or less.

[0050] The rotation speed of the rotary tool F may be set as appropriate, but by setting it as described above, the above-mentioned effects can be more accurately achieved.

[0051] Furthermore, the frictional heat between the seal 3 and the stirring pin F2 stirs and plastically fluidizes the second aluminum alloy, primarily on the seal 3 side, at the first butt joint J1, thereby joining the step side 12b and the side 3c of the seal 3 at the first butt joint J1. Furthermore, by only slightly contacting the outer circumferential surface of the stirring pin F2 with the step side 12b of the jacket body 2, the intrusion of the first aluminum alloy from the jacket body 2 into the seal 3 can be minimized. As a result, the second aluminum alloy primarily on the seal 3 side is friction-stirred at the first butt joint J1, thereby suppressing a decrease in joint strength. In other words, in this joining process, the imbalance in material resistance experienced by the stirring pin F2 on one side and the other side of the rotation axis C of the stirring pin F2 can be minimized. As a result, the plastic flow material is friction-stirred in a balanced manner, thereby suppressing a decrease in joint strength. Furthermore, by increasing the plate thickness of the seal 3, metal shortage at the joint can be prevented.

[0052] In addition, in the pushing-in sections of the first and second main welding processes, the rotating tool F is moved from the starting positions SP1, SP2 to a position overlapping with the set movement route L1, and the stirring pin F2 is gradually pushed in until it reaches a predetermined depth, thereby preventing the rotating tool F from stopping on the set movement route L1 and causing excessive frictional heat. Similarly, in the removal section of the first main welding process and the second main welding process, the rotating tool F is moved from the set movement route L1 to the end positions EP1 and EP2, while the stirring pin F2 is gradually raised from a predetermined depth and removed, thereby preventing the rotating tool F from stopping on the set movement route L1 and causing excessive frictional heat.

[0053] These prevent excessive frictional heat on the set movement route L1 from being generated and causing an excessive amount of the first aluminum alloy to be mixed from the jacket body 2 into the sealing body 3, resulting in poor bonding.

[0054] Furthermore, by performing friction stir welding with the stirring pin F2 slightly in contact with both the step side surface 12b and the step bottom surface 12a, the first butt joint J1 and the second butt joint J2 can be reliably joined. Furthermore, by keeping the step side surface 12b and the stirring pin F2 in slight contact and the step bottom surface 12a and the stirring pin F2 in slight contact, it is possible to minimize the intrusion of the first aluminum alloy from the jacket body 2 into the sealing body 3.

[0055] Furthermore, in this welding process, the start positions SP1 and SP2 may be set as appropriate, but by setting the angles θ1 and θ3 between the start positions SP1 and SP2 and the set movement route L1 to be obtuse angles, the movement speed of the rotary tool F does not decrease at the intermediate points S1 and S3, and the rotary tool F smoothly transitions to this section. This makes it possible to prevent excessive frictional heat from occurring due to the rotary tool F stopping or decreasing its movement speed on the set movement route L1.

[0056] Furthermore, in this joining process, the positions of the end positions EP1 and EP2 may be set as appropriate, but by setting the angles θ2 and θ4 formed by the end positions EP1 and EP2 and the set movement route L1 to be obtuse angles, the movement speed of the rotary tool F does not decrease at the intermediate points S2 and S4, and the rotary tool F smoothly transitions to the departure section. This makes it possible to prevent excessive frictional heat from occurring due to the rotary tool F stopping or decreasing its movement speed on the set movement route L1.

[0057] Furthermore, in the main joining process of this embodiment, the rotation direction and travel direction of the rotary tool F may be set as appropriate, but the rotation direction and travel direction of the rotary tool F were set so that the jacket body 2 side was the shear side and the sealing body 3 side was the flow side of the plasticized region W1 formed in the movement trajectory of the rotary tool F. By setting the jacket body 2 side to be the shear side, the stirring action by the stirring pin F2 around the first butt joint J1 is enhanced, and a temperature rise in the first butt joint J1 can be expected, enabling a more reliable joining of the step side surface 12b and the side surface 3c of the sealing body 3 at the first butt joint J1.

[0058] The shear side (advancing side) refers to the side where the relative speed of the outer periphery of the rotary tool with respect to the parts to be welded is the sum of the magnitude of the tangential speed at the outer periphery of the rotary tool and the magnitude of the moving speed, while the flow side (retreating side) refers to the side where the relative speed of the rotary tool with respect to the parts to be welded becomes slower as the rotary tool rotates in the direction opposite to the moving direction of the rotary tool.

[0059] Furthermore, the first aluminum alloy of the jacket body 2 is made of a material having a higher hardness than the second aluminum alloy of the sealing body 3. This can improve the durability of the joined body 1. Preferably, the first aluminum alloy of the jacket body 2 is made of a cast aluminum alloy, and the second aluminum alloy of the sealing body 3 is made of a wrought aluminum alloy. By using an Al-Si-Cu-based aluminum alloy cast material such as JISH5302 ADC12 as the first aluminum alloy, the castability, strength, machinability, etc. of the jacket body 2 can be improved. Furthermore, by using a JIS A1000 series or A6000 series aluminum alloy as the second aluminum alloy, for example, the processability and thermal conductivity can be improved.

[0060] Furthermore, when the set movement route L1 for the main welding process is a closed route as in this embodiment, there is a problem that the rotary tool F and the clamp K1 interfere with each other during the main welding process, making the work complicated. However, according to this embodiment, the clamping position and the friction stir welding position are separated in the first main welding process and the second main welding process, so that the friction stir welding work can be performed efficiently.

[0061] In addition, in the main joining process, the entire circumference of the first butt joint J1 can be friction stir welded in the first main joining process and the second main joining process, thereby improving the airtightness and watertightness of the joined body. Furthermore, since the ends of the plasticized region W1 formed in the first main joining process and the plasticized region W2 formed in the second main joining process on the set movement route L1 overlap, the airtightness and watertightness can be more reliably improved.

[0062] Furthermore, by setting the inclination angle α of the stirring pin F2 and the inclination angle β of the step side surface 12b to be the same (parallel), the stirring pin F2 can be brought into uniform contact with the step side surface 12b over the entire height direction, thereby enabling well-balanced friction stir welding.

[0063] Furthermore, in this welding process, friction stirring is performed with the base end side of the stirring pin F2 of the rotary tool F exposed, so that the load acting on the friction stirring device can be reduced.

[0064] [2. First Modification] 12 and 13, the first modified example differs from the embodiment in the positions of start positions SP1 and SP2 in the main joining step. The first modified example will be described mainly focusing on the parts that differ from the embodiment.

[0065] In the first modified example, in the main joining process, start positions SP11 and SP12 are set on the set movement route L1 as shown in Figures 12 and 13. The midpoint S4 of the second main joining process is set on the set movement route L1 closer to the first region R1 (see Figure 3) than the start position SP11.

[0066] In the first modified example, in the first final welding process, friction stir welding is performed continuously in three sections: a push-in section from the start position SP11 to the midpoint S1, a main section from the midpoint S1 to the midpoint S2 on the set movement route L1, and a withdrawal section from the midpoint S2 to the end position EP1. A plasticized region W11 is formed in the movement trajectory of the rotary tool F. In addition, in the first modified example, friction stir welding is performed continuously in three sections: a push-in section from the start position SP12 to the midpoint S3, a main section from the midpoint S3 to the midpoint S4 on the set movement route L1, and a withdrawal section from the midpoint S4 to the end position EP2. In the main section of the second final welding process, the rotary tool F is moved from the midpoint S1 to the midpoint S4 so that the stirring pin F2 passes through the start position SP11. A plasticized region W12 is formed in the movement trajectory of the rotary tool F. In this way, in the main section of the second main welding step, the insertion hole formed at the start position SP11 can be filled with the plasticized region W12.

[0067] In the first modified example, in the push-in section of the first main welding step, the rotational speed of the rotary tool F when performing friction stir welding may be set appropriately, but the rotational speed of the rotary tool F in the push-in section may be gradually reduced from a rotational speed higher than the rotational speed of the rotary tool F in this section while the rotary tool is moved to the intermediate points S1, S3. In this case, it is preferable to change the rotational speed toward the rotational speed of the rotary tool F in this section so that the rotational speed becomes the rotational speed of the rotary tool F in this section when the stirring pin F2 reaches the intermediate points S2, S4.

[0068] According to this modification, the insertion hole provided at the start position SP11 on the set movement route L1 can be filled. Therefore, since no insertion hole remains in the jacket body (first metal member) 2 and the sealing body (second metal member) 3, repair of the insertion hole is unnecessary, and electronic components can be installed on the second metal member without performing pre-processing to repair the insertion hole after friction stir welding. Furthermore, compared to the embodiment, the plasticized region formed on the second metal member can be made smaller. Therefore, the degree of freedom in designing a joined body formed by friction stir welding of the first metal member and the second metal member can be increased, and productivity can be further improved.

[0069] [3. Second Modification] 14 and 15, the second modified example differs from the embodiment in the positions of start positions SP21 and SP22 in the main joining step. The second modified example will be described mainly focusing on the parts that differ from the embodiment.

[0070] 14 and 15, in the main joining process, start positions SP21, SP22 are set on the peripheral wall end surface 11a of the peripheral wall portion 11. The start positions SP21, SP22 are set at positions on the peripheral wall end surface 11a of the peripheral wall portion 11 that are outer than the set movement route L1. In the second modified example, the start positions SP21, SP22 are set at positions where the angles θ21, θ22 formed by the line segments connecting the start positions SP21, SP22 and the midpoints S1, S2 and the set movement route L1 are obtuse angles.

[0071] In the second modified example, in the first main welding process, friction stir welding is performed continuously in three sections: a push-in section from the start position SP21 to the midpoint S1, a main section from the midpoint S1 to the midpoint S2 on the set movement route L1, and a withdrawal section from the midpoint S2 to the end position EP1. A plasticized region W21 is formed in the movement trajectory of the rotary tool F. In addition, in the second modified example, friction stir welding is performed continuously in three sections: a push-in section from the start position SP22 to the midpoint S3, a main section from the midpoint S3 to the midpoint S4 on the set movement route L1, and a withdrawal section from the midpoint S4 to the end position EP2. A plasticized region W22 is formed in the movement trajectory of the rotary tool F.

[0072] In the second modified example, in the pushing-in section of the main welding process, the stirring pin F2 is gradually pushed in from the start positions SP21 and SP22 to reach a predetermined "predetermined depth" at least by the time it reaches the intermediate points S1 and S2. In other words, the rotating tool F is not allowed to remain in one place, but is gradually lowered while moving along the set movement route L1. The rotational speed of the rotating tool F in the pushing-in section may be gradually increased from a lower rotational speed than the rotational speed in this section as the rotating tool moves to the intermediate point S1. For example, if the rotational speed of the rotating tool F during friction stir welding of the first butt joint J1 in this section is 100%, the rotational speed in the pushing-in section can be set to 10% or more and 50% or less. The rotational speed in the pushing-in section relative to the rotational speed of the rotating tool F during friction stir welding of the first butt joint J1 is preferably 15% or more, more preferably 20% or more, and even more preferably 25% or more, and preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less. The rotation speed of the rotary tool F in the pushing section may be set appropriately, for example, to 1000 rpm or more and 8000 rpm or less. The rotation speed of the rotary tool F in the pushing section is preferably 2000 rpm or more, more preferably 3000 rpm or more, even more preferably 4000 rpm or more, and is preferably 7000 rpm or less, more preferably 6000 rpm or less, and even more preferably 5000 rpm or less.

[0073] According to this modification, the insertion hole can be formed on the jacket main body 2 (first metal member) side, and not on the sealing body (second metal member) 3 side. This eliminates the need to repair the insertion hole in the second metal member, and makes it possible to install electronic components on the second metal member without performing pre-processing to repair the insertion hole after friction stir welding. Furthermore, compared to the embodiment, the plasticized region formed on the sealing body 3 can be made smaller. Therefore, it is possible to further increase the degree of freedom in designing a joined body formed by friction stir welding of the first metal member and the second metal member, and to further improve productivity.

[0074] [4. Third Modification] In this embodiment, friction stir welding is performed while clamping in two separate steps, but it may be performed in one step, or may be performed while clamping in three or more separate steps. The third modified example differs from the embodiment in that the main joining process is performed in one step instead of two steps, as shown in Fig. 16. The third modified example will be described mainly focusing on the differences from the embodiment.

[0075] 16, in the main joining process of the third modified example, friction stir welding is performed continuously in three sections: a push-in section from the start position SP1 to the midpoint S1; a main section from the midpoint S1 on the set movement route L1 around the sealing body 3 to the midpoint S4; and a pull-out section from the midpoint S4 to the end position EP2. A plasticized region W31 is formed in the movement trajectory of the rotating tool F. In this case, friction stir welding is performed while clamping multiple locations on the jacket body 2 and the sealing body 3, and the clamps are temporarily released at the locations where the rotating tool F approaches, and then clamped again after the rotating tool F has passed through.

[0076] According to this modification, friction stir welding can be performed in a single process, thereby improving work efficiency.

[0077] [5. Fourth Modification] 17, the fourth modified example differs from the embodiment in that the position of the start position SP11 in the main joining process is different from that of the embodiment, and that the main joining process is performed in one go. The fourth modified example will be described mainly focusing on the differences from the embodiment.

[0078] In the fourth modified example, in the main joining process, a start position SP11 is set on a set movement route L1 as shown in Fig. 17. A midpoint S4 of the main joining process is set on the set movement route L1 closer to the first region R1 (see Fig. 3) than the start position SP11.

[0079] In the fourth modified example, as shown in FIG. 17 , the main welding process involves friction stir welding in three consecutive sections: a push-in section from the start position SP11 to the midpoint S1; a main section from the midpoint S1 on the set movement route L1 around the sealing body 3 to the midpoint S4; and a pull-out section from the midpoint S4 to the end position EP2. In the main section of the fourth main welding process, the rotary tool F is moved from the midpoint S1 to the midpoint S4 so that the stirring pin F2 passes through the start position SP11. A plasticized region W41 is formed along the movement path of the rotary tool F. As a result, in the main welding process of the fourth modified example, the insertion hole formed at the start position SP11 can be filled with the plasticized region W41. In this case, friction stir welding is performed while clamping multiple locations on the jacket body 2 and the sealing body 3. The clamps at the locations where the rotary tool F approaches are temporarily released and then clamped again after the rotary tool F has passed.

[0080] In the fourth modified example, in the push-in section of the main welding step, the rotational speed of the rotary tool F when performing friction stir welding may be set appropriately, but the rotational speed of the rotary tool F in the push-in section may be gradually reduced from a rotational speed higher than the rotational speed of the rotary tool F in this section as the rotary tool F moves to the midpoint S1. In this case, it is preferable to change the rotational speed toward the rotational speed of the rotary tool F in this section so that the rotational speed becomes the rotational speed of the rotary tool F in this section when the stirring pin F2 reaches the midpoint S1.

[0081] According to this modification, friction stir welding can be performed in a single process, thereby improving work efficiency. Furthermore, according to this modification, the insertion hole provided at the start position SP11 on the set movement route L1 can be filled. Therefore, since the insertion hole does not remain on the sealing body (second metal member) 3 side, repairing the insertion hole in the second metal member is unnecessary, and electronic components can be installed on the second metal member without performing pre-processing to repair the insertion hole after friction stir welding. Furthermore, compared to the embodiment, the plasticized region formed on the sealing body 3 can be made smaller. Therefore, the degree of freedom in designing a joined body formed by friction stir welding of a first metal member and a second metal member can be increased, and productivity can be further improved.

[0082] Furthermore, in this modification, before the rotating tool F is released from the jacket body (first metal member) 2 at the end position EP2, the rotating tool F is moved so that the stirring pin F2 passes through the start position SP11. As a result, in this modification, when performing friction stir welding along the set movement route L1, the only insertion hole provided at the start position SP11 can be filled. Therefore, no insertion holes remain on the set movement route L1, which further increases the degree of freedom in design and further improves productivity.

[0083] [6. Other] Although the embodiments and modifications of the present invention have been described above, appropriate design changes are possible within the scope of the present invention. For example, at the start positions SP1 and SP2, the rotary tool F is gradually pushed in while being moved, but it may be pushed to a predetermined position at the start positions SP1 and SP2 and then moved. Also, at the end positions EP1 and EP2, the rotary tool F is gradually raised (removed) while being moved, but it may be moved to a predetermined depth (constant depth) to the end positions EP1 and EP2, and then the rotary tool F may be raised vertically at the end positions EP1 and EP2 and removed.

[0084] Furthermore, before the main joining process, a temporary joining process may be performed to temporarily join the jacket body 2 and the sealing body 3. This prevents gaps between the jacket body 2 and the sealing body 3 during the main joining process. The temporary joining process may be performed by friction stirring using a temporary joining rotary tool, or by welding. Furthermore, in the loading section and the removal section, the movement route may be set so that the movement trajectory of the rotary tool F forms a curve (for example, an arc) in plan view. This allows for smooth transition from the loading section to the main section, or from the main section to the removal section.

[0085] Furthermore, in the present embodiment, a case has been described in which friction stir welding is performed using the rotary tool F by inserting only the stirring pin F2 into the jacket main body 2 and the sealing body 3. The rotary tool and the friction stir welding are not limited to this, and for example, a rotary tool including a shoulder and a stirring pin hanging down from the shoulder may be used, with the stirring pin inserted into the jacket main body 2 and the sealing body 3 and the shoulder in contact with the peripheral wall portion 11 of the jacket main body 2 and the surface 3a of the sealing body 3, and friction stir welding may be performed. [Explanation of symbols]

[0086] 1 zygote 2 Jacket body (first metal member) 3 Sealing body (second metal member) F Rotate Tool F2 Stirring pin F3 flat surface J1 First joint J2 Second joint EP1 end position EP2 end position W plasticization region

Claims

1. A method for manufacturing a joined body by friction stir joining a first metal member and a second metal member, comprising: the first metal member is formed of a first aluminum alloy, the second metal member is formed of a second aluminum alloy, and the first aluminum alloy is a material type having a higher hardness than the second aluminum alloy; The rotary tool used in friction stirring has a stirring pin, a butting step of butting a side surface of the first metal member against a side surface of the second metal member to form a butted portion; a main joining process of inserting the stirring pin of the rotating rotary tool into the second metal member, and friction stir welding the butted portions to a predetermined depth along a set movement route set inside a side surface of the second metal member while keeping the outer circumferential surface of the stirring pin in slight contact with the first metal member, In the main welding process, an end position is set on the first metal member outside the set movement route, and after friction stir welding of the butt joint portion, the rotary tool is moved to the end position while a separation section is included in which the rotary tool is separated from the first metal member at the end position, In the main welding step, the stirring pin is rotated at a predetermined rotational speed to perform friction stir welding of the butted portions, In the removal section, the rotation tool is moved toward the end position while the rotation speed is gradually reduced from the predetermined rotation speed, thereby removing the rotation tool from the first metal member. A method for producing a bonded body, comprising:

2. In the main joining process, when the rotational speed during friction stir welding of the butt joint portion is 100%, the final rotational speed in the separation section is 10% or more and 50% or less. The method for producing the bonded body according to claim 1 .

3. In the main joining step, the rotation speed when performing friction stir welding of the butted portions is 5000 rpm or more and 20000 rpm or less, The final rotation speed in the separation section is 1000 rpm or more and 8000 rpm or less. The method for producing the bonded body according to claim 1 or 2.

4. Further comprising a preparation step of forming the first metal member by die casting. The method for producing the bonded body according to any one of claims 1 to 3.

5. In the main welding process, a start position is set on the set movement route, and before friction stir welding of the butt joint portion, the stirring pin is inserted into the start position and the rotary tool is moved and lowered from the start position in a push-in section, 5. The method for manufacturing a joined body according to claim 1, wherein, in the main joining step, before the rotary tool is detached from the first metal member at the end position, the rotary tool is moved so that the stirring pin passes through the start position to perform friction stir welding.

6. In the main welding process, a start position is set on the set movement route, and before friction stir welding of the butt joint portion, the stirring pin is inserted into the start position and the rotary tool is moved and lowered from the start position in a push-in section, In the putting-in section, the rotational tool is moved and lowered toward an intermediate point set on the set movement route while gradually decreasing the rotational speed from a rotational speed higher than the predetermined rotational speed. The method for producing the bonded body according to any one of claims 1 to 5.

7. In the main welding process, a start position is set on the second metal member that is inside the set movement route, and before friction stir welding of the butt portion, the stirring pin is inserted into the start position, and the rotary tool is moved and lowered from the start position in a push-in section. In the pushing-in section, the rotation tool is lowered while being moved while gradually decreasing the rotation speed from a rotation speed higher than the predetermined rotation speed. The method for producing the bonded body according to any one of claims 1 to 4.

8. In the main welding process, a start position is set on the first metal member outside the set movement route, and before friction stir welding of the butt joint portion, the stirring pin is inserted into the start position and the rotary tool is moved and lowered from the start position in a push-in section, In the pushing-in section, the rotation tool is moved and lowered while gradually increasing the rotation speed from a rotation speed lower than the predetermined rotation speed. The method for producing the bonded body according to any one of claims 1 to 4.

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