JP2021133386A - Method for manufacturing composite structure - Google Patents

Abstract

To easily make an angle formed by a bottom part and a peripheral wall part of a first metal member constituting a composite structure, a right angle or an acute angle.SOLUTION: A method for manufacturing a composite structure includes: a preparation step for preparing a first metal member 2, and a second metal member 3 to be arranged in a recess 13 of the first metal member 2; a placement step for placing the second metal member 3 in the recess 13 of the first metal member 2 and forming a first butting part J1; a first butting part joining step for joining the first butting part J1 by using a rotating rotary tool; and a friction molding step in which a third rotary tool H rotating from a surface 3a of the second metal member 3 is relatively moved along the first butting part J1 while inserting the third rotary tool H, and in which a peripheral wall part 11 of the first metal member 2 is pressed and shaped against a molding surface 31 of a molding die 30 arranged on a rear side of the first metal member 2. In the friction molding step, an angle formed by a bottom part 31a and an inner peripheral surface 31b of the molding surface 31 of the molding die 30 is formed to be a right angle or an acute angle.SELECTED DRAWING: Figure 14

Description

The present invention relates to a method for producing a composite structure.

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

Japanese Unexamined Patent Publication No. 2019-214193

A relatively thin composite structure may be formed by using a first metal member having a plate thickness of about several millimeters. In such a case, in consideration of moldability, it is preferable to press-mold the metal plate to form the box-shaped first metal member. However, in the case of press molding, springback occurs, 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 between the bottom portion of the first metal member constituting the composite structure and the peripheral wall portion at a right angle, the peripheral wall portion is tilted outward by springback after press forming. In addition, the peripheral wall portion may tilt outward due to softening due to frictional heat during friction stir welding or pressing force of the rotating tool. In particular, in the case of press molding, the corners between the bottom and the peripheral wall are bent strictly in a round shape, so that the corners between the back surface of the bottom of the first metal member and the outer peripheral surface of the peripheral wall are at right angles to each other. That is extremely difficult.

Further, for example, when it is desired to make an acute angle between the bottom portion and the peripheral wall portion of the first metal member constituting 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 formed by the bottom portion of the first metal member and the peripheral wall portion is an acute angle (undercut).

From such a viewpoint, the present invention provides a method for manufacturing a composite structure in which the angle formed by the bottom portion and the peripheral wall portion of the first metal member constituting the composite structure can be easily made a right angle or an acute angle. Make it an issue.

In order to solve such a problem, the present invention is a method for manufacturing a composite structure in which a composite structure is manufactured by performing frictional stirring, in which a bottom portion and a frame-shaped peripheral wall portion rising from a peripheral portion of the bottom portion are used. A first metal member having a recess to be formed and having a flange portion protruding outward from an end portion of the peripheral wall portion and a second metal member arranged in the recess of the first metal member are prepared. In the preparatory step, 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 is abutted against the outer peripheral surface of the second metal member. A mounting step of forming a butt portion, a first butt portion joining step of frictionally stirring and joining the first butt portion using a rotating rotation tool, and a rotating tool that rotates from the surface of the second metal member are inserted. While moving the rotating tool relative to the first butt portion, the peripheral wall portion of the first metal member is pressed against the molding surface of the molding mold arranged on the back side of the first metal member to form a friction molding. The friction molding step includes a step, and is characterized in that the angle formed by the bottom surface and the inner peripheral surface of the molding surface of the molding die is formed at a right angle or a sharp angle.

According to such a manufacturing method, the first metal constituting the composite structure is formed by performing a friction molding step of pressing the peripheral wall portion of the first metal member against the molding surface of the molding mold having a right angle or an acute angle. 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. Further, since the first metal member and the second metal member are softened by the frictional heat of friction stir welding, the shape can be easily formed.

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

According to such a manufacturing method, the peripheral wall portion can be uniformly pressed against the inner peripheral surface of the molded surface in the height direction, so that the shaping can be performed more accurately.

Further, in the preparatory step, the hardness of the first metal member is set higher than the hardness of the second metal member, and in the first butt stir welding step, a rotation tool that rotates from the surface of the second metal member is used. It is preferable to perform friction stir welding with the stirring pin of the rotating tool inserted and slightly in contact with the first metal member.

According to such a manufacturing method, the first butt portion can be joined mainly by friction stir welding between the second metal member and the rotating tool. As a result, the metal of the first metal member having a high hardness is less likely to be mixed into the second metal member, so that it is possible to prevent poor joining due to frictional agitation between metals of different grades.

Further, in the above-described 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 a polymerized portion, and the first butt portion joining step is performed before the step is performed. A rotating tool that rotates from the surface of the second metal member is inserted, and friction stir welding is performed with only the stirring pin of the rotating tool in contact with only the second metal member or the first metal member and the second metal member. It is preferable to include a polymerized part joining step of joining the polymerized parts by means of.

According to such a production method, since the polymerized portions can be joined, the strength of the composite structure can be increased. Further, in the first butt joint joining step, it is possible to prevent the position shift between the first metal member and the second metal member.

Further, in the polymerization portion joining step, a rotation tool is inserted into the central portion of the surface of the second metal member, and the rotary tool is relatively moved from the central portion to the outside so as to draw a spiral continuous locus in a plan view. It is preferable to stir the entire polymerized portion by friction.

According to such a production method, the entire polymerized portion can be easily bonded. Further, by moving the rotating tool spirally from the central portion to the outside, it is possible to prevent wrinkles from being generated in the first metal member and the second metal member.

Further, it is preferable that the polymerization part joining step and the first butt part joining step are continuously performed by using one rotation tool.

According to such a manufacturing method, it is not necessary to replace the rotating tool for each process, so that the joining cycle can be shortened.

Further, in the first butt joint joining step, the proximal end side pin and the distal end side pin are provided, the taper angle of the proximal end side pin is set to be larger than the taper angle of the distal end side pin, and the proximal end side pin is set. It is preferable to perform friction stir welding in a state where the outer peripheral surface of the base end side pin is in contact with the surface of the second metal member by using a rotating tool having a stepped step portion formed on the outer peripheral surface of the metal member.

According to such a manufacturing method, since the plastic fluid material can be pressed on the outer peripheral surface of the base end side pin in the first butt joint joining step, the generation of burrs can be suppressed.

Further, in the first butt portion joining step, a rotating tool provided with a shoulder portion and a stirring pin hanging from the bottom surface of the shoulder portion was used to bring the bottom surface of the shoulder portion into contact with the surface of the second metal member. It is preferable to perform friction stir welding in this state.

According to such a manufacturing method, since the plastic fluid material can be pressed on the bottom surface of the shoulder portion in the first butt portion joining step, the generation of burrs can be suppressed.

Further, in the above-described step, when the second metal member is placed on the first metal member, is the surface of the second metal member 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 that the position is higher than the surface of the flange portion.

According to such a manufacturing method, it is possible to prevent the joint portion of the first butt portion from becoming short of metal.

Further, it is preferable that the first butt joint joining step and the friction forming step are simultaneously performed by one rotating tool.

According to such a manufacturing method, since each step can be performed at the same time, the joining cycle can be shortened. In addition, since it is not necessary to replace the rotation 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 and the peripheral wall portion of the first metal member 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 sectional view of the 1st rotation tool. It is sectional drawing which shows the 1st modification of the 1st rotation tool. It is sectional drawing which shows the 2nd modification of the 1st rotation tool. It is sectional drawing which shows the 3rd modification of the 1st rotation tool. It is a perspective view which shows the composite structure which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the composite structure which concerns on 1st Embodiment. It is sectional drawing which shows the preparation process and the placement process of the manufacturing method of the composite structure which concerns on 1st Embodiment. It is a top view which shows the polymerization part joining process of the manufacturing method of the composite structure which concerns on 1st Embodiment. It is sectional drawing which shows the polymer part joining process of the manufacturing method of the composite structure which concerns on 1st Embodiment. It is a top view which shows the 1st butt part joining process of the manufacturing method of the composite structure which concerns on 1st Embodiment. It is sectional drawing which shows the 1st butt part joining process of the manufacturing method of the composite structure which concerns on 1st Embodiment. It is a top view which shows the friction molding process of the manufacturing method of the composite structure which concerns on 1st Embodiment. It is sectional drawing which shows the friction molding process of the manufacturing method of the composite structure which concerns on 1st Embodiment. It is sectional drawing which shows the preparation process and the placement process of the manufacturing method of the composite structure which concerns on 2nd Embodiment of this invention. It is a top view which shows the polymerization part joining process of the manufacturing method of the composite structure which concerns on 2nd Embodiment. It is sectional drawing which shows the polymer part joining process of the manufacturing method of the composite structure which concerns on 2nd Embodiment. It is a top view which shows the 1st butt part joining process of the manufacturing method of the composite structure which concerns on 2nd Embodiment. It is sectional drawing which shows the 1st butt part joining process of the manufacturing method of the composite structure which concerns on 2nd Embodiment. It is a top view which shows the friction molding process of the manufacturing method of the composite structure which concerns on 2nd Embodiment. It is sectional drawing which shows the friction molding process of the manufacturing method of the composite structure which concerns on 2nd Embodiment. It is sectional drawing which shows the preparation process and the placement process of the manufacturing method of the composite structure which concerns on modification 1. FIG. It is sectional drawing which shows the polymer part joining process of the manufacturing method of the composite structure which concerns on modification 1. FIG. It is sectional drawing which shows the 1st butt part joining process of the manufacturing method of the composite structure which concerns on modification 1. FIG. It is sectional drawing which shows the friction molding process of the manufacturing method of the composite structure which concerns on modification 2. FIG. It is sectional drawing which shows after the friction molding process of the manufacturing method of the composite structure which concerns on modification 2. It is sectional drawing which shows the composite structure which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the preparation process and the placement process of the manufacturing method of the composite structure which concerns on 3rd Embodiment. It is sectional drawing which shows the polymer part joining process of the manufacturing method of the composite structure which concerns on 3rd Embodiment. It is sectional drawing which shows the 1st butt part joining process of the manufacturing method of the composite structure which concerns on 3rd Embodiment. It is sectional drawing which shows the friction molding process of the manufacturing method of the composite structure which concerns on 3rd Embodiment. It is sectional drawing which shows the preparation process and the placement process of the manufacturing method of the composite structure which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the polymer part joining process of the manufacturing method of the composite structure which concerns on 4th Embodiment. It is sectional drawing which shows the 1st butt part joining process of the manufacturing method of the composite structure which concerns on 4th Embodiment. It is sectional drawing which shows the friction molding process of the manufacturing method of the composite structure which concerns on 4th Embodiment.

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

First, the first rotation tool used in the method for manufacturing the composite structure according to the present embodiment will be described. As shown in FIG. 1, the first rotation tool F is made of, for example, tool steel, and includes a base shaft portion F1, a base end side pin F2, and a tip end side pin F3. The base end side pin F2 and the tip end side pin F3 form a "stirring pin". The base shaft portion F1 has a columnar shape and is a portion connected to the main shaft of the friction stir welder.

The base end side pin F2 is continuous with the base shaft portion F1 and is tapered toward the tip end. The proximal end side pin F2 has a truncated cone shape. The taper angle A of the base end side pin F2 may be appropriately set, 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 welding becomes large. The taper angle A is larger than the taper angle B of the tip side pin F3, which will be described later. As shown in FIG. 2, a stepped pin step portion F21 is formed on the outer peripheral surface F5 of the base end side pin F2 over the entire height direction. The pin step portion F21 is formed in a spiral shape in a clockwise or counterclockwise direction. That is, the pin step portion F21 has a spiral shape when viewed in a plane and a step shape when viewed from a side surface. For example, when the first rotation tool F is rotated clockwise, the pin step portion F21 is set counterclockwise from the base end side to the tip end side.

When the first rotation tool F is rotated counterclockwise, it is preferable to set the pin step portion F21 clockwise from the base end side to the tip end side. As a result, the plastic fluid material is guided to the tip side by the pin step portion F21, so that the metal overflowing to the outside of the metal member 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 and F21c of the adjacent pin step portions F21 is appropriately set according to the step angle C and the height Y1 of the step side surface F21b described later.

The height Y1 of the step side surface F21b may be appropriately set, and is set to, for example, 0.1 to 0.4 mm. 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 step portions (the number of pin step portions F21 in contact with the metal member to be joined) also decreases.

The step angle C formed by the step bottom surface F21a and the step side surface F21b may be appropriately set, but is set to, for example, 85 to 120 °. The step bottom surface F21a is parallel to the horizontal plane in this embodiment. The step bottom surface F21a may be inclined in the range of -5 ° to 15 ° with respect to the horizontal plane from the rotation axis of the tool toward the outer peripheral direction (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 step side surface F21b, the step angle C, and the angle of the step bottom surface F21a with respect to the horizontal plane are such that the plastic fluid does not stay inside the pin step portion F21 and adhere to the outside during friction stir welding. The surface roughness of the joint is appropriately set so that the plastic fluid material can be pressed by the step bottom surface F21a to reduce the roughness of the joint surface.

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

When the first rotation tool F is rotated counterclockwise, it is preferable to set the spiral groove F31 clockwise from the base end side to the tip end side. As a result, the plastic fluid material is guided to the tip side by the spiral groove F31, so that the metal overflowing to the outside of the metal member 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 vertices F31c and F31c of the adjacent spiral grooves F31 is defined as the length X2. The height of the spiral side surface F31b is defined as the height Y2. The spiral angle D composed of the spiral bottom surface F31a and the spiral side surface F31b is formed at, for example, 45 to 90 °. The spiral groove F31 has a role of increasing frictional heat by coming into contact with the metal member to be joined and guiding the plastic fluid material to the tip side. Further, the first rotation tool F may be attached to a robot arm having a rotation driving means such as a spindle unit at the tip thereof.

The design of the first rotation tool F can be changed as appropriate. FIG. 3 is a side view showing a first modification of the first rotation tool of the present invention. As shown in FIG. 3, in the first rotation tool FA according to the first modification, the step angle C formed by the step bottom surface F21a of the pin step portion F21 and the step side surface F21b is 85 °. The step bottom surface F21a is parallel to the horizontal plane. As described above, the step bottom surface F21a is parallel to the horizontal plane, and the step angle C may be an acute angle within a range in which the plastic fluid material stays in the pin step portion F21 during friction stir welding and escapes to the outside without adhering. ..

FIG. 4 is a side view showing a second modification of the first rotation tool of the present invention. As shown in FIG. 4, in the first rotation tool FB according to the second modification, the step angle C of the pin step portion F21 is 115 °. The step bottom surface F21a is parallel to the horizontal plane. As described above, the step bottom surface F21a may be parallel to the horizontal plane, and the step angle C may be obtuse within the range in which the step bottom surface F21a functions as the pin step portion F21.

FIG. 5 is a side view showing a third modification of the first rotation tool of the present invention. As shown in FIG. 5, in the first rotation tool FC according to the third modification, the step bottom surface F21a is inclined 10 ° upward with respect to the horizontal plane from the rotation axis of the tool toward the outer peripheral direction. The step side surface F21b is parallel to the vertical surface. As described above, the step bottom surface F21a may be formed so as to be inclined upward from the horizontal plane from the rotation axis of the tool toward the outer peripheral direction within a range in which the plastic fluid material can be pressed during friction stir welding. The same effect as that of the following embodiment can be obtained by the first to third modifications of the first rotation tool.

In this embodiment, the first rotation tool F is attached to a friction stir device that can move in the horizontal direction and the vertical direction. The first rotation tool F may be attached to a robot arm having a rotation driving means such as a spindle unit at its tip.

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

As shown in FIGS. 6 and 7, the first metal member 2 has a bottom portion 10, a peripheral wall portion 11, and a flange portion 12, and has a box shape. The plate thickness of the first metal member 2 is substantially constant, and is about several millimeters in the present embodiment. The bottom portion 10 is a plate-shaped portion having a rectangular shape in a plan view. The peripheral wall portion 11 is a rectangular frame-shaped wall that rises from the peripheral edge portion of the bottom portion 10. The flange portion 12 projects outward from the tip end portion of the peripheral wall portion 11. A recess 13 is formed in 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 vertical.

The second metal member 3 is a plate-shaped member arranged in the recess 13 of the first metal member 2. The second metal member 3 has substantially the same shape as the recess 13. The surface 3a of the second metal member 3 and the surface 12a of the flange portion 12 are flush with each other. The first abutting portion J1 in which 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 together is joined by friction stir welding to form a plasticized region W2. The plasticized region W2 is formed along the first butt portion J1 over the entire circumferential direction.

The polymerization portion J2 in which the front surface 10a of the bottom portion 10 and the back surface 3b of the second metal member 3 are overlapped is joined by friction stir welding to form a plasticized region W1. The plasticized region W1 is formed over the entire polymerization portion J2. The plasticized region W3 is a plasticized region formed in the friction forming step described later.

The first metal member 2 and the second metal member 3 may be formed of the same type of metal, but in the present embodiment, they are formed of different material types. Further, the first metal member 2 and the second metal member 3 may have the same hardness, but in the present embodiment, the hardness of the first metal member 2 is made higher than the hardness of the second metal member 3. 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 the present embodiment, the second metal member 3 is made of Al (A1050 or the like). In the present specification, the hardness refers to Brinell hardness, which can be measured by a method according to JIS Z 2243.

Next, a method for manufacturing the composite structure according to the present embodiment will be described. In the method for manufacturing a composite structure, a preparation step, a mounting step, a polymerization section joining step, a first butt 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 base material. The second metal member 3 is formed by, for example, extrusion molding. As shown in FIG. 8, the first metal member 2 is formed by press molding 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.

As shown in FIG. 8, the mounting step is a step of mounting the second metal member 3 on the first metal member 2. In the mounting step, first, the second metal member 3 is installed in the molding die 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 so as to be a hollow portion of a rectangular parallelepiped. A plurality of clamps 40 are provided on the surface of the molding die 30. The clamp 40 is a member that presses the flange portion 12 and immobilly restrains the first metal member 2 to the molding die 30.

In the mounting step, after the first metal member 2 is fixed to the molding die 30, the second metal member 3 is fitted into the recess 13 of the first metal member 2 and mounted. By 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 abutted to form the first abutting portion J1. Further, the front surface 10a of the bottom portion 10 and the back surface 3b of the second metal member 3 are overlapped to form the overlapping portion J2. A gap P is formed between the corner portion of the molding die 30 and the corner portion 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 molding die 30 may be used in the press molding step and the mounting step. As a result, work labor can be saved.

The polymerization section joining step is a step of friction stir welding of the polymerization section J2 as shown in FIGS. 9 and 10. In the polymerization section joining step, as shown in FIG. 10, the second rotation tool G is used. The second rotating tool G is made of tool steel and has a connecting portion G1 and a stirring pin G2. The connecting portion G1 is a portion mounted on the rotating shaft of the friction stir welding device. The stirring pin G2 hangs coaxially 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. A spiral groove is formed on the outer peripheral surface G4 of the stirring pin G2. For example, when the second rotation tool G is rotated clockwise, the spiral groove is set counterclockwise from the base end side to the tip end side.

When the second rotation tool G is rotated counterclockwise, it is preferable to set the spiral groove clockwise from the base end side to the tip end side. As a result, the plastic fluid material is guided to the tip side by the stirring pin G2, so that the metal that overflows to the outside of the metal member to be joined (first metal member 2 and second metal member 3) can be reduced.

In the polymerization section joining step, as shown in FIG. 9, the stirring pin G2 of the second rotating tool G that rotates clockwise is made 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 rotation tool G is continuously moved relative to the outside from the central portion to friction stir weld the polymerized portion J2. A plasticized region W1 is formed in the movement locus of the second rotation tool G. In the polymerization portion joining step, the second rotation tool G is relatively moved so as to form a spiral movement locus from the central portion to the outside while overlapping the end portions in the width direction of the plasticized region W1.

As shown in FIG. 10, in the polymerization section 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. Further, in the polymerization section joining step, only the stirring pin G2 is brought into contact with the first metal member 2 and the second metal member 3. That is, friction stir welding is performed with the base end side of the stirring pin G2 exposed. The stirring pin G2 may be brought into contact with only the second metal member 3 to perform the polymerization section joining step. In this case, the stirring pin G2 is plastically fluidized by the frictional heat of the second metal member 3, and the polymerization portion J2 is joined.

In the polymerization section 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 on the outer peripheral edge of the second metal member 3. This makes it possible to prevent the metal of the first metal member 2 from being mixed into the second metal member 3 in the step of joining the polymerized portion. When the end position EP1 set at the corner of the second metal member 3 is reached, the second rotation tool G is separated from the second metal member 3.

In the present embodiment, the polymerization part joining step is performed by the second rotation tool G, but the first rotation tool F, the third rotation tool H or the fourth rotation tool K described later, or another rotation tool is used. May be good. Further, in the polymerization section joining step, the route of the rotation tool may be set so as to have another movement locus.

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

As shown in FIG. 12, in the first butt joint joining step, the base end side pin F2 is slightly brought into contact with the first metal member 2 to perform friction stir welding. Further, in the first butt joint joining step, friction stir welding is performed in a state where the outer peripheral surface F5 of the base end side pin F2 of the first rotation 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 locus of the first rotation tool F. After the first rotation tool F is made to go around along the first butt portion J1 and the plasticized region W2 is overlapped, the first rotation 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 is performed by the first rotation tool F, but the second rotation tool G, the third rotation tool H or the fourth rotation tool K described later, or another rotation tool is used. You may.

As shown in FIGS. 13 and 14, the friction molding step is a step of pressing the first metal member 2 against the molding die 30 using the third rotation tool H to shape the first metal member 2. 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 mounted on the rotating shaft of the friction stir welding device. The stirring pin H2 hangs coaxially from the connecting portion H1 and exhibits 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. A spiral groove is formed on the outer peripheral surface H4 of the stirring pin H2. For example, when the third rotation tool H is rotated clockwise, the spiral groove is set counterclockwise from the base end side to the tip end side.

When the third rotation tool H is rotated counterclockwise, it is preferable to set the spiral groove clockwise from the base end side to the tip end side. As a result, the plastic fluid material is guided to the tip side by the stirring pin H2, so that the metal overflowing to the outside of the second metal member 3 can be reduced.

In the friction forming step, the stirring pin H2 is inserted perpendicularly to the surface 3a at the start position SP3 set in the vicinity of the first butt portion J1 on the surface 3a of the second metal member 3. Then, the third rotation tool H is relatively moved along the first butt portion J1.

As shown in FIG. 14, in the friction molding step, friction stirring is performed with the stirring pin H2 of the third rotation tool H slightly separated from the bottom portion 10 and the peripheral wall portion 11, and the stirring pin H2 and the frictionally agitated plasticity are performed. The first metal member 2 is formed 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 a fluid material, respectively. 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 to each other. 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 to each other. In the friction molding step, 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 locus of the third rotation tool H. After the third rotation tool H is made to go around along the first butt portion J1 and the plasticized region W3 is overlapped, the third rotation 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 the present embodiment, the friction forming step is performed by the third rotation tool H, but the first rotation tool F, the second rotation tool G, the fourth rotation tool K described later, or another rotation tool may be used. ..
At this time, the rotation center axis of each rotation tool may be appropriately tilted so that the stirring pin of each rotation tool and the inner peripheral surface of the molding surface are parallel to each other. Further, in the friction forming step, it is preferable that the stirring pin of the rotary tool and the peripheral wall portion 11 are separated from each other, but if the amount is small, they may be brought into contact with each other.

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 surfaces 31 (bottom surface 31a and inner peripheral surface 31b) of the molding die 30 which are at right angles. By performing the friction forming step of pressing and shaping each of them, the angle formed by 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 stir welding, so that the shape can be easily formed.

In particular, as shown in FIG. 12, in press molding, the outside of the corner portion composed of the bottom portion 10 and the peripheral wall portion 11 of the first metal member 2 is bent round. As a result, it is difficult to make the corners of the back surface 10b of the bottom portion 10 and the outer peripheral surface 11b of the peripheral wall portion 11 at right angles (form the corner portions between the planes). However, according to the present embodiment, by performing the friction forming step, the outside of the corner portion of the first metal member 2 can be made a right angle (the corner portion is formed by the planes), or the corner portion can be made as close to a right angle as possible. ..

Further, in the friction molding step according to the present embodiment, the stirring pin H2 and the peripheral wall are formed by forming the outer peripheral surface H4 of the stirring pin H2 of the third rotation tool H along the inner peripheral surface 31b of the molding surface 31 (parallel). The stirring pin H2 can be brought as close as possible to the peripheral wall portion 11 in a state where the portion 11 is separated 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 shaping can be performed 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. With the stirring pin H2 separated from the bottom portion 10 and the peripheral wall portion 11, the stirring pin H2 can be brought as close as possible to the bottom portion 10 and the peripheral wall portion 11. As a result, it is possible to shape the shape even more accurately.

Further, in the present embodiment, the hardness of the first metal member 2 is set higher than the hardness of the second metal member 3 in the preparatory step, and from the surface 3a of the second metal member 3 in the first butt stir welding step. The rotating first rotation tool F is inserted, and friction stirring is performed in a state where the stirring pin (base end side pin F2) of the first rotation tool F is slightly in contact with the first metal member 2. As a result, the first butt portion J1 can be joined mainly by friction stir welding between the second metal member 3 and the first rotating tool F. Therefore, since the metal of the first metal member 2 having a high hardness is less likely to be mixed into the second metal member 3, it is possible to prevent poor joining due to frictional agitation between metals of different grades. Further, the joint strength of the joint portion can be increased by slightly contacting the stirring pin of the first rotation tool F with the first metal member 2. Further, by increasing the hardness of the first metal member 2, the strength of the composite structure 1 can be increased.

Further, in the first butt portion joining step according to the present embodiment, the first rotation tool F is used to bring the outer peripheral surface F5 of the base end side pin F2 into contact with the surface 3a of the second metal member 3 and the surface 12a of the flange portion 12. Since friction stir welding is performed in this state, the generation of burrs can be suppressed. Further, according to the first rotation tool F, the stepped pin step portion F21 of the base end side pin F2 is shallow and the outlet is wide, so that the plastic fluid material is pressed by the step bottom surface F21a and the plastic fluid material is pin stepped. It is easy to pull out to the outside of the part F21. Therefore, even if the plastic fluid material is pressed by the base end side pin F2, the plastic fluid material is unlikely to adhere to the outer peripheral surface F5 of the base end side pin F2. Therefore, the roughness of the joint surface can be reduced, and the joint quality can be suitably stabilized.

Further, by performing the polymerization section joining step, the polymerization section J2 can be joined, so that the strength of the composite structure 1 can be increased. Further, by performing the polymerization part joining step before the first butt part joining step, it is possible to prevent the position shift between the first metal member 2 and the second metal member 3 in the first butt part joining step.

Further, in the polymerization section joining step according to the present embodiment, the entire polymerization section J2 is moved relative to the outside from the central portion of the second metal member 3 so as to draw a continuous spiral locus in a plan view. Since friction stir welding is performed, the entire polymerization section J2 can be easily joined. Further, in the polymerization section joining step, the second rotation tool G may be moved in any way, but by moving the second rotation tool G spirally from the central portion to the outside, the first metal member 2 and the second rotation tool G are moved. It is possible to prevent wrinkles from being generated on the metal member 3.

Further, in the bonding part joining step, the friction stir welding is performed in a state where 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 welding device is acted on. The load can be reduced.

Although the embodiment of the present invention has been described above, the design can be changed as appropriate. For example, in the present embodiment, the first butt joint joining step and the friction forming step are performed separately by using different rotation tools, but they may be performed simultaneously by using the same rotation tool. As a result, the joining cycle can be accelerated. Moreover, the trouble of exchanging the rotation tool can be saved. Further, the polymerization part joining step and the first butt part joining step may be continuously performed by using one rotation tool. This saves the trouble of exchanging the rotation tool, so that the joining cycle can be accelerated.

[Second Embodiment]
Next, a method for producing the 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 the present embodiment is different from the first embodiment in that the peripheral wall portion 11 of the first metal member 2A is tilted outward at the molding stage. In this embodiment, the differences will be mainly described.

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

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

In the mounting step, the second metal member 3A is mounted in the recess 13 of the first metal member 2A while fixing the first metal member 2A to the molding die 30. The second metal member 3A exhibits 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 recess 13 of the first metal member 2A, the surface 3a of the second metal member 3A is located higher than the surface 12a of the flange portion 12.

As shown in FIG. 15, the first butt portion J1 and the polymerization portion J2 are formed by the mounting step. The first butt portion J1 may include a case where there is a gap having a V-shaped cross section 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. Further, a gap Q is formed between the corner portion of the molding surface 31 and the corner portion of the first metal member 2A.

In the polymerization section joining step, as shown in FIGS. 16 and 17, the polymerization section J2 is friction-stir welded in the same manner as in the first embodiment. As shown in FIG. 17, in the polymerization section joining step, friction stir welding is performed on the outer peripheral edge of the second metal member 3A so that the plastic fluid material does not flow out to the outside of the second metal member 3A.

In the first butt portion joining step, as shown in FIGS. 18 and 19, the first butt portion J1 is friction-stir welded in the same manner as in the first embodiment. As shown in FIG. 19, in the first butt joint joining step, the first rotation tool F is used, and the stirring pin (base end side pin F2 and tip end side pin F3) is slightly brought into contact with the first metal member 2 while being slightly contacted. The outer peripheral surface F5 of the base end side pin F2 is relatively moved along the first butt portion J1 in a state of 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 the plastic fluid material is allowed to flow into the gap formed in the first butt portion J1.

In the friction forming step, as shown in FIGS. 20 and 21, the first metal member 2A is pressed against the forming die 30 by using the third rotation tool H in the same manner as in the first embodiment to apply the first metal member 2A. Shape. As shown in FIG. 21, in the friction forming step, friction stirring is performed with the third rotation tool H slightly separated from the bottom portion 10 and the peripheral wall portion 11, and the bottom portion is formed by the stirring pin H2 and the frictionally agitated plastic fluid material. The first metal member 2 is formed by pressing the 10 and the peripheral wall portion 11 against the bottom surface 31a and the inner peripheral surface 31b of the molding surface 31, respectively. 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 10 are parallel or substantially parallel. In the friction forming step, it is preferable to press the first metal member 2A against the forming surface 31 so that the gap Q (see FIG. 19) is eliminated. A plasticized region W3 is formed in the movement locus of the third rotation tool H. After the third rotation tool H is made to go around along the first butt portion J1 and the plasticized region W3 is overlapped, the third rotation tool H is separated from the surface 3a of the second metal member 3A at the end position EP3. The composite structure is formed by the above steps.

The method for producing the composite structure according to the present embodiment described above can also obtain substantially the same effect as that of the first embodiment. As shown in FIG. 19, after the first metal member 2A is press-molded, springback occurs in the first metal member 2A. Therefore, when the mounting process is performed, the first metal member 2A is between the molding die 30 and the first metal member 2A. A gap Q may be formed. Even in such a case, the first metal member 2A can be shaped by the third rotation tool H by performing the friction forming step, so that the bottom portion of the first metal member 2A constituting the composite structure can be formed. The angle formed by the peripheral wall portion 11 and the peripheral wall portion 11 can be easily made a right angle. In particular, by performing the friction forming step according to the present embodiment, the outside of the corner portion of the first metal member 2A can be made a right angle (the corner portion is formed by the planes), or the corner portion can be made as close to a right angle as possible.

Further, as in the present 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. That is, there may be a gap in the first butt portion J1. As a result, the second metal member 3A can be easily molded. 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 the metal shortage of the joint portion.

[Modification 1]
Next, a modification 1 of the present invention will be described. Modification 1 is different from the above-described embodiment in that the molding die 30 and the molding die 35 are used properly.

As shown in FIG. 22, the molding die 35 is formed with a molding surface 36 having a hollow portion having an inverted trapezoidal shape. The molding surface 36 is composed of a bottom surface 36a and an inner peripheral surface 36b that obliquely rises 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 back surface 10b of the bottom portion 10 and the bottom surface 36a of the molding surface 36 come into surface contact with each other. Further, the outer peripheral surface 11b of the peripheral wall portion 11 and the inner peripheral surface 36b of the molding surface 36 come into surface contact with each other. Further, a gap Q is formed between the corner portion of the molding surface 36 and the corner portion of the first metal member 2A.

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

In the first butt portion joining step, as shown in FIG. 24, friction stir welding is performed on the first butt portion J1 using the fourth rotation tool K 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 columnar shoulder portion K1 and a stirring pin K2 hanging from the bottom surface of the shoulder portion K1. A spiral groove is formed on the outer peripheral surface K3 of the stirring pin K2. For example, when the fourth rotation tool K is rotated clockwise, the spiral groove is set counterclockwise from the base end side to the tip end side.

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

In the first butt portion joining step, the fourth rotation tool K is relatively moved along the first butt portion J1 in a state where the bottom surface of the shoulder portion K1 is in contact with the surface 3a of the second metal member 3A. Further, in the first butt portion joining step, friction stir welding is performed while the plastic fluid 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 molding die 35, and the first metal member 2A is fixed to the molding die 30.

In the friction molding step, although 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 forming step, the peripheral wall portion 11 of the first metal member 2A tilted outward is pressed against the forming surface 31 to shape the first metal member 2A. As a result, the angle formed by the bottom portion 10 of the first metal member 2A and the peripheral wall portion 11 can be made vertical.

The method for producing the composite structure according to the first modification described above can also obtain substantially the same effect as that of the first embodiment. Further, the molding dies 30 and 35 may be used properly for each process. Further, in the first modification, as shown in FIG. 22, since the inner peripheral surface 36b of the molding surface 36 of the molding mold 35 is inclined, the first metal member 2A in which the peripheral wall portion 11 is inclined outward is stably stabilized. Can be fixed. Further, as shown in FIG. 24, in the first butt joint 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 is stably performed. be able to.

[Modification 2]
Next, a modification 2 of the present invention will be described. The modified example 2 is different from other embodiments and modified examples in that the corner portion formed by the bottom portion 10 and the peripheral wall portion 11 of the first metal member 2 is made an acute angle (undercut) by using the molding die 37. .. In the second modification, the parts different from the other embodiments and the first modification will be mainly described.

In the method for manufacturing the composite structure according to the modified example, the preparation step, the mounting step, and the first butt joint joining step are performed in the same manner as in the first embodiment. As shown in FIG. 25, the molding die 37 is used in the friction molding step of the modification 2. 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 obliquely rises 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 forming step, the third rotating tool H, which rotates in the vicinity of the first butt portion J1 on the surface 3a of the second metal member 3, is inserted and relatively moved along the first butt portion J1. In the friction forming step, friction stirring is performed with the stirring pin H2 of the third rotation 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 used with the stirring pin H2 and the frictionally agitated plastic fluid 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 molding 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 to each other. Further, the tip surface H3 of the stirring pin H2 and the surface 10a of the bottom 10 are parallel or substantially parallel. As shown in FIGS. 25 and 26, in the friction molding step, it is preferable to press the first metal member 2 against the molding surface 38 so as to eliminate the gap Q.

As described above, the effect of substantially the same as that of the first embodiment can be obtained by the method for producing the composite structure according to the modified example 2. Here, it is difficult to make the angle formed by the bottom portion 10 of the first metal member 2 and the peripheral wall portion 11 an acute angle. 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 have an acute angle due to die cutting.

However, according to the present embodiment, the composite structure is formed by performing a friction molding step of pressing the peripheral wall portion 11 of the first metal member 2 against the inner peripheral surface 38b of the molded surface 38 having an acute angle to shape the composite structure. The angle formed by the bottom portion 10 of the first metal member 2 and the peripheral wall portion 11 can be easily made an acute angle. That is, it is possible to form a composite structure having an undercut. Further, since the first metal member 2 and the second metal member 3 are softened by the frictional heat of friction stir welding, the shape can be easily formed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. As shown in FIG. 27, the composite structure 1B according to the third embodiment is different 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 parts different from the first embodiment will be mainly described.

The 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 2B includes a bottom portion 10, a peripheral wall portion 11 that obliquely rises outward from the peripheral edge portion of the bottom portion 10, and a flange portion 12 that projects 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-shaped member arranged in the recess 13 of the first metal member 2B. The second metal member 3B has substantially the same shape as the recess 13. The surface 3a of the second metal member 3B and the surface 12a of the flange portion 12 are flush with each other.

The first abutting portion J1 in which 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 together is joined by friction stir welding to form a plasticized region W2. The plasticized region W2 is formed along the first butt portion J1 over the entire circumferential direction.

The polymerization portion J2 in which the front surface 10a of the bottom portion 10 and the back surface 3b of the second metal member 3 are butted together is joined by friction stir welding to form a plasticized region W1. The plasticized region W1 is formed over the entire polymerization portion J2. The plasticized region W3 is a plasticized region formed in the friction forming step described later.

The first metal member 2B and the second metal member 3B may be formed of the same type of metal, but in the present embodiment, they are formed of different material types. Further, 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 the hardness 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 formed of Al (A1050 or the like).

Next, a method for manufacturing the composite structure according to the present embodiment will be described. In the method for manufacturing a composite structure, a preparation step, a mounting step, a polymerization section joining step, a first butt 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 forms a plate-shaped base material by press molding. The second metal member 3B is formed by, for example, extrusion molding. As shown in FIG. 28, in the first metal member 2B, the angle formed by the bottom portion 10 and the peripheral wall portion 11 is obtuse by press molding, but the corner portion is formed to be round and curved.

As shown in FIG. 28, the mounting step is a step of mounting the second metal member 3B on the first metal member 2B. In the mounting step, first, the second metal member 3B is installed on the molding die 35. The mold 35 is the same as that used in the first modification.

In the mounting step, after the first metal member 2B is fixed to the molding die 35, the second metal member 3B is fitted into the recess 13 of the first metal member 2B and mounted. By 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 abutted to form the first abutting portion J1. Further, the front surface 10a of the bottom portion 10 and the back surface 3b of the second metal member 3 are overlapped to form the overlapping portion J2. A gap P is formed between the corner portion of the molding die 35 and the corner portion 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 molding die 35 may be used in the press molding step and the mounting step. As a result, work labor can be saved.

In the polymerization section joining step, as shown in FIG. 29, the polymerization section J2 is friction-stir welded in the same manner as in the first embodiment. In the polymerization section 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 on 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 joint joining step, the outer circumference of the base end side pin F2 is used while the stirring pin (base end side pin F2 and tip end side pin F3) is slightly brought into contact with the first metal member 2B by using the first rotation tool F. The surface F5 is relatively moved along the first butt portion J1 in a state where the surface F5 is in contact with the surface 3a of the second metal member 3B and the surface 12a of the flange portion 12.

In the friction molding step, as shown in FIG. 31, the first metal member 2B is pressed against the molding die 35 by using the second rotation tool G in the same manner as in the first embodiment to shape the first metal member 2B. In the friction forming step, the second rotation tool G is used. The inclination angle of the outer peripheral surface G4 of the stirring pin G2 of the second rotation tool G is the same as the inclination angle of the inner peripheral surface 36b of the molding surface 36.

In the friction forming step, friction stirring is performed with the second rotating 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 by the stirring pin G2 and the frictionally agitated plastic fluid material. The first metal member 2B is formed 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 to each other. Further, the front end surface G3 of the stirring pin G2 and the surface 10a of the bottom portion 10 are parallel or substantially parallel to each other. In the friction molding step, it is preferable to press the first metal member 2B against the molding surface 36 so that the gap P (see FIG. 30) is eliminated. A plasticized region W3 is formed in the movement locus of the second rotation tool G. After the second rotation tool G is made to go around along the first butt portion J1 and the plasticized region W3 is overlapped, the second rotation tool G is separated from the surface 3a of the second metal member 3B at the end position EP3. The composite structure 1B (see FIG. 27) is formed by the above steps.

The method for producing the composite structure according to the present embodiment described above can also obtain substantially the same effect as that of the first embodiment. Here, there is a case where it is 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 obtuse. However, even if the first metal member 2B is formed by press molding, springback or the like occurs, so that the peripheral wall portion 11 may fall outward from a desired angle.

However, according to the present embodiment, since the first metal member 2B can be shaped by the second rotation tool G by performing the friction forming step, the first metal member 2B constituting the composite structure 1B can be formed. The angle formed by the bottom portion 10 and the peripheral wall portion 11 can be easily set to an obtuse angle (desired angle). In particular, by performing the friction molding step according to the present embodiment, the back surface 10b and the outer peripheral surface 11b forming the outer side of the corner portion of the first metal member 2B are made into a desired obtuse angle (the corner portions of the obtuse angle are formed between the planes). can do.

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

[Fourth Embodiment]
Next, a method for producing the composite structure according to the fourth embodiment of the present invention will be described. The composite structure according to the present 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 differs 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, the parts different from the third embodiment will be mainly described.

In the method for manufacturing a composite structure, a preparation step, a mounting step, a polymerization section joining step, a first butt 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 mounting step, as shown in FIG. 32, the second metal member 3C is mounted 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 abutted to form the first abutting portion J1. A gap having a V-shaped cross section is formed in the first butt portion J1. Further, a gap P is formed between the corner portion of the molding die 35 and the corner portion of the first metal member 2C.

In the polymerization section joining step, as shown in FIG. 33, the polymerization section J2 is friction-stir welded in the same manner as in the first embodiment. In the polymerization part joining step, friction stir welding is performed on the outer peripheral edge of the second metal member 3C so that the plastic fluid does not flow out to the outside 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 joint joining step, the outer circumference of the base end side pin F2 is used while the stirring pin (base end side pin F2 and tip end side pin F3) is slightly brought into contact with the first metal member 2B by using the first rotation tool F. The surface F5 is relatively moved along the first butt portion J1 in a state where the surface F5 is in contact with the surface 3a of the second metal member 3C and the surface 12a of the flange portion 12.

In the friction forming step, as shown in FIG. 35, the first metal member 2C is pressed against the forming die 35 by using the second rotation tool G in the same manner as in the third embodiment to shape the first metal member 2C. In the friction forming step, the second rotation tool G is used. The inclination angle of the outer peripheral surface G4 of the stirring pin G2 of the second rotation tool G is the same as the inclination angle of the inner peripheral surface 36b of the molding surface 36.

The method for producing the composite structure according to the present embodiment described above can also obtain substantially the same effect as that of the third embodiment. Further, as shown in FIG. 32, even if there is a gap in the first butt portion J1 at the stage of the mounting process, in the first butt portion joining step, the first butt portion is made to flow the plastic fluid material into the gap. J1 can be friction stir welded. Further, since the plate thickness dimension of the second metal member 3C is larger than the height dimension of the peripheral wall portion 11, it is possible to prevent the joint portion from becoming short of metal.

Although the embodiments and modifications of the present invention have been described above, the design can be appropriately changed within a range not contrary to the gist of the present invention. For example, the step of joining the polymerized portion may be omitted. Further, in the friction molding step, the outer peripheral surface and the tip surface of the stirring pin of the rotary tool are made parallel to or substantially parallel to the bottom surface and the inner peripheral surface of the molding die, respectively. Only the inner peripheral surface may be parallel or substantially parallel.

1 Composite structure 2 First metal member 3 Second metal member F Rotation tool (first rotation tool)
F1 Base shaft F2 Base end side pin F3 Tip side pin F4 Tip surface F5 Peripheral surface G Rotation tool (second rotation tool)
G2 Stirring pin G3 Tip surface G4 Peripheral surface H Rotation tool (3rd rotation tool)
H2 Stirring pin H3 Tip surface H4 Peripheral surface K Rotation tool (4th rotation tool)
K1 Shoulder part K2 Stirring pin K3 Tip surface J1 First butt part J2 Polymerization part

Claims (10)

A method for manufacturing a composite structure in which a composite structure is manufactured by friction stir welding.
A first metal member having a recess formed by a bottom portion and a frame-shaped peripheral wall portion rising from the peripheral edge portion of the bottom portion, and having a flange portion protruding outward from the end portion of the peripheral wall portion, and the first metal member. A preparatory step for preparing the 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 abutted to form the first butt portion. Placement process and
The first butt joint joining step of friction stir welding the first butt portion using a rotating rotary tool,
While inserting the rotating tool that rotates from the surface of the second metal member, the rotating tool is relatively moved along the first butt portion, and the rotating tool is moved to the molding surface of the molding die arranged on the back side of the first metal member. Including a friction molding step of pressing the peripheral wall portion of the first metal member to shape it,
In the friction molding step, a method for producing a composite structure, characterized in that the angle formed by the bottom surface and the inner peripheral surface of the molding surface of the molding mold is formed at a right angle or an acute angle. The method for manufacturing a composite structure according to claim 1, wherein in the friction molding step, the outer peripheral surface of the stirring pin of the rotary tool is made parallel to the inner peripheral surface of the molding surface. In the preparatory step, the hardness of the first metal member is set higher than the hardness of the second metal member.
In the first butt joint joining step, a rotating tool that rotates from the surface of the second metal member is inserted, and friction stir welding is performed with the stirring pin of the rotating tool slightly in contact with the first metal member. The method for producing a composite structure according to claim 1 or 2, wherein the composite structure is characterized. In the above-described step, the front surface of the bottom portion of the first metal member and the back surface of the second metal member are overlapped to form a superposition portion.
Before performing the first butt joint joining step, a rotating tool that rotates from the surface of the second metal member is inserted, and only the stirring pin of the rotating tool is used only for the second metal member, or the first metal member and the first metal member. The composite structure according to any one of claims 1 to 3, further comprising a polymerized part joining step of joining the polymerized parts by friction stir welding in contact with the second metal member. Production method. In the polymerization section joining step, a rotation tool is inserted into the central portion of the surface of the second metal member, and the rotary tool is relatively moved from the central portion to the outside so as to draw a continuous spiral locus in a plan view. The method for producing a composite structure according to claim 4, wherein the entire polymerized portion is agitated by friction. The method for producing a composite structure according to claim 4 or 5, wherein the polymerization section joining step and the first butt joining step are continuously performed using one rotating tool. In the first butt joint joining step, the proximal end side pin and the distal end side pin are provided, the taper angle of the proximal end side pin is set to be larger than the taper angle of the distal end side pin, and the outer circumference of the proximal end side pin is set. 1. The method for producing a composite structure according to any one of claims 5. In the first butt joint joining step, a rotating tool provided with a shoulder portion and a stirring pin hanging 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. The method for producing a composite structure according to any one of claims 1 to 5, wherein friction stir welding is performed. In the above-described 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 the surface of the flange portion is the same. The method for 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. The method for manufacturing a composite structure according to claim 1, wherein the first butt joint joining step and the friction molding step are simultaneously performed by one rotating tool.

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