JP7322748B2 - Composite structure manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a composite structure.

Patent Literature 1 discloses a method for manufacturing a composite slab (composite structure). In the manufacturing method of the composite structure, the composite structure is formed by arranging the second metal member in the concave portion of the box-shaped first metal member and friction stir welding them.

JP 2019-214193 A

A relatively thin composite structure may be formed using a first metal member having a thickness of several millimeters. In such a case, it is preferable to form the box-shaped first metal member by press-molding a metal plate in consideration of formability. However, press molding causes springback, which makes it difficult to form the first metal member, and thus the composite structure, into a desired shape.

For example, when it is desired to make the angle formed by the bottom portion of the first metal member constituting the composite structure and the peripheral wall portion a right angle, the peripheral wall portion tilts outward due to springback after press molding. In addition, the peripheral wall may tilt outward due to softening due to frictional heat during friction stir welding or the pressing force of the rotating tool. In particular, in the case of press molding, the corners of the bottom and the peripheral wall are strictly rounded, so the corners of the back surface of the bottom of the first metal member and the outer peripheral surface of the peripheral wall are made to be perpendicular to each other. is extremely difficult.

Further, for example, when it is desired to form an acute angle between the bottom portion and the peripheral wall portion of the first metal member that constitutes the composite structure, the first metal member cannot be formed by press molding due to die cutting. This makes it difficult to form a composite structure in which the angle between the bottom portion of the first metal member and the peripheral wall portion is an acute angle (undercut).

From this point of view, the present invention aims to provide a method of manufacturing a composite structure that can easily form a right angle or an acute angle between the bottom portion of the first metal member and the peripheral wall portion that constitute the composite structure. Make it an issue.

In order to solve such problems, the present invention provides a method for manufacturing a composite structure by performing friction stir, wherein a bottom portion and a frame-shaped peripheral wall portion rising from the peripheral edge portion of the bottom portion are provided. A first metal member having a concave portion and a flange portion protruding outward from an end portion of the peripheral wall portion, and a second metal member arranged in the concave portion of the first metal member are prepared. a preparation step, placing the second metal member in the concave portion of the first metal member, and abutting the inner peripheral surface of the peripheral wall portion of the first metal member against the outer peripheral surface of the second metal member to form the first A placing step of forming a butt portion, a first butt portion joining step of performing friction stir welding of the first butt portion using a rotating rotating tool, and inserting the rotating rotating tool from the surface of the second metal member. Friction molding in which the rotating tool is relatively moved along the first abutting portion while pressing the peripheral wall portion of the first metal member against the molding surface of the mold arranged on the back side of the first metal member. and, in the friction molding step, the angle formed by the bottom surface of the molding surface of the mold and the inner peripheral surface of the mold is formed at a right angle or an acute angle.

According to this manufacturing method, the first metal member constituting the composite structure is formed by performing a friction molding step in which the peripheral wall portion of the first metal member is pressed against the molding surface of the mold having a right angle or an acute angle to form the shape. The angle formed by the bottom portion of the member and the peripheral wall portion can be easily made a right angle or an acute angle. In addition, since the first metal member and the second metal member are softened by the frictional heat of friction stirring, they can be easily shaped.

Further, in the friction molding step, it is preferable that the outer peripheral surface of the stirring pin of the rotating tool is parallel to the inner peripheral surface of the molding surface.

According to this manufacturing method, the peripheral wall portion can be uniformly pressed against the inner peripheral surface of the molding surface in the height direction, so that the shape can be formed more accurately.

Further, in the preparation step, the hardness of the first metal member is set higher than that of the second metal member, and in the first butt portion joining step, a rotating tool that rotates from the surface of the second metal member is used. It is preferable to perform friction stir while inserting the rotating tool and slightly contacting the stirring pin of the rotating tool with the first metal member.

According to this manufacturing method, the first abutting portion can be joined mainly by friction stir between the second metal member and the rotating tool. This makes it difficult for the metal of the first metal member, which has a high hardness, to mix with the second metal member, thereby preventing defective joining caused by friction stir between metals of different types.

In addition, in the placing step, the surface of the bottom portion of the first metal member and the back surface of the second metal member are overlapped to form an overlapping portion, and before performing the first butt portion joining step, the A rotary tool that rotates is inserted from the surface of the second metal member, and only the stirring pin of the rotary tool is brought into contact with the second metal member or the first metal member and the second metal member, and friction stir is performed. It is preferable to include a step of joining the overlapping portions by joining the overlapping portions.

According to this manufacturing method, the strength of the composite structure can be increased because the overlapped portion can be joined. In addition, it is possible to prevent positional deviation between the first metal member and the second metal member in the step of joining the first butt portion.

In addition, in the overlapping portion joining step, a rotating tool is inserted into the central portion of the surface of the second metal member, and relatively moved outward from the central portion so as to draw a continuous spiral trajectory in a plan view. It is preferable to friction stir the entirety of the polymerization portion.

According to this manufacturing method, the entire overlapped portion can be easily joined. Further, by spirally moving the rotary tool outward from the central portion, it is possible to prevent wrinkles from occurring in the first metal member and the second metal member.

Moreover, it is preferable that the overlapped portion joining step and the first butt portion joining step are continuously performed using one rotary tool.

According to this manufacturing method, since it is not necessary to replace the rotary tool for each process, the joining cycle can be shortened.

In addition, in the first butt portion joining step, a proximal side pin and a distal side pin are provided, the taper angle of the proximal side pin is set larger than the taper angle of the distal side pin, and the proximal side pin It is preferable to use a rotating tool having a stepped portion formed on the outer peripheral surface of the base end side pin, and perform friction stir while the outer peripheral surface of the proximal pin is in contact with the surface of the second metal member.

According to this manufacturing method, since the plastic flow material can be pressed by the outer peripheral surface of the base end pin in the step of joining the first butt portion, it is possible to suppress the occurrence of burrs.

In addition, in the first butt portion joining step, a rotary tool having a shoulder portion and an agitating pin hanging down from the bottom surface of the shoulder portion is used to bring the bottom surface of the shoulder portion into contact with the surface of the second metal member. Friction stirring is preferably performed in this state.

According to this manufacturing method, since the plastic flow material can be pressed by the bottom surface of the shoulder portion in the step of joining the first butt portion, it is possible to suppress the occurrence of burrs.

Further, in the placing step, when the second metal member is placed on the first metal member, whether the surface of the second metal member is the same as the surface of the flange portion of the first metal member, Alternatively, it is preferable to set the thickness of the second metal member so as to be higher than the surface of the flange portion.

According to this manufacturing method, it is possible to prevent metal shortage in the joint portion of the first butt portion.

Moreover, it is preferable that the step of joining the first butt portion and the step of friction molding be performed simultaneously with one rotary tool.

According to this manufacturing method, each step can be performed simultaneously, so that the bonding cycle can be shortened. In addition, since there is no need to replace the rotary tool for each process, the joining cycle can be shortened.

According to the method for manufacturing a composite structure according to the present invention, the angle formed by the bottom portion of the first metal member and the peripheral wall portion can be easily made a right angle or an acute angle.

It is a side view which shows the 1st rotation tool which concerns on embodiment of this invention. It is an enlarged cross-sectional view of the first rotary tool. It is a sectional view showing the first modification of the first rotating tool. It is a cross-sectional view showing a second modification of the first rotating tool. It is a cross-sectional view showing a third modification of the first rotating tool. 1 is a perspective view showing a composite structure according to a first embodiment of the invention; FIG. 1 is a cross-sectional view showing a composite structure according to a first embodiment; FIG. FIG. 4A is a cross-sectional view showing a preparation step and a placement step of the manufacturing method of the composite structure according to the first embodiment; FIG. 4 is a plan view showing a step of joining overlapping portions in the method for manufacturing a composite structure according to the first embodiment; FIG. 4 is a cross-sectional view showing a step of joining overlapping portions in the method for manufacturing a composite structure according to the first embodiment; FIG. 4 is a plan view showing a first butt joint joining step in the method for manufacturing a composite structure according to the first embodiment; FIG. 4 is a cross-sectional view showing a first butt joint joining step in the method for manufacturing a composite structure according to the first embodiment; FIG. 4 is a plan view showing a friction molding step in the method for manufacturing a composite structure according to the first embodiment; FIG. 4 is a cross-sectional view showing a friction molding step in the method for manufacturing a composite structure according to the first embodiment; FIG. 4A is a cross-sectional view showing a preparation step and a placement step of a method for manufacturing a composite structure according to a second embodiment of the present invention; FIG. 10 is a plan view showing a step of joining overlapping portions in the method for manufacturing a composite structure according to the second embodiment; FIG. 10 is a cross-sectional view showing a step of joining overlapping portions in a method for manufacturing a composite structure according to a second embodiment; FIG. 11 is a plan view showing a first butt joint joining step in the method for manufacturing a composite structure according to the second embodiment; FIG. 10 is a cross-sectional view showing a first butt joint joining step in the method for manufacturing a composite structure according to the second embodiment; FIG. 10 is a plan view showing a friction molding step in the method for manufacturing a composite structure according to the second embodiment; FIG. 10 is a cross-sectional view showing a friction molding step of the method for manufacturing a composite structure according to the second embodiment; 10A and 10B are cross-sectional views showing a preparation step and a placing step of a method for manufacturing a composite structure according to Modification 1; FIG. 10 is a cross-sectional view showing a step of joining overlapping portions in a method for manufacturing a composite structure according to Modification 1; FIG. 10 is a cross-sectional view showing a first butt joint joining step in the method for manufacturing a composite structure according to Modification 1; FIG. 10 is a cross-sectional view showing a friction molding step of a method for manufacturing a composite structure according to Modification 2; FIG. 10 is a cross-sectional view showing the method for manufacturing a composite structure according to Modification 2 after the friction molding step; FIG. 4 is a cross-sectional view showing a composite structure according to a third embodiment of the invention; FIG. 10 is a cross-sectional view showing a preparation step and a placement step of the manufacturing method of the composite structure according to the third embodiment; FIG. 10 is a cross-sectional view showing a step of joining overlapping portions in a method for manufacturing a composite structure according to the third embodiment; FIG. 11 is a cross-sectional view showing a first butt joint joining step in the method for manufacturing a composite structure according to the third embodiment; FIG. 10 is a cross-sectional view showing a friction molding step of the method for manufacturing a composite structure according to the third embodiment; FIG. 10 is a cross-sectional view showing a preparation step and a placement step of a method for manufacturing a composite structure according to a fourth embodiment of the present invention; FIG. 11 is a cross-sectional view showing a step of joining overlapping portions in a method for manufacturing a composite structure according to a fourth embodiment; FIG. 10 is a cross-sectional view showing a first butt joint joining step in the method for manufacturing a composite structure according to the fourth embodiment; FIG. 11 is a cross-sectional view showing a friction molding step of a method for manufacturing a composite structure according to the fourth embodiment;

Embodiments of the present invention will be described with reference to the drawings as appropriate. The present invention is not limited only to the following embodiments and modifications. In addition, each component in the embodiment and modifications can be appropriately combined in whole or in part with other embodiments and modifications.

First, the first rotating tool used in the method for manufacturing a composite structure according to this embodiment will be described. As shown in FIG. 1, the first rotating tool F is made of tool steel, for example, and includes a base shaft portion F1, a proximal pin F2, and a distal pin F3. The proximal pin F2 and the distal pin F3 constitute a "stirring pin". The base shaft portion F1 has a cylindrical shape and is a portion connected to the main shaft of the friction stirrer.

The base end pin F2 is continuous with the base shaft portion F1 and tapers toward the tip. The proximal pin F2 has a truncated cone shape. The taper angle A of the proximal pin F2 may be set appropriately, and is, for example, 135 to 160°. If the taper angle A is less than 135° or exceeds 160°, the joint surface roughness after friction stir increases. The taper angle A is larger than the taper angle B of the distal pin F3, which will be described later. As shown in FIG. 2, a stepped pin stepped portion F21 is formed over the entire height direction on the outer peripheral surface F5 of the proximal pin F2. The pin stepped portion F21 is spirally formed clockwise or counterclockwise. That is, the pin stepped portion F21 has a spiral shape when viewed from above, and has a stepped shape when viewed from the side. For example, when rotating the first rotary tool F to the right, the pin stepped portion F21 is set to rotate counterclockwise from the base end side toward the tip end side.

In addition, when rotating the first rotating tool F to the left, it is preferable to set the pin stepped portion F21 clockwise from the proximal side to the distal side. As a result, the plastic flow material is guided to the tip end side by the pin stepped portion F21, so that the amount of metal overflowing to the outside of the metal members to be joined can be reduced. The pin step portion F21 is composed of a step bottom surface F21a and a step side surface F21b. The distance X1 (horizontal distance) between the vertices F21c, F21c of the adjacent pin stepped portions F21 is appropriately set according to the step angle C and the height Y1 of the step side face F21b, which will be described later.

The height Y1 of the stepped side surface F21b may be set as appropriate, and is set to 0.1 to 0.4 mm, for example. If the height Y1 is less than 0.1 mm, the joint surface roughness becomes large. On the other hand, when the height Y1 exceeds 0.4 mm, the joint surface roughness tends to increase, and the number of effective stepped portions (the number of pin stepped portions F21 in contact with the metal members to be joined) also decreases.

The step angle C between the step bottom surface F21a and the step side surface F21b may be set appropriately, but is set to 85 to 120°, for example. The stepped bottom surface F21a is parallel to the horizontal plane in this embodiment. The stepped bottom surface F21a may be inclined in the range of −5° to 15° with respect to the horizontal plane toward the outer peripheral direction from the rotation axis of the tool (minus is downward with respect to the horizontal plane, plus is with respect to the horizontal plane above). The distance X1, the height Y1 of the stepped side surface F21b, the stepped angle C, and the angle of the stepped bottom surface F21a with respect to the horizontal plane are set so that the plastic flow material does not stay inside the pin stepped portion F21 and adhere to the outside when performing friction stir. In addition, the step bottom F21a presses the plastic flow material to reduce the joint surface roughness.

As shown in FIG. 1, the distal pin F3 is formed continuously with the proximal pin F2. The distal pin F3 has a truncated cone shape. The tip of the tip side pin F3 is a tip face F4 perpendicular to the rotation axis. A taper angle B of the distal pin F3 is smaller than a taper angle A of the proximal pin F2. As shown in FIG. 2, a spiral groove F31 is engraved on the outer peripheral surface F6 of the distal pin F3. The spiral groove F31 may be either clockwise or counterclockwise, but when the first rotating tool F is rotated clockwise, it is set counterclockwise from the proximal side to the distal side.

In addition, when rotating the first rotating tool F counterclockwise, it is preferable to set the spiral groove F31 clockwise from the proximal side to the distal side. As a result, the plastic flow material is guided to the tip side by the spiral groove F31, so that the amount of metal overflowing to the outside of the metal members to be joined can be reduced. The spiral groove F31 is composed of a spiral bottom surface F31a and a spiral side surface F31b. The distance (horizontal distance) between the apexes F31c, F31c of the adjacent spiral grooves F31 is defined as length X2. Let the height of the spiral side surface F31b be a height Y2. A spiral angle D formed by the spiral bottom surface F31a and the spiral side surface F31b is, for example, 45 to 90°. The spiral groove F31 has the role of increasing the frictional heat by coming into contact with the metal members to be joined and guiding the plastic flow material to the tip side. Also, the first rotary tool F may be attached to a robot arm having a rotary drive means such as a spindle unit at its tip.

The design of the first rotary tool F can be changed as appropriate. FIG. 3 is a side view showing a first modified example of the first rotating tool of the present invention. As shown in FIG. 3, in the first rotary tool FA according to the first modification, the step angle C between the step bottom surface F21a and the step side surface F21b of the pin step portion F21 is 85°. The stepped bottom surface F21a is parallel to the horizontal plane. In this way, the stepped bottom surface F21a is parallel to the horizontal surface, and the stepped angle C may be an acute angle within a range in which the plastic flow material stays and adheres to the pin stepped portion F21 during friction stirring and escapes to the outside. .

FIG. 4 is a side view showing a second modification of the first rotating tool of the present invention; As shown in FIG. 4, in the first rotary tool FB according to the second modification, the step angle C of the pin step portion F21 is 115°. The stepped bottom surface F21a is parallel to the horizontal plane. In this manner, the stepped bottom surface F21a may be parallel to the horizontal plane, and the stepped angle C may be an obtuse angle within the range of functioning as the pin stepped portion F21.

FIG. 5 is a side view showing a third modification of the first rotary tool of the present invention; As shown in FIG. 5, in the first rotating tool FC according to the third modification, the stepped bottom surface F21a is inclined upward by 10° with respect to the horizontal plane from the rotating shaft of the tool toward the outer peripheral direction. The stepped side surface F21b is parallel to the vertical plane. In this manner, the stepped bottom surface F21a may be formed so as to be inclined upward from the horizontal surface toward the outer peripheral direction from the rotating shaft of the tool within a range where the plastic flow material can be pressed during friction stirring. The first to third modified examples of the first rotating tool described above can also produce effects equivalent to those of the following embodiments.

In this embodiment, the first rotating tool F is attached to a friction stirrer that can move horizontally and vertically. Note that the first rotating tool F may be attached to a robot arm having a rotation drive means such as a spindle unit at its tip.

[First embodiment]
A composite structure and a method for manufacturing a composite structure according to embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 6, in the method for manufacturing a composite structure according to the embodiment of the present invention, a composite structure 1 is manufactured by joining a first metal member 2 and a second metal member 3 by friction stir welding. be. In addition, the "front surface" in the following description means the surface on the opposite side of the "back surface".

The first metal member 2 has a box shape including a bottom portion 10, a peripheral wall portion 11, and a flange portion 12, as shown in FIGS. The plate thickness of the first metal member 2 is generally constant, and is about several millimeters in this embodiment. The bottom portion 10 is a plate-like portion that is rectangular in plan view. The peripheral wall portion 11 is a rectangular frame-shaped wall rising from the peripheral portion of the bottom portion 10 . The flange portion 12 protrudes outward from the distal end portion of the peripheral wall portion 11 . A concave portion 13 is formed by the bottom portion 10 and the peripheral wall portion 11 . The angle formed by the bottom portion 10 and the peripheral wall portion 11 is vertical. More specifically, the angle formed by the back surface 10b of the bottom portion 10 and the outer peripheral surface 11b of the peripheral wall portion 11 is also perpendicular.

The second metal member 3 is a plate-like member arranged in the recess 13 of the first metal member 2 . The second metal member 3 has substantially the same shape as the concave portion 13 . The surface 3a of the second metal member 3 and the surface 12a of the flange portion 12 are flush with each other. A first butted portion J1 where the inner peripheral surface 11a of the peripheral wall portion 11 and the outer peripheral surface 3c of the second metal member 3 are butted against each other is joined by friction stir to form a plasticized region W2. The plasticized region W2 is formed over the entire circumferential direction along the first butted portion J1.

A superimposed portion J2 where the surface 10a of the bottom portion 10 and the back surface 3b of the second metal member 3 are superimposed is joined by friction welding to form a plasticized region W1. The plasticized region W1 is formed over the entire overlapping portion J2. The plasticized region W3 is a plasticized region formed by a friction molding process, which will be described later.

Although the first metal member 2 and the second metal member 3 may be made of the same kind of metal, they are made of different materials in this embodiment. The first metal member 2 and the second metal member 3 may have the same hardness. ing. For example, in this embodiment, the first metal member 2 is made of an Al--Mg alloy (A5052 or the like). Further, for example, in this embodiment, the second metal member 3 is made of Al (A1050 or the like). In this specification, hardness refers to Brinell hardness, which can be measured by a method according to JIS Z 2243.

Next, a method for manufacturing a composite structure according to this embodiment will be described. In the method for manufacturing a composite structure, a preparation step, a placing step, a overlapping portion joining step, a first butt portion joining step, and a friction molding step are performed.

The preparation step is a step of preparing the first metal member 2 and the second metal member 3 . The first metal member 2 is formed by press-molding a plate-shaped material. The second metal member 3 is formed by extrusion molding, for example. As shown in FIG. 8, the first metal member 2 is press-formed so that the bottom portion 10 and the peripheral wall portion 11 are substantially perpendicular to each other, but the corner portions are rounded and bent.

The placing step is a step of placing the second metal member 3 on the first metal member 2, as shown in FIG. In the placing step, first, the second metal member 3 is placed on the mold 30 . The molding die 30 has a concave molding surface 31 composed of a bottom surface 31a and an inner peripheral surface 31b. The inner peripheral surface 31b is perpendicular to the bottom surface 31a. That is, the molding surface 31 of the molding die 30 is formed to be a rectangular parallelepiped hollow portion. A plurality of clamps 40 are provided on the surface of the mold 30 . The clamp 40 is a member that presses the flange portion 12 and restrains the first metal member 2 to the mold 30 so that it cannot move.

In the placing step, after fixing the first metal member 2 to the mold 30 , the second metal member 3 is fitted into the concave portion 13 of the first metal member 2 and placed. In the mounting step, the inner peripheral surface 11a of the peripheral wall portion 11 and the outer peripheral surface 3c of the second metal member 3 are brought into contact with each other to form the first butting portion J1. Further, the surface 10a of the bottom portion 10 and the back surface 3b of the second metal member 3 are overlapped to form an overlapped portion J2. A gap P is formed between the corner of the mold 30 and the corner of the second metal member 3 . The surface 3a of the second metal member 3 and the surface 12a of the flange portion 12 are flush with each other. The same mold 30 may be used in the press molding process and the placement process. As a result, work can be saved.

As shown in FIGS. 9 and 10, the overlapped portion joining step is a step of joining the overlapped portion J2 by friction stir welding. As shown in FIG. 10, a second rotary tool G is used in the overlapping portion joining step. The second rotating tool G is made of tool steel and has a connecting portion G1 and an agitating pin G2. The connecting portion G1 is a portion attached to the rotating shaft of the friction stirrer. The stirring pin G2 is coaxially suspended from the connecting portion G1 and is tapered. The tip surface G3 of the stirring pin G2 is flat and perpendicular to the rotation center axis Z. As shown in FIG. A spiral groove is formed on the outer peripheral surface G4 of the stirring pin G2. For example, when rotating the second rotating tool G to the right, the helical groove is set counterclockwise from the proximal side to the distal side.

In addition, when rotating the second rotating tool G to the left, it is preferable to set the spiral groove clockwise from the proximal side to the distal side. As a result, the plastic flow material is guided to the tip end side by the stirring pin G2, so that the amount of metal overflowing to the outside of the metal members to be joined (the first metal member 2 and the second metal member 3) can be reduced.

In the overlapped portion joining step, as shown in FIG. 9, the stirring pin G2 of the second rotary tool G that rotates to the right is set perpendicular to the surface 3a, and the start position is set at the center of the surface 3a of the second metal member 3. Insert into SP1. Then, the second rotating tool G is relatively displaced continuously from the central portion toward the outer side to friction stir weld the overlapped portion J2. A plasticized region W1 is formed in the locus of movement of the second rotating tool G. As shown in FIG. In the overlapped portion joining step, the second rotating tool G is relatively moved so as to form a helical movement trajectory from the central portion toward the outside while overlapping the ends of the plasticized regions W1 in the width direction.

As shown in FIG. 10 , in the overlapped portion joining step, the insertion depth is set so that the tip surface G3 of the stirring pin G2 slightly contacts the bottom portion 10 of the first metal member 2 . Also, in the overlapped portion joining step, only the stirring pin G2 is brought into contact with the first metal member 2 and the second metal member 3. As shown in FIG. In other words, friction stir is performed with the base end side of the stirring pin G2 exposed. The overlapping portion joining step may be performed by bringing the stirring pin G2 into contact only with the second metal member 3 . In this case, the frictional heat between the stirring pin G2 and the second metal member 3 causes plastic flow and the overlapped portion J2 is joined.

In the overlapped portion joining step, as shown in FIG. 10 , it is preferable that the peripheral wall portion 11 and the second rotating tool G do not come into contact with each other at the outer peripheral edge of the second metal member 3 . As a result, it is possible to prevent the metal of the first metal member 2 from being mixed into the second metal member 3 in the overlapping portion joining step. When reaching the end position EP<b>1 set at the corner of the second metal member 3 , the second rotating tool G is separated from the second metal member 3 .

In the present embodiment, the overlapping portion joining step was performed with the second rotating tool G, but the first rotating tool F, the third rotating tool H or the fourth rotating tool K described later, or other rotating tools good too. In addition, in the overlapped portion joining step, the route of the rotary tool may be set so as to follow another movement trajectory.

As shown in FIGS. 11 and 12, the first butt portion joining step is a step of friction stir welding the first butt portion J1. A first rotary tool F is used in the first butt portion joining step. In the first butt joint joining step, the tip side pin F3 is inserted perpendicularly to the surface 3a of the second metal member 3 at the start position SP2 set in the vicinity of the first butt J1. Then, the first rotating tool F is relatively moved along the first butted portion J1, and the first butted portion J1 is friction stir welded.

As shown in FIG. 12, in the first butt portion joining step, the base end pin F2 is brought into slight contact with the first metal member 2 to perform friction stir welding. In the first butt portion welding step, the friction stir welding is performed while the outer peripheral surface F5 of the base end pin F2 of the first rotating tool F is in contact with the surface 3a of the second metal member 3 and the surface 12a of the flange portion 12. I do. A plasticized region W2 is formed in the movement trajectory of the first rotating tool F. As shown in FIG. The first rotating tool F is made to go around along the first abutting portion J1 to overlap the plasticized region W2, and then the first rotating tool F is separated from the surface 3a of the second metal member 3 at the end position EP2. In the present embodiment, the first butt joint joining step was performed with the first rotating tool F, but the second rotating tool G, the third rotating tool H or the fourth rotating tool K described later, or other rotating tools were used. may

The friction molding step is a step of shaping the first metal member 2 by pressing the first metal member 2 against the mold 30 using the third rotating tool H, as shown in FIGS. The third rotating tool H is made of tool steel and has a connecting portion H1 and a stirring pin H2.

The connecting portion H1 is a portion attached to the rotating shaft of the friction stirrer. The stirring pin H2 is coaxially suspended from the connecting portion H1 and has a columnar shape. That is, the outer diameter of the stirring pin H2 is constant. The tip surface H3 of the stirring pin H2 is flat and perpendicular to the rotation center axis Z. As shown in FIG. A spiral groove is formed on the outer peripheral surface H4 of the stirring pin H2. For example, when rotating the third rotating tool H to the right, the spiral groove is set counterclockwise from the proximal side to the distal side.

In addition, when rotating the third rotating tool H to the left, it is preferable to set the spiral groove clockwise from the proximal side to the distal side. As a result, the plastic flow material is guided to the tip side by the stirring pin H2, so that the amount of metal overflowing to the outside of the second metal member 3 can be reduced.

In the friction molding step, the stirring pin H2 is inserted perpendicularly to the surface 3a of the second metal member 3 at a start position SP3 set near the first butting portion J1 on the surface 3a. Then, the third rotary tool H is relatively moved along the first butted portion J1.

As shown in FIG. 14, in the friction molding step, friction stir is performed with the stirring pin H2 of the third rotating tool H slightly separated from the bottom portion 10 and the peripheral wall portion 11, and the stirring pin H2 and the friction-stirred plastic The first metal member 2 is shaped by pressing the bottom portion 10 and the peripheral wall portion 11 against the bottom surface 31a and the inner peripheral surface 31b of the molding surface 31 with the fluid material. The outer peripheral surface H4 of the stirring pin H2 and the inner peripheral surface 31b of the molding surface 31 are parallel or substantially parallel. Further, the tip surface H3 of the stirring pin H2 and the bottom surface 31a of the molding surface 31 are parallel or substantially parallel. In the friction molding process, it is preferable to press the first metal member 2 against the molding surface 31 so that the gap P (see FIG. 12) is eliminated. A plasticized region W3 is formed in the movement trajectory of the third rotating tool H. As shown in FIG. The third rotating tool H is made to go around along the first abutting portion J1, and when the plasticized region W3 is overlapped, the third rotating tool H is separated from the surface 3a of the second metal member 3 at the end position EP3. The composite structure 1 (see FIG. 6) is formed by the above steps.

In this embodiment, the friction molding process is performed with the third rotating tool H, but the first rotating tool F, the second rotating tool G, the fourth rotating tool K described later, or other rotating tools may be used. .
At this time, the central axis of rotation of each rotating tool may be appropriately inclined so that the stirring pin of each rotating tool and the inner peripheral surface of the forming surface are parallel to each other. Moreover, in the friction molding process, it is preferable that the stirring pin of the rotary tool and the peripheral wall portion 11 are separated from each other, but they may be brought into contact with each other if only slightly.

According to the method for manufacturing a composite structure according to the present embodiment, the bottom portion 10 and the peripheral wall portion 11 of the first metal member 2 are formed on the molding surface 31 (the bottom surface 31a and the inner peripheral surface 31b) of the mold 30 forming a right angle. By carrying out the friction molding process in which they are pressed and shaped, the angle formed between the bottom portion 10 and the peripheral wall portion 11 of the first metal member 2 constituting the composite structure 1 can be easily made a right angle. Further, in the friction molding step, the first metal member 2 and the second metal member 3 are softened by the frictional heat of friction stirring, so that they can be easily shaped.

In particular, as shown in FIG. 12 , in press molding, the outer side of the corner formed by the bottom portion 10 and the peripheral wall portion 11 of the first metal member 2 is rounded. Therefore, it is difficult to make the corners of the back surface 10b of the bottom part 10 and the outer peripheral surface 11b of the peripheral wall part 11 at right angles (to form the corners between flat surfaces). However, according to the present embodiment, by performing the friction molding process, the outside of the corners of the first metal member 2 can be made right-angled (the corners are formed between flat surfaces), or can be made as close to right-angled as possible. .

Further, in the friction molding process according to the present embodiment, the outer peripheral surface H4 of the stirring pin H2 of the third rotary tool H is shaped (parallel) along the inner peripheral surface 31b of the molding surface 31, so that the stirring pin H2 and the peripheral wall The agitating pin H2 can be brought as close as possible to the peripheral wall portion 11 while being spaced apart from the portion 11 . As a result, the peripheral wall portion 11 can be uniformly pressed against the inner peripheral surface 31b of the molding surface 31 of the molding die 30 in the height direction, so that the molding can be shaped more accurately.

In particular, in the present embodiment, the outer peripheral surface H4 of the stirring pin H2 has a shape along the inner peripheral surface 31b of the molding surface 31, and the tip surface H3 has a shape (parallel) along the bottom surface 31a of the molding surface 31. , the stirring pin H2 can be brought close to the bottom portion 10 and the peripheral wall portion 11 as much as possible while keeping the agitation pin H2 away from the bottom portion 10 and the peripheral wall portion 11 . As a result, the shape can be formed more accurately.

Further, in this embodiment, in the preparation step, the hardness of the first metal member 2 is set higher than that of the second metal member 3, and in the first butt portion joining step, from the surface 3a of the second metal member 3 A rotating first rotating tool F is inserted, and friction stirring is performed in a state in which the stirring pin (proximal side pin F2) of the first rotating tool F is brought into slight contact with the first metal member 2 . As a result, the first butted portion J1 can be joined mainly by friction stir between the second metal member 3 and the first rotary tool F. Therefore, since the metal of the first metal member 2 having a large hardness is less likely to be mixed into the second metal member 3, it is possible to prevent defective joining caused by friction stir between metals of different types. Further, by slightly contacting the stirring pin of the first rotary tool F and the first metal member 2, the joint strength of the joint can be increased. Further, by increasing the hardness of the first metal member 2, the strength of the composite structure 1 can be increased.

In addition, in the first butt portion joining step according to the present embodiment, the first rotating tool F is used to bring the outer peripheral surface F5 of the proximal pin F2 into contact with the surface 3a of the second metal member 3 and the surface 12a of the flange portion 12. Since the friction stir welding is performed in a state where the joints are pressed, the occurrence of burrs can be suppressed. Further, according to the first rotary tool F, since the stepped pin stepped portion F21 of the proximal pin F2 is shallow and the outlet is wide, the plastic flow material is pushed by the step bottom face F21a and the plastic flow material is pushed through the pin step. It is easy to get out of the part F21. Therefore, even if the plastic flow material is pressed by the proximal pin F2, the plastic flow material is less likely to adhere to the outer peripheral surface F5 of the proximal pin F2. Therefore, the joint surface roughness can be reduced, and the joint quality can be preferably stabilized.

In addition, by performing the overlapped portion joining step, the overlapped portion J2 can be joined, so that the strength of the composite structure 1 can be increased. Further, by performing the overlapping portion joining step before the first butt portion joining step, it is possible to prevent the first metal member 2 and the second metal member 3 from being displaced in the first butt portion joining step.

In addition, in the overlapped portion joining step according to the present embodiment, the overlapped portion J2 is entirely moved by relatively moving the second metal member 3 from the central portion toward the outside so as to draw a spiral continuous trajectory in a plan view. Since friction stir is performed, the entire overlapped portion J2 can be easily joined. In addition, the second rotating tool G may be moved in any way in the overlapping portion joining step, but by spirally moving the second rotating tool G outward from the central portion, the first metal member 2 and the second metal member 2 It is possible to prevent the metal member 3 from being wrinkled.

In addition, in the overlapping portion joining process, friction stir welding is performed in a state in which only the stirring pin G2 is in contact with the first metal member 2 or the first metal member 2 and the second metal member 3, so that the friction stir device is affected. Load can be reduced.

Although the embodiments of the present invention have been described above, design changes are possible as appropriate. For example, in the present embodiment, the first butt joint joining process and the friction molding process are performed separately using different rotating tools, but they may be performed simultaneously using the same rotating tool. This can speed up the bonding cycle. Also, it is possible to save the trouble of exchanging the rotary tool. Also, the overlapping portion joining step and the first butt portion joining step may be performed continuously using one rotary tool. This saves the trouble of exchanging the rotary tool, thus speeding up the joining cycle.

[Second embodiment]
Next, a method for manufacturing a composite structure according to the second embodiment of the present invention will be described. As shown in FIG. 15, the method for manufacturing a composite structure according to this embodiment differs from the first embodiment in that the peripheral wall portion 11 of the first metal member 2A is tilted outward during the molding stage. In this embodiment, different parts will be mainly described.

In the method for manufacturing a composite structure according to the present embodiment, a preparation step, a placing step, a overlapping portion joining step, a first butt portion joining step, and a friction molding step are performed.

The preparation step is a step of preparing the first metal member 2A and the second metal member 3A. The first metal member 2A is formed by press-molding a plate-shaped material. The second metal member 3A is formed by extrusion molding, for example. As shown in FIG. 15, the peripheral wall portion 11 of the first metal member 2A is tilted outward with respect to the bottom portion 10 due to springback or the like. Further, the corner formed by the back surface 10b of the bottom portion 10 and the outer peripheral surface 11b of the peripheral wall portion 11 is rounded.

In the placing step, the second metal member 3A is placed in the concave portion 13 of the first metal member 2A while fixing the first metal member 2A to the mold 30 . The second metal member 3A presents a rectangular parallelepiped. The plate thickness dimension of the second metal member 3A is larger than the height dimension of the peripheral wall portion 11 . That is, when the second metal member 3A is placed in the concave portion 13 of the first metal member 2A, the surface 3a of the second metal member 3A is positioned higher than the surface 12a of the flange portion 12. As shown in FIG.

As shown in FIG. 15, the first butted portion J1 and the overlapping portion J2 are formed by the placing step. The first abutting portion J1 may include a case where there is a V-shaped cross-sectional gap between the outer peripheral surface 3c of the second metal member 3A and the inner peripheral surface 11a of the peripheral wall portion 11 as in the present embodiment. A gap Q is formed between the corner of the molding surface 31 and the corner of the first metal member 2A.

In the overlapped portion joining step, as shown in FIGS. 16 and 17, the overlapped portion J2 is friction stir welded in the same manner as in the first embodiment. As shown in FIG. 17, in the overlapping portion joining step, friction stir welding is performed at the outer peripheral edge of the second metal member 3A so that the plastic flow material does not flow out of the second metal member 3A.

In the first butt joint joining step, as shown in FIGS. 18 and 19, the first butt joint J1 is friction stir welded in the same manner as in the first embodiment. As shown in FIG. 19, in the first butt portion joining step, the first rotating tool F is used to slightly contact the stirring pins (the proximal pin F2 and the distal pin F3) with the first metal member 2, The outer peripheral surface F5 of the proximal pin F2 is relatively moved along the first abutting portion J1 while being in contact with the surface 3a of the second metal member 3A and the surface 12a of the flange portion 12 . In the first butt portion joining step, friction stir welding is performed while a plastic flow material is caused to flow into the gap formed in the first butt portion J1.

In the friction molding step, as shown in FIGS. 20 and 21, the third rotary tool H is used to press the first metal member 2A against the mold 30 in the same manner as in the first embodiment, thereby applying the first metal member 2A. shape. As shown in FIG. 21, in the friction molding process, friction stir is performed with the third rotating tool H slightly spaced from the bottom portion 10 and the peripheral wall portion 11, and the bottom portion is formed by the stirring pin H2 and the friction-stirred plastic flow material. 10 and the peripheral wall portion 11 are pressed against the bottom surface 31a and the inner peripheral surface 31b of the molding surface 31, respectively, to shape the first metal member 2. As shown in FIG. That is, the outer peripheral surface H4 of the stirring pin H2 and the inner peripheral surface 11a of the peripheral wall portion 11 are parallel or substantially parallel. Further, the tip surface H3 of the stirring pin H2 and the surface 10a of the bottom portion 10 are parallel or substantially parallel. In the friction molding process, it is preferable to press the first metal member 2A against the molding surface 31 so as to eliminate the gap Q (see FIG. 19). A plasticized region W3 is formed in the movement trajectory of the third rotating tool H. As shown in FIG. Once the third rotating tool H is made to go around along the first butted portion J1 to overlap the plasticized region W3, the third rotating tool H is separated from the surface 3a of the second metal member 3A at the end position EP3. A composite structure is formed by the above steps.

Approximately the same effects as those of the first embodiment can be obtained by the method of manufacturing a composite structure according to the present embodiment described above. As shown in FIG. 19, after the first metal member 2A is press-molded, springback occurs in the first metal member 2A. A gap Q may be formed. Even in such a case, by performing the friction molding process, the first metal member 2A can be shaped with the third rotating tool H, so that the bottom portion of the first metal member 2A constituting the composite structure The angle formed by 10 and peripheral wall portion 11 can be easily made a right angle. In particular, by performing the friction molding process according to the present embodiment, the outside of the corners of the first metal member 2A can be made right angles (the corners are formed between flat surfaces), or can be made as close to right angles as possible.

Also, as in this embodiment, the shape of the second metal member 3A does not necessarily have to be the same as the recess 13 of the first metal member 2A. In other words, there may be a gap in the first butted portion J1. Thereby, the second metal member 3A can be easily formed. Further, by making the height dimension of the second metal member 3A larger than the height dimension of the peripheral wall portion 11, it is possible to prevent metal shortage at the joint portion.

[Modification 1]
Next, Modification 1 of the present invention will be described. Modification 1 differs from the above-described embodiment in that the mold 30 and the mold 35 are selectively used.

As shown in FIG. 22, the molding die 35 is formed with a molding surface 36 having an inverted trapezoidal hollow portion. The molding surface 36 is composed of a bottom surface 36a and an inner peripheral surface 36b that rises obliquely outward from the bottom surface 36a. The angle formed by the bottom surface 36a and the inner peripheral surface 36b is an obtuse angle.

When the first metal member 2A is fixed to the molding die 35, the rear surface 10b of the bottom portion 10 and the bottom surface 36a of the molding surface 36 come into surface contact. Further, the outer peripheral surface 11b of the peripheral wall portion 11 and the inner peripheral surface 36b of the molding surface 36 are in surface contact. A gap Q is formed between the corner of the molding surface 36 and the corner of the first metal member 2A.

In the overlapped portion joining step, as shown in FIG. 23, the overlapped portion J2 is friction stir welded in the same manner as in the second embodiment.

In the first butt portion welding step, as shown in FIG. 24, the fourth rotary tool K is used to perform friction stir welding on the first butt portion J1 in substantially the same manner as in the first embodiment. The fourth rotating tool K is made of tool steel, and is composed of a cylindrical shoulder K1 and an agitating pin K2 hanging down from the bottom of the shoulder K1. A spiral groove is formed on the outer peripheral surface K3 of the stirring pin K2. For example, when rotating the fourth rotating tool K to the right, the spiral groove is set counterclockwise from the proximal side to the distal side.

When the fourth rotary tool K is rotated counterclockwise, it is preferable to set the spiral groove clockwise from the proximal side to the distal side. As a result, the plastic flow material is guided to the tip side by the stirring pin K2, so that the amount of metal overflowing to the outside of the metal members to be joined (the first metal member 2A and the second metal member 3A) can be reduced.

In the first butt portion joining step, the fourth rotary tool K is relatively moved along the first butt portion J1 while the bottom surface of the shoulder portion K1 is in contact with the surface 3a of the second metal member 3A. In addition, in the first butt portion joining step, friction stir welding is performed while the plastic flow material is allowed to flow into the gap of the first butt portion J1. After completing the first butt joint joining step, the first metal member 2A is removed from the mold 35 and fixed to the mold 30 .

In the friction molding step, although the specific illustration is omitted, as shown in FIG. 21, friction molding is performed in the same manner as in the second embodiment. That is, in the friction molding step, the peripheral wall portion 11 of the first metal member 2A tilted outward is pressed against the molding surface 31 to shape the first metal member 2A. Thereby, the angle formed by the bottom portion 10 of the first metal member 2A and the peripheral wall portion 11 can be made vertical.

Approximately the same effects as those of the first embodiment can be obtained by the method of manufacturing the composite structure according to Modification 1 described above. Also, the molds 30 and 35 may be used separately for each process. Further, in Modification 1, as shown in FIG. 22, the inner peripheral surface 36b of the molding surface 36 of the molding die 35 is inclined. can be fixed. In addition, as shown in FIG. 24, in the first butt portion joining step, the outer peripheral surface 11b of the peripheral wall portion 11 can be brought into surface contact with the inner peripheral surface 36b of the molding surface 36, so that friction stir welding can be performed stably. be able to.

[Modification 2]
Next, Modification 2 of the present invention will be described. Modification 2 is different from the other embodiments and modifications in that the corner formed by the bottom portion 10 and the peripheral wall portion 11 of the first metal member 2 is formed with an acute angle (undercut) using the forming die 37. . Modification 2 will mainly be described with respect to portions that are different from other embodiments and Modification 1. FIG.

In the manufacturing method of the composite structure according to the modified example, the preparation step, the placement step, and the first butt portion bonding step are performed in the same manner as in the first embodiment. As shown in FIG. 25, a mold 37 is used in the friction molding process of Modification 2. As shown in FIG. The molding die 37 is formed with a molding surface 38 having a trapezoidal hollow portion. The molding surface 38 is composed of a bottom surface 38a and an inner peripheral surface 38b that rises obliquely inward from the bottom surface 38a. The angle formed by the bottom surface 38a and the inner peripheral surface 38b is an acute angle.

In the friction molding step, a rotating third rotating tool H is inserted near the first butted portion J1 on the surface 3a of the second metal member 3 and relatively moved along the first butted portion J1. In the friction molding step, friction stirring is performed with the stirring pin H2 of the third rotating tool H slightly separated from the bottom portion 10 and the peripheral wall portion 11, and the bottom portion 10 and the peripheral wall are formed by the stirring pin H2 and the friction-stirred plastic flow material. The first metal member 2 is shaped by pressing the portion 11 against the bottom surface 38a and the inner peripheral surface 38b of the forming surface 38, respectively. The outer peripheral surface H4 of the stirring pin H2 and the inner peripheral surface 11a of the peripheral wall portion 11 are parallel or substantially parallel. Further, the tip surface H3 of the stirring pin H2 and the surface 10a of the bottom portion 10 are parallel or substantially parallel. As shown in FIGS. 25 and 26, in the friction molding process, it is preferable to shape the first metal member 2 by pressing it against the molding surface 38 so that the gap Q is eliminated.

As described above, substantially the same effects as those of the first embodiment can be obtained by the method of manufacturing a composite structure according to Modification 2 as well. Here, it is difficult to form an acute angle between the bottom portion 10 of the first metal member 2 and the peripheral wall portion 11 . When the first metal member 2 is press-molded, the bottom portion 10 and the peripheral wall portion 11 of the first metal member 2 cannot be formed at an acute angle due to die cutting.

However, according to the present embodiment, the composite structure is formed by performing a friction molding process in which the peripheral wall portion 11 of the first metal member 2 is pressed against the inner peripheral surface 38b of the molding surface 38 having an acute angle to form the shape. The angle formed by the bottom portion 10 of the first metal member 2 and the peripheral wall portion 11 can be easily made acute. Thus, composite structures with undercuts can be formed. Moreover, since the first metal member 2 and the second metal member 3 are softened by the frictional heat of friction stirring, they can be easily shaped.

[Third embodiment]
Next, a third embodiment of the invention will be described. As shown in FIG. 27, the composite structure 1B according to the third embodiment differs from the first embodiment in that the angle formed by the bottom portion 10 and the peripheral wall portion 11 is an obtuse angle. In the third embodiment, the description will focus on the parts that are different from the first embodiment.

A composite structure 1B according to the third embodiment is composed of a first metal member 2B and a second metal member 3B. The first metal member 2</b>B includes a bottom portion 10 , a peripheral wall portion 11 that rises obliquely outward from the peripheral portion of the bottom portion 10 , and a flange portion 12 that protrudes outward from the end portion of the peripheral wall portion 11 . The angle formed by the bottom portion 10 and the peripheral wall portion 11 is an obtuse angle. More specifically, the angle formed by the back surface 10b of the bottom portion 10 and the outer peripheral surface 11b of the peripheral wall portion 11 is also an obtuse angle.

The second metal member 3B is a plate-like member arranged in the recess 13 of the first metal member 2B. The second metal member 3B has substantially the same shape as the concave portion 13. As shown in FIG. The surface 3a of the second metal member 3B and the surface 12a of the flange portion 12 are flush with each other.

A first butted portion J1 where the inner peripheral surface 11a of the peripheral wall portion 11 and the outer peripheral surface 3c of the second metal member 3 are butted against each other is joined by friction stir to form a plasticized region W2. The plasticized region W2 is formed over the entire circumferential direction along the first butted portion J1.

A superposed portion J2 where the front surface 10a of the bottom portion 10 and the rear surface 3b of the second metal member 3 are butted against each other is joined by friction stir welding to form a plasticized region W1. The plasticized region W1 is formed over the entire overlapping portion J2. The plasticized region W3 is a plasticized region formed by a friction molding process, which will be described later.

Although the first metal member 2B and the second metal member 3B may be made of the same kind of metal, they are made of different materials in this embodiment. The first metal member 2B and the second metal member 3B may have the same hardness, but in the present embodiment, the hardness of the first metal member 2B is made higher than that of the second metal member 3B. ing. For example, in this embodiment, the first metal member 2B is made of an Al--Mg alloy (A5052 or the like). Further, for example, in the present embodiment, the second metal member 3B is made of Al (A1050 or the like).

Next, a method for manufacturing a composite structure according to this embodiment will be described. In the method for manufacturing a composite structure, a preparation step, a placing step, a overlapping portion joining step, a first butt portion joining step, and a friction molding step are performed.

The preparation step is a step of preparing the first metal member 2B and the second metal member 3B. The first metal member 2B is formed by press-molding a plate-shaped material. The second metal member 3B is formed by extrusion molding, for example. As shown in FIG. 28, the first metal member 2B is press-formed to form an obtuse angle between the bottom portion 10 and the peripheral wall portion 11, but the corner portions are rounded and curved.

The placing step is, as shown in FIG. 28, a step of placing the second metal member 3B on the first metal member 2B. In the placing step, first, the second metal member 3B is placed on the mold 35 . The mold 35 is the same as that used in Modification 1.

In the placing step, after fixing the first metal member 2B to the molding die 35, the second metal member 3B is fitted into the concave portion 13 of the first metal member 2B and placed. In the mounting step, the inner peripheral surface 11a of the peripheral wall portion 11 and the outer peripheral surface 3c of the second metal member 3B are butted against each other to form the first butting portion J1. Further, the surface 10a of the bottom portion 10 and the back surface 3b of the second metal member 3 are overlapped to form an overlapped portion J2. A gap P is formed between the corner of the mold 35 and the corner of the second metal member 3B. The surface 3a of the second metal member 3B and the surface 12a of the flange portion 12 are flush with each other. The same mold 35 may be used in the press molding process and the placing process. As a result, work can be saved.

In the overlapped portion joining step, as shown in FIG. 29, the overlapped portion J2 is friction stir welded in the same manner as in the first embodiment. In the overlapping portion joining step, friction stir welding is performed so that the second rotating tool G and the peripheral wall portion 11 do not come into contact with each other at the outer peripheral edge of the second metal member 3B.

In the first butt portion joining step, as shown in FIG. 30, the first butt portion J1 is friction stir welded in the same manner as in the first embodiment. In the first butt portion joining step, the first rotating tool F is used to slightly contact the stirring pins (the proximal pin F2 and the distal pin F3) with the first metal member 2B, and the outer periphery of the proximal pin F2 is moved. With the surface F5 in contact with the surface 3a of the second metal member 3B and the surface 12a of the flange portion 12, the surface F5 is relatively moved along the first abutting portion J1.

In the friction molding step, as shown in FIG. 31, the first metal member 2B is shaped by pressing the first metal member 2B against the mold 35 using the second rotating tool G in the same manner as in the first embodiment. A second rotary tool G is used in the friction molding process. The inclination angle of the outer peripheral surface G4 of the stirring pin G2 of the second rotating tool G is the same as the inclination angle of the inner peripheral surface 36b of the molding surface 36. As shown in FIG.

In the friction molding step, friction stir is performed with the second rotary tool G slightly separated from the bottom portion 10 and the peripheral wall portion 11, and the bottom portion 10 and the peripheral wall portion 11 are formed with the stirring pin G2 and the friction-stirred plastic flow material. The first metal member 2B is shaped by pressing against the bottom surface 36a and the inner peripheral surface 36b of the surface 36, respectively. The outer peripheral surface G4 of the stirring pin G2 and the inner peripheral surface 11a of the peripheral wall portion 11 are parallel or substantially parallel. Further, the tip surface G3 of the stirring pin G2 and the surface 10a of the bottom portion 10 are parallel or substantially parallel. In the friction molding process, it is preferable to press the first metal member 2B against the molding surface 36 so as to eliminate the gap P (see FIG. 30). A plasticized region W3 is formed in the movement trajectory of the second rotating tool G. As shown in FIG. After the second rotating tool G is made to go around the first butting portion J1 and overlap the plasticized region W3, the second rotating tool G is separated from the surface 3a of the second metal member 3B at the end position EP3. A composite structure 1B (see FIG. 27) is formed by the above steps.

Approximately the same effects as those of the first embodiment can be obtained by the method of manufacturing a composite structure according to the present embodiment described above. Here, it may be desired to form a composite structure by making the angle formed by the bottom portion 10 of the first metal member 2B and the peripheral wall portion 11 an obtuse angle. However, even if the first metal member 2B is formed by press molding, springback or the like occurs, so there is a possibility that the peripheral wall portion 11 may fall outward from the desired angle.

However, according to the present embodiment, the first metal member 2B that constitutes the composite structure 1B can be shaped by the second rotating tool G by performing the friction molding process. The angle formed by the bottom portion 10 and the peripheral wall portion 11 can be easily made obtuse (desired angle). In particular, by performing the friction molding process according to the present embodiment, the rear surface 10b and the outer peripheral surface 11b forming the outer side of the corner of the first metal member 2B are formed at a desired obtuse angle (the obtuse angle is formed between flat surfaces). can do.

Further, in the friction molding process, by making the outer peripheral surface G4 of the stirring pin G2 and the inner peripheral surface 36b of the molding die 35 parallel to each other, more accurate shaping can be achieved.

[Fourth embodiment]
Next, a method for manufacturing a composite structure according to the fourth embodiment of the present invention will be described. The composite structure according to this embodiment is the same as the third embodiment in that the angle formed by the bottom portion 10 and the peripheral wall portion 11 is an obtuse angle. On the other hand, it is different from the third embodiment in that a gap is formed between the peripheral wall portion 11 and the second metal member 3C when the mounting step is performed. In this embodiment, a description will be given centering on the parts that are different from the third embodiment.

In the method for manufacturing a composite structure, a preparation step, a placing step, a overlapping portion joining step, a first butt portion joining step, and a friction molding step are performed. In the preparation step, the first metal member 2C and the second metal member 3C are prepared. The second metal member 3C has a plate shape. The plate thickness dimension of the second metal member 3C is larger than the height dimension of the peripheral wall portion 11 .

In the placing step, as shown in FIG. 32, the second metal member 3C is placed on the first metal member 2C. The inner peripheral surface 11a of the peripheral wall portion 11 of the first metal member 2C and the outer peripheral surface 3c of the second metal member 3C are butted together to form a first butted portion J1. A gap having a V-shaped cross section is formed in the first abutting portion J1. A gap P is formed between the corner of the mold 35 and the corner of the first metal member 2C.

In the overlapped portion joining step, as shown in FIG. 33, the overlapped portion J2 is friction stir welded in the same manner as in the first embodiment. In the overlapping portion joining step, friction stir welding is performed at the outer peripheral edge of the second metal member 3C so that the plastic flow material does not flow out of the second metal member 3C.

In the first butt portion joining step, as shown in FIG. 34, the first butt portion J1 is friction stir welded in the same manner as in the first embodiment. In the first butt portion joining step, the first rotating tool F is used to slightly contact the stirring pins (the proximal pin F2 and the distal pin F3) with the first metal member 2B, and the outer periphery of the proximal pin F2 is moved. With the surface F5 in contact with the surface 3a of the second metal member 3C and the surface 12a of the flange portion 12, the surface F5 is relatively moved along the first abutting portion J1.

In the friction molding step, as shown in FIG. 35, the first metal member 2C is shaped by pressing the first metal member 2C against the mold 35 using the second rotary tool G in the same manner as in the third embodiment. A second rotary tool G is used in the friction molding process. The inclination angle of the outer peripheral surface G4 of the stirring pin G2 of the second rotating tool G is the same as the inclination angle of the inner peripheral surface 36b of the molding surface 36. As shown in FIG.

Approximately the same effects as those of the third embodiment can be obtained by the method of manufacturing a composite structure according to the present embodiment described above. Further, as shown in FIG. 32, even if there is a gap in the first butted portion J1 in the step of placing, in the first butted portion joining step, the first butted portion J1 is allowed to flow while the plastic flow material flows into the gap. J1 can be friction stir welded. Further, since the plate thickness dimension of the second metal member 3C is made larger than the height dimension of the peripheral wall portion 11, it is possible to prevent metal shortage at the joint portion.

Although the embodiments and modifications of the present invention have been described above, design changes can be made as appropriate without departing from the gist of the present invention. For example, the overlapping portion joining step may be omitted. In the friction molding process, the outer peripheral surface and tip end surface of the stirring pin of the rotating tool were made parallel or substantially parallel to the bottom surface and inner peripheral surface of the mold, respectively. You may make it parallel or substantially parallel only with an internal peripheral surface.

1 composite structure 2 first metal member 3 second metal member F rotating tool (first rotating tool)
F1 Base shaft F2 Base end pin F3 Distal end pin F4 Distal end surface F5 Peripheral surface G Rotating tool (second rotating tool)
G2 Stirring pin G3 Tip surface G4 Peripheral surface H Rotating tool (third rotating tool)
H2 Stirring pin H3 Tip surface H4 Peripheral surface K Rotary tool (fourth rotary tool)
K1 Shoulder part K2 Stirring pin K3 Tip surface J1 First butt part J2 Overlapping part

Claims (10)

A method for manufacturing a composite structure by performing friction stir, comprising:
a first metal member having a concave portion composed of a bottom portion and a frame-shaped peripheral wall portion rising from a peripheral edge portion of the bottom portion, the first metal member including a flange portion projecting outward from an end portion of the peripheral wall portion; a preparation step of preparing a second metal member arranged in the recess of
The second metal member is placed in the recess of the first metal member, and the inner peripheral surface of the peripheral wall portion of the first metal member and the outer peripheral surface of the second metal member are butted against each other to form a first abutting portion. a placing step to
a first butt part joining step of friction stir welding the first butt part using a rotating rotary tool;
While inserting a rotary tool that rotates from the surface of the second metal member, the rotary tool is relatively moved along the first abutment portion, and the molding surface of the mold arranged on the back side of the first metal member is pressed against the mold surface. a friction molding step of pressing and shaping the peripheral wall portion of the first metal member,
A method of manufacturing a composite structure, wherein in the friction molding step, the angle formed by the bottom surface of the molding surface of the mold and the inner peripheral surface of the mold is formed at a right angle or an acute angle. 2. The method of manufacturing a composite structure according to claim 1, wherein in the friction molding step, the outer peripheral surface of the stirring pin of the rotating tool is parallel to the inner peripheral surface of the molding surface. In the preparation step, the hardness of the first metal member is set higher than the hardness of the second metal member,
In the first butt portion joining step, a rotating rotating tool is inserted from the surface of the second metal member, and friction stir is performed in a state where the stirring pin of the rotating tool is slightly in contact with the first metal member. 3. The method for manufacturing a composite structure according to claim 1 or 2, characterized by: In the placing step, the surface of the bottom portion of the first metal member and the back surface of the second metal member are overlapped to form an overlapping portion,
Before performing the first butt joint joining step, a rotating tool that rotates is inserted from the surface of the second metal member, and only the stirring pin of the rotating tool is moved to the second metal member only, or the first metal member and 4. The composite structure according to any one of claims 1 to 3, further comprising an overlapping portion joining step of joining the overlapping portion by friction stir while being in contact with the second metal member. Production method. In the overlapped portion joining step, a rotating tool is inserted into the central portion of the surface of the second metal member, and relatively moved outward from the central portion so as to draw a continuous helical trajectory in plan view. 5. The method of manufacturing a composite structure according to claim 4, wherein the entire polymerization portion is friction-stirred. 6. The method for manufacturing a composite structure according to claim 4, wherein the overlapping portion joining step and the first butt portion joining step are performed continuously using a single rotary tool. In the first butt portion joining step, a proximal side pin and a distal side pin are provided, the taper angle of the proximal side pin is set larger than the taper angle of the distal side pin, and the outer circumference of the proximal side pin Friction stir is performed by using a rotating tool having a step-like stepped portion formed on the surface thereof, with the outer peripheral surface of the base end side pin in contact with the surface of the second metal member. 6. The method of manufacturing a composite structure according to any one of claims 1 to 5. In the first butt portion joining step, a rotary tool having a shoulder portion and an agitating pin hanging down from the bottom surface of the shoulder portion is used, and the bottom surface of the shoulder portion is in contact with the surface of the second metal member. 6. The method for manufacturing a composite structure according to any one of claims 1 to 5, wherein friction stirring is performed. In the placing step, when the second metal member is placed on the first metal member, the surface of the second metal member is the same as the surface of the flange portion of the first metal member, or 9. The method of manufacturing a composite structure according to any one of claims 1 to 8, wherein the thickness of the second metal member is set so as to be higher than the surface of the flange portion. 2. The method of manufacturing a composite structure according to claim 1, wherein said first butt joint joining step and said friction forming step are performed simultaneously with a single rotating tool.

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