Bonding structure and bonding method

Abstract

A joint structure (1) includes a first member (11), a second member (12) including an opposing portion (32) facing the first member (12) in a thickness direction, and a plurality of joint portions (13) for joining the first member (11) and the second member (12) to be disposed along the opposing portion (32). The plurality of joint portions (13) includes a pair of end joint portions (13A) located at both ends of the opposing portion (32), and an intermediate joint portion (13B) located between the pair of end joint portions (13A) and having a lower joining strength than the end joint portions (13A). The end joint portions (13A) include fastening bodies (40) mechanically joining the first member (11) and the second member (12). The intermediate joint portion (13B) includes a friction stir portion (51) joining the first member (11) and the second member (12) by friction stirring.

Description

Technical Field

[0001] The present invention relates to a joining structure and a joining method for obtaining the joining structure, wherein the joining structure is formed by joining a first member and a second member through a plurality of joining portions. Background Technology

[0002] In the manufacture of structures such as aircraft, railway vehicles, or automobiles, it is sometimes necessary to stack and join two or more components, including those made of metal or resin. One known method of this joining is the use of rivets (fasteners).

[0003] For example, Patent Document 1 discloses a technique for joining two sheet materials, including an upper plate and a lower plate, using a combination of rivets and welding. Specifically, in Patent Document 1, after a rivet is driven through the upper plate, molten metal is formed by irradiating the head of the rivet with a welding laser. Thus, the upper plate and the lower plate are joined together by the molten metal and the rivet.

[0004] In Patent Document 1, the aforementioned combination of rivets and welding is applied to multiple joints in the roof panel of a vehicle body. This is intended to ensure sufficient joint strength of the roof panel. However, since rivets and welding are required at all joints, there are concerns about increased manufacturing costs and labor time.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2014-226698 Summary of the Invention

[0008] The present invention was made in view of the aforementioned circumstances, and its object is to provide a joint structure that has both sufficient joint strength and can be manufactured at a relatively low cost.

[0009] To address the aforementioned issues, one aspect of the present invention relates to a joining structure comprising: a first member; a second member including an opposing portion facing the first member in the thickness direction; and a plurality of joining portions disposed along the opposing portion for joining the first member and the second member; wherein the plurality of joining portions include: a pair of end joining portions located at both ends of the opposing portion; and an intermediate joining portion located between the pair of end joining portions and having a joining strength lower than that of the end joining portions; wherein the end joining portions include a fastener for mechanically joining the first member and the second member, and the intermediate joining portion includes a friction stirring portion for joining the first member and the second member by friction stirring.

[0010] Another aspect of the present invention relates to a joining method for joining a first member and a second member comprising opposing portions facing the first member in the thickness direction, comprising: an end joining step of forming a pair of end joining portions located at both ends of the opposing portions; and an intermediate joining step of forming an intermediate joining portion between the pair of end joining portions with a joining strength lower than that of the end joining portions; wherein, in the end joining step, a joining portion comprising a fastener and a friction stirring portion is formed as the end joining portion, the fastener mechanically joining the first member and the second member, and the friction stirring portion joining the first member and the second member by friction stirring; in the intermediate joining step, a joining portion comprising a friction stirring portion but not a fastener is formed as the intermediate joining portion, the friction stirring portion joining the first member and the second member by friction stirring; the end joining step and the intermediate joining step are performed using the same friction stirring joining device. Attached Figure Description

[0011] Figure 1 This is a perspective view showing a joining structure according to an embodiment of the present invention.

[0012] Figure 2 It is a cross-sectional view showing the structure of the end joint.

[0013] Figure 3 It is a cross-sectional view showing the structure of the intermediate joint.

[0014] Figure 4 This is a schematic diagram showing the overall configuration of the friction stirring joint device used in the manufacture of the joint structure.

[0015] Figure 5 This is a cross-sectional view showing the first process (preparation step) of forming the end joint.

[0016] Figure 6 This is a cross-sectional view showing the second process (positioning step) of forming the end joint.

[0017] Figure 7 This is a cross-sectional view showing the third process (pressing step) in forming the end joint.

[0018] Figure 8A This is a cross-sectional view showing the state at the beginning of the fourth process (setting step) for forming the end joint.

[0019] Figure 8B This is a cross-sectional view showing the state at the end of the fourth process (setting step).

[0020] Figure 9It is a simplified cross-sectional view that brings together the processes of forming the intermediate joint.

[0021] Figure 10 This is a perspective view showing a first modified example of the described embodiment.

[0022] Figure 11 This is a perspective view showing a second variation of the described embodiment.

[0023] Figure 12 This is a perspective view showing the third variation of the described embodiment.

[0024] Figure 13 This is a cross-sectional view showing the fourth variation of the described embodiment. Detailed Implementation

[0025] [Joint Structure]

[0026] Figure 1 This is a perspective view showing a joining structure 1 according to an embodiment of the present invention. As shown in the figure, the joining structure 1 includes a first member 11, a second member 12, and a plurality of joints 13 that join the first member 11 and the second member 12. The joining structure 1 can be used, for example, in structures such as aircraft, railway vehicles, or automobiles.

[0027] The first component 11 is a component constituting the outer plate of the structure, and is formed into a flat plate with a certain thickness. The first component 11 has a surface 21 that forms the outer side of the outer plate and a back surface 22 located on the opposite side of the surface 21.

[0028] The second member 12 is a skeleton member with an L-shaped cross-section, including a main body 31 and a flange 32. Hereinafter, the direction of the ridge line where the main body 31 and the flange 32 intersect will be defined as the front-back direction, and the direction orthogonal to this front-back direction will be defined as the left-right direction. The main body 31 is a plate-like body erected from the back surface 22 of the first member 11 in a direction perpendicular to that surface, and is formed to extend along the back surface 22 in the front-back direction. The flange 32 is provided to extend from the end of the main body 31 on the side of the first member 11 in either the left or right direction, and abuts against the back surface 22 of the first member 11. In this embodiment, the flange 32 is provided to extend to the right and abuts against the back surface 22 of the first member 11. In other words, the flange 32 overlaps with the first member 11 in a layered manner in the thickness direction. The thickness of the second component 12, that is, the thickness of the main body 31 and the flange 32, can be the same as or different from the thickness of the first component 11. In addition, the flange 32 is equivalent to the "opposing part" in this invention.

[0029] The boundary between the main body 31 and the flange 32 is set as a bend 33 that is bent at an angle of approximately 90 degrees. In other words, the second member 12 is a skeleton member that includes one bend 33 and is formed in an L-shaped cross section.

[0030] The flange portion 32 is formed into a rectangular shape having a long side extending in the front-rear direction and a short side extending in the left-right direction. In other words, the flange portion 32 is an ended and strip-shaped member having a front end E1 and a rear end E2. The surface of the flange portion 32 on the side of the first member 11 functions as an abutting surface 32a that abuts against the back surface 22 of the first member 11.

[0031] Both the first component 11 and the second component 12 are formed of thermoplastic composite material. Specifically, the first component 11 and the second component 12 are formed of fiber-reinforced thermoplastic resin comprising a substrate and a plurality of reinforcing fibers, wherein the substrate comprises thermoplastic resin and the plurality of reinforcing fibers are impregnated with the substrate.

[0032] Examples of thermoplastic resins that can be used as substrates for the first component 11 and the second component 12 include polypropylene (PP), polyethylene (PE), polyamide (PA), polystyrene (PS), polyaryletherketone (PEAK), polyacetal (POM), polycarbonate (PC), polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), ABS resin, and thermoplastic epoxy resin. Furthermore, examples of reinforcing fibers impregnated with the substrate include carbon fiber, glass fiber, ceramic fiber, metal fiber, or organic fiber.

[0033] Multiple joints 13 are arranged side-by-side in a straight line along the flange 32 in the front-rear direction. Specifically, the multiple joints 13 have a pair of end joints 13A at the front and rear, and multiple intermediate joints 13B, specifically three, located between the pair of end joints 13A. The end joints 13A are joints that join the front or rear end of the flange 32, that is, the portion near the front end E1 or rear end E2 of the flange 32, to the first member 11. The intermediate joints 13B are joints that join the middle portion of the flange 32 in the front-rear direction, that is, the portion of the flange 32 excluding the front and rear ends, to the first member 11. As described below, the end joints 13A and intermediate joints 13B have different joint structures from each other, such that the joint strength of the end joints 13A is higher than that of the intermediate joints 13B.

[0034] [Structure of each joint]

[0035] Figure 2This is a cross-sectional view showing the structure of the end joint 13A. As shown in the figure, the end joint 13A is a joint that joins the front or rear end of the flange 32 of the second member 12 with the overlapping portion 15 of the first member 11, and includes a rivet 40 and a friction stirring part 50. In other words, the end joint 13A is a joint that securely joins the overlapping portion 15 by the combination of the rivet 40 and the friction stirring part 50. Hereinafter, the side from the first member 11 to the second member 12 will be referred to as "upper" and the opposite side as "lower", but this is only for the convenience of explanation and is not intended to limit the posture of the joint structure 1.

[0036] The friction stirring section 50 is a joint formed by the solidification of material that is frictionally stirred in the overlapping section 15. The friction stirring section 50 is formed into a cylindrical shape corresponding to the area pressed in by the rotating tool 101, which will be described later. The friction stirring section 50 does not necessarily need to reach the lower first member 11, but in this embodiment, its depth is set to a value greater than the thickness of the second member 12 (flange 32) so that the friction stirring section 50 reaches the first member 11. The friction stirring section 50 has a cylindrical side peripheral surface 50a at a position corresponding to the boundary between the friction stirring section 50 and the non-friction stirring section (base material area) on its outer periphery. Furthermore, the friction stirring section 50 has a circular bottom surface 50b at a position corresponding to the boundary between the friction stirring section 50 and the lower non-friction stirring section (base material area).

[0037] The rivet 40 is a fastener that is driven into the overlapping portion 15 in a mechanical manner to join the first member 11 and the second member 12. In this embodiment, a self-piercing rivet 40 is used as the rivet 40, which is driven into a material without a pre-drilled hole without penetrating through. The material of the rivet 40 can be selected from suitable materials as long as it has the strength to be driven into the overlapping portion 15. For example, metallic materials such as titanium or high-strength steel, or resin materials such as thermoplastic resin or thermoplastic composites, can be used as the material of the rivet 40. In the case where a titanium rivet 40 is used to join fiber-reinforced resin materials as in this embodiment, a titanium alloy rivet such as Ti-6AL-4V is preferred.

[0038] After the rivet 40 is pressed in by the rotating tool 101 (described later), in other words, after frictional agitation in the overlapping portion 15, it is driven into the overlapping portion 15. In this driven state, the rivet 40 has a circular plate-shaped head 41 that is pressed against the upper side of the flange portion 32 of the second member 12, and a hollow shaft portion 42 that gradually widens in diameter and extends downward from the lower side of the head 41. The shaft portion 42 is arranged to pass through the second member 12 (flange portion 32) and extend to the middle of the thickness direction of the first member 11. The shaft portion 42 has a distal end portion 42a that widens in diameter further away from the head 41 and protrudes to the outside of the friction agitation portion 50. This distal end portion 42a functions as an interlocking part that fixes the first member 11 and the second member 12 (flange portion 32) in a pressed state. That is, the first component 11 and the second component 12 are fixed in a mutually pressed state by being sandwiched between an interlocking part consisting of a distal end 42a protruding to the outside of the friction stirring part 50 and a head 41 disposed on the upper side of the second component 12.

[0039] Figure 3 This is a cross-sectional view showing the structure of the intermediate joint 13B. As shown in the figure, the intermediate joint 13B is a joint where the middle portion of the flange portion 32 of the second member 12 in the front-rear direction is joined to the overlapping portion 16 of the first member 11, and includes a friction stirring portion 51. Unlike the end joint 13A, the intermediate joint 13B does not include a rivet 40. Figure 2 Since rivet 40 is not used in the intermediate joint 13B, the joint strength of the intermediate joint 13B is lower than that of the end joint 13A.

[0040] The friction stirring section 51 in the intermediate joint 13B is a joint formed by the solidification of material that is frictionally stirred in the overlapping section 16, similar to the friction stirring section 50 in the end joint 13A described above. It is formed as a cylinder with a depth greater than the thickness of the second member 12 (flange 32). The friction stirring section 51 has a cylindrical side circumferential surface 51a at a position corresponding to the boundary between the friction stirring section 51 and the non-friction stirring section (base material region) on its outer periphery. Furthermore, the friction stirring section 51 has a circular bottom surface 51b at a position corresponding to the boundary between the friction stirring section 51 and the non-friction stirring section (base material region) on its lower side.

[0041] [Friction stirring coupling device]

[0042] The joint structure 1, including the aforementioned end joint 13A and intermediate joint 13B, is used Figure 4The friction stirring coupling device M shown in the figure is manufactured using this method. As indicated, the friction stirring coupling device M includes: a rotary tool 101; a tool drive unit 102 that drives the rotary tool 101 to rotate and move up and down; and a controller C that controls the movement of the tool drive unit 102. Furthermore, in... Figure 4 The bid includes "up" and "down" directions, but this is only for ease of explanation and does not intend to limit the actual posture of the rotating tool 101.

[0043] The rotating tool 101 is supported by a tool fixing part (not shown). This tool fixing part can serve as, for example, the distal end of a multi-joint robot. A back pad member 115 is disposed facing the lower end face of the rotating tool 101. A first member 11 and a second member 12, serving as engagement objects, are disposed between the rotating tool 101 and the back pad member 115. Furthermore, in Figure 4 The diagram illustrates an example of the arrangement of the components when forming the end joint 13A. That is, Figure 4 The illustrated joining object is the overlapping portion 15 where the flange portions 32 of the first member 11 and the second member 12 overlap in the front-rear direction.

[0044] The rotating tool 101 includes a pin member 111, a shoulder member 112, a clamping member 113, and a spring 114. The pin member 111 is a cylindrical member that is arranged such that its axis extends in the vertical direction. The pin member 111 can rotate about the axis as a pivot R, and can move forward and backward (lift and lower) along the pivot R in the vertical direction.

[0045] The shoulder member 112 is configured to cover the outer periphery of the pin member 111. That is, the shoulder member 112 is a cylindrical member with a hollow portion into which the pin member 111 is inserted. The axis of the shoulder member 112 is coaxial with the axis of the pin member 111 (rotation axis R). The shoulder member 112 can rotate about the same rotation axis R as the pin member 111, and can move forward and backward (up and down) along the rotation axis R. Thus, both the shoulder member 112 and the pin member 111, which is inserted into the hollow portion, can rotate about the rotation axis R and can move relative to each other along the rotation axis R. That is, the pin member 111 and the shoulder member 112 can not only move up and down simultaneously along the rotation axis R, but also can perform independent movements such as one descending while the other rises.

[0046] The clamping member 113 is configured to cover the outer periphery of the shoulder member 112. That is, the clamping member 113 is a cylindrical member with a hollow portion into which the shoulder member 112 is inserted. The axis of the clamping member 113 is also coaxial with the rotation axis R. Although the clamping member 113 does not rotate about the axis, it can move forward and backward (lift and lower) along the rotation axis R. During friction stirring of the pin member 111 or the shoulder member 112, the clamping member 113 serves to surround their outer periphery. Because the clamping member 113 surrounds the material, preventing the friction stirring material from scattering, the friction stirring section can be smoothly completed.

[0047] A spring 114 is mounted on the upper end of the clamping member 113 and applies a downward force to the clamping member 113 in the direction of the mating object. The clamping member 113 is mounted to the tool fixing part by means of the spring 114.

[0048] The backing member 115 has an upper side that abuts against the lower side of the mating object and serves as a support surface. That is, the backing member 115 is a backing member that supports the mating object when the pin member 111 or the shoulder member 112 is pressed into the mating object. The clamping member 113, which is subjected to a force by the spring 114, presses the mating object against the backing member 115.

[0049] The tool drive unit 102 includes a rotation drive unit 121, a pin drive unit 122, a shoulder drive unit 123, and a clamping drive unit 124. The rotation drive unit 121 includes a motor and drive gears, driving the pin member 111 and the shoulder member 112 to rotate about a pivot axis R. The pin drive unit 122 is a mechanism that moves the pin member 111 forward and backward (lifts and lowers) along the pivot axis R. The pin drive unit 122 drives the pin member 111 to press it into and out of the mating object. The shoulder drive unit 123 is a mechanism that moves the shoulder member 112 forward and backward along the pivot axis R, causing the shoulder member 112 to press into and out of the mating object. The clamping drive unit 124 is a mechanism that moves the clamping member 113 forward and backward along the pivot axis R. The clamping drive unit 124 moves the clamping member 113 toward the mating object, pressing the mating object against the backing member 115. At this time, the spring 114 applies a force.

[0050] The controller C, equipped with a microcomputer, controls the operation of each part of the tool drive unit 102 by executing a specified control program. Specifically, the controller C controls the rotation drive unit 121 to cause the pin member 111 and the shoulder member 112 to perform the required rotational movements. Furthermore, the controller C controls the pin drive unit 122, the shoulder drive unit 123, and the clamping drive unit 124 to cause the pin member 111, the shoulder member 112, and the clamping member 113 to perform the required forward and backward movement movements.

[0051] Friction stir joining apparatus M with the structure described above is typically used to join two or more components by friction stir joining. Friction stir joining using this friction stir joining apparatus M can be broadly classified into joining methods based on shoulder-first process and joining methods based on pin-first process.

[0052] In the shoulder-first joining method, friction stirring is performed by first pressing the shoulder member 112 of the rotating tool 101 into the overlapping portion of two or more members, and then the pin member 111 is retracted from the overlapping portion. Subsequently, the upper surface of the overlapping portion is smoothed by simultaneously retracting (raising) the shoulder member 112 and lowering the pin member 111. In the pin-first joining method, friction stirring is performed by first pressing the pin member 111 of the rotating tool 101 into the overlapping portion, and then the shoulder member 112 is retracted from the overlapping portion. Subsequently, the upper surface of the overlapping portion is smoothed by simultaneously retracting (raising) the pin member 111 and lowering the shoulder member 112.

[0053] [Manufacturing of the joint structure]

[0054] Here, in this embodiment, when manufacturing the joint structure 1, not only is the conventional friction stir joint, i.e., the joint method based on shoulder-first process or pin-first process, used, but also a combination of rivets 40 ( Figure 2 The rivets are joined by friction stirring and rivet installation. The rivet-fed friction stirring joint differs from the conventional friction stirring joint in that a rivet is added as a joining means. In this embodiment, a shoulder-first process is applied, utilizing... Figure 4 The same friction stir joining device M shown can achieve rivet joining using friction stir joining. That is, the joining structure 1 of this embodiment is manufactured by combining rivet joining using friction stir joining with the same friction stir joining device M and conventional friction stir joining. For example, the joining structure 1 can be manufactured in a manner similar to the steps below.

[0055] First, the first member 11 and the second member 12 are configured such that the abutting surface 32a of the flange portion 32 of the second member 12 abuts against the back surface 22 of the first member 11.

[0056] Next, using the same friction stirring joining device M, multiple locations of the flange portion 32 are joined to the first member 11, forming multiple joint portions 13 along the flange portion 32. During this joining, depending on the joining position of the flange portion 32, rivet-assisted friction stirring joining and conventional friction stirring joining are used. Specifically, the front and rear ends of the flange portion 32 are joined to the first member 11 using rivet-assisted friction stirring joining, thereby forming a pair of front and rear end joint portions 13A, and multiple locations of the middle portion of the flange portion 32 are joined to the first member 11 using conventional friction stirring joining, thereby forming multiple, specifically three, intermediate joint portions 13B. Thus, a joined structure 1 is manufactured based on the flange portion 32 of the first member 11 and the second member 12 joined by multiple joint portions 13 including a pair of end joint portions 13A and multiple intermediate joint portions 13B. The formation of the end joint 13A based on the above-described rivet and friction stir joining corresponds to the end joining step in the present invention, and the formation of the intermediate joint 13B based on the above-described conventional friction stir joining corresponds to the intermediate joining step in the present invention.

[0057] The order in which the multiple joints 13 are formed can be set arbitrarily. For example, multiple intermediate joints 13B can be formed after a pair of end joints 13A are formed, or a pair of end joints 13A can be formed after a pair of intermediate joints 13B are formed.

[0058] [Method for forming the end joint]

[0059] Next, a method for forming the end joint 13A using the friction stirring joining device M will be described in detail. The end joint 13A is formed based on the rivet described above and by friction stirring joining. That is, the end joint 13A is formed by pressing the shoulder member 112 of the rotating tool 101 into the overlapping portion 15 of the flange portions 32 of the first member 11 and the second member 12 and performing friction stirring, and then driving the rivet 40 into the friction-stirred overlapping portion 15. In detail, the method for forming the end joint 13A includes the following four steps P11 to P15.

[0060] like Figure 5 As shown, step P11 is a preparation step for assembling the rivet 40 onto the rotating tool 101. In this preparation step P11, the rivet 40 assembled onto the rotating tool 101 is the rivet 40 before it is driven into the overlapping portion 15, and its shaft portion 42 has not yet been enlarged. That is, the rivet 40 used in preparation step P11 has a head 41 and a cylindrical shaft portion 42 extending linearly from the head 41. The inner circumferential surface of the shaft portion 42 is tapered so that the wall thickness decreases towards the distal end 42a, i.e., it becomes sharper towards the distal end.

[0061] In order to assemble rivet 40 onto rotating tool 101, controller C ( Figure 4 The drive pin drive unit 122 raises the pin member 111, thereby forming a receiving space H for the rivet 40 inside the shoulder member 112. Specifically, the controller C raises the distal end (lower end) 111a of the pin member 111 relative to the distal end (lower end) 112a of the shoulder member 112 by more than the full height of the rivet 40, thus forming a receiving space H connected to the lower end opening of the shoulder member 112. To allow the rivet 40 to be received in this receiving space H, a rivet 40 is selected with an outer diameter slightly smaller than the inner diameter of the shoulder member 112.

[0062] like Figure 6 As shown, step P12 is a positioning step in which the rotating tool 101 equipped with rivets 40 is positioned at the overlapping portion 15. In this positioning step P12, the controller C causes the rotating shaft R of the rotating tool 101 to rotate. Figure 4 After positioning the pin 111 in a manner aligned with the center of the overlapping portion 15 supported on the backrest member 115, the shoulder drive 123 and the clamping drive 124 are controlled so that the distal ends 112a and 113a of the shoulder member 112 and the clamping member 113 abut against the upper side of the second member 12 (flange portion 32). Furthermore, the controller C maintains the axial relative positional relationship between the pin member 111 and the shoulder member 112, causing the distal end 111a of the pin member 111 to retract above the distal end 112a of the shoulder member 112 by a specified amount, so that the rivet 40 is accommodated between the distal end 111a of the pin member 111 and the upper side of the second member 12 (flange portion 32).

[0063] like Figure 7 As shown, step P13 is the pressing step of pressing in the shoulder member 112. In this pressing step P13, the controller C controls the rotation drive 121 to rotate the pin member 111 and the shoulder member 112 at high speed, while controlling the shoulder drive 123 to lower the shoulder member 112, pressing the shoulder member 112 into the overlapping portion 15. Furthermore, the controller C controls the pin drive 122 to raise the pin member 111. Based on this action, the overlapping portion 15 is frictionally stirred, resulting in material softening and plastic flow, and the softened material Q1 overflows from the pressing area of ​​the shoulder member 112. The overflowing softened material Q1 is released, as shown by arrow b1, into the hollow space within the shoulder member 112 created by the rising (retraction) of the pin member 111. Furthermore, at the beginning of the pressing step P13, since the pin member 111 retracts to the already formed receiving space H (… Figure 5 Therefore, the retraction action of the pin component 111 can be omitted as it is above the level of ) .

[0064] When the pressing depth of the shoulder member 112 is h1, it is ideally set such that the shoulder member 112 penetrates the upper second member 12 but does not penetrate the lower first member 11. In other words, it is ideally set to a value greater than the thickness t2 of the flange portion 32 of the second member 12 and less than the sum of the thickness t2 and the thickness t1 of the first member 11 (t1+t2). In this case, the friction stirring part 50 formed in the subsequent setting steps P14 and P15 ( Figure 8A B) It penetrates the second member 12 (flange 32) in the thickness direction and reaches the middle of the thickness direction of the first member 11, that is, between the surface 21 and the back surface 22 of the first member 11.

[0065] In this embodiment, since the first component 11 and the second component 12 are thermoplastic composite materials, the material Q1 softened by the friction stirring contains reinforcing fibers. However, the reinforcing fibers in the softened material Q1 are shredded by the friction stirring. This makes the subsequent installation of the rivets 40 easier.

[0066] like Figure 8A As shown in Figures B and C, steps P14 and P15 are the steps of installing the rivet 40 into the overlapping portion 15. In these steps P14 and P15, the controller C controls the rotation drive unit 121 to rotate the pin member 111 and the shoulder member 112 at high speed, and controls the shoulder drive unit 123 to raise the shoulder member 112. Furthermore, after the shoulder member 112 rises, the controller C controls the pin drive unit 122 to lower the pin member 111. Based on this operation, a cylindrical friction stirring part 50 is formed in the overlapping portion 15, and the rivet 40 is installed in the area containing the friction stirring part 50. The formation of the friction stirring part 50 and the installation of the rivet 40 will be described in detail below.

[0067] First, the formation of the friction stirring section 50 based on the setting steps P14 and P15 will be explained. In the setting steps P14 and P15, based on the rising of the shoulder member 112 and the falling of the pin member 111, the softening material Q1 ( ) is released into the hollow space. Figure 7 The material moves towards the area pressed into the shoulder member 112 to backfill. The backfilled material, together with the material present in the hollow space, forms a friction stirring section 50 in the overlapping portion 15. The friction stirring section 50 is composed of the friction-stirred material in the overlapping portion 15 and is formed to have a diameter ds ( ) similar to the outer diameter ds of the shoulder member 112. Figure 8B The outer diameter is roughly the same as that of the shoulder member 112 and the insertion depth h1 is similar to that of the shoulder member 112. Figure 7The friction stirring section 50 is cylindrical with a roughly uniform height. That is, the friction stirring section 50 has a cylindrical side circumferential surface 50a with a height h1 and a circular bottom surface 50b with an outer diameter ds. On the one hand, the material softens in the friction stirring section 50, and on the other hand, the original hardness of the first component 11 and the second component 12 is maintained in the base material region around the friction stirring section 50, and the reinforced structure based on the reinforcing fiber is also maintained.

[0068] Next, the installation of the rivet 40 based on installation steps P14 and P15 will be explained. In installation steps P14 and P15, the rivet 40 is pressed downwards based on the descent of the pin member 111, and the pressed rivet 40 is pressed into the overlapping portion 15. In other words, in installation steps P14 and P15, the rivet 40 is installed using the existing member of the rotating tool 101, namely the pin member 111. Therefore, in this embodiment, without preparing a separate tool for installing the rivet 40, it is possible to form an end joint portion 13A including the rivet 40 and the friction stirring portion 50.

[0069] Specifically, in steps P14 and P15, such as Figure 8A As shown in Figure B, the pin drive unit 122 lowers the pin member 111 to apply pressure to the head 41 of the rivet 40, pressing the rivet 40 into the overlapping portion 15. The rivet 40 is pre-loaded into the receiving space H with the top surface of its head 41 facing the distal end 111a of the pin member 111. Figure 5 Therefore, when the pin member 111 descends, the rivet 40 also descends, and its shaft portion 42 enters the interior of the friction stirring section 50 from the distal end side. After this entry of the rivet 40, i.e., after the pin member 111 is pressed down, the distal end 42a of the shaft portion 42 soon reaches the bottom surface 50b of the friction stirring section 50. Here, since the area below the bottom surface 50b is an unsoftened base material area, the axial resistance acting on the shaft portion 42 increases after the distal end 42a reaches the bottom surface 50b. Therefore, with at least the distal end 42a reaching the bottom surface 50b, a force acts on the shaft portion 42 to expand its diameter. This expansion force is facilitated by the tapered shape applied to the inner circumferential surface of the distal end 42a. That is, the synergistic effect of the increased resistance generated by the distal end 42a reaching the bottom surface 50b and the tapered shape of the distal end 42a, such as... Figure 8B As shown, the shaft portion 42 of the rivet 40 is deformed into a bell shape, with the outer diameter increasing towards the distal end.

[0070] Figure 8BThis figure shows the state where the head 41 of the rivet 40 reaches the upper side of the overlapping portion 15, that is, the upper side of the flange portion 32 of the second member 12, which is the state where the rivet 40 is installed. As shown in the figure, when the rivet 40 is installed, the distal end 42a of its shaft portion 42 not only extends beyond the bottom surface 50b of the friction stirring portion 50 and is pressed into the base material area below it, but also extends beyond the side peripheral surface 50a of the friction stirring portion 50 and is pressed into the base material area outside it. The distal end 42a, which is pressed into the outside of the friction stirring portion 50, has an anchoring effect against the force that would separate the first member 11 and the second member 12. That is, the distal end 42a functions as an interlocking part that fixes the first member 11 and the second member 12 (flange portion 32).

[0071] Based on the above steps P11 to P15, a friction stirring part 50 is formed in the overlapping portion 15 and a rivet 40 is provided. The rivet 40 and the friction stirring part 50 constitute an end joint portion 13A that joins the flange portions 32 of the first member 11 and the second member 12 in the overlapping portion 15. That is, by forming an end joint portion 13A including the rivet 40 and the friction stirring part 50 in the overlapping portion 15, the flange portion 32 of the second member 12 is joined to the first member 11 at its end in the front-rear direction.

[0072] [Method for forming the intermediate joint]

[0073] Next, the method for forming the intermediate joint 13B using the friction stir joining apparatus M will be described in detail. The intermediate joint 13B is formed based on the conventional friction stir joining described above. Conventional friction stir joining includes shoulder-first and pin-first processes as described above, and the intermediate joint 13B can be formed using either method. However, in this embodiment, the case where the intermediate joint 13B is formed using the shoulder-first process will be described. In this case, the intermediate joint 13B is based on... Figure 9 The process is completed through the four steps P21 to P24 shown.

[0074] Step P21 is a positioning step in which the rotating tool 101 is positioned on the overlapping portion 16. In this positioning step P21, the controller C ( Figure 4 ) so that the rotating shaft R of the rotating tool 101 ( Figure 4 After positioning the pin member 111, shoulder member 112, and clamping member 113 at their respective distal ends 111a to 113a abut against the upper side of the flange portion 32 of the second member 12, the tool drive 102 is controlled to position the pin member 111, shoulder member 112, and clamping member 113 at their respective distal ends 111a to 113a abut against the upper side of the flange portion 32 of the second member 12.

[0075] Step P22 is the pressing-in step of the shoulder member 112. In this pressing-in step P22, the controller C controls the rotation drive unit 121 to rotate the pin member 111 and the shoulder member 112 at high speed, and controls the shoulder drive unit 123 to lower the shoulder member 112, pressing the shoulder member 112 into the overlapping portion 16. Furthermore, the controller C controls the pin drive unit 122 to raise the pin member 111. Based on this action, the overlapping portion 16 is frictionally agitated, resulting in material softening and plastic flow, and the softened material Q2 overflows from the pressing area of ​​the shoulder member 112. The overflowed softened material Q2 is released, as shown by arrow b2, into the hollow space within the shoulder member 112 created by the rising (retracting) of the pin member 111. The pressing depth h2 of the shoulder member 112 is set to a value such that the shoulder member 112 at least penetrates the upper second member 12. Furthermore, in Figure 9 The diagram shows an example where the shoulder member 112 is pressed into the middle of the thickness direction of the lower first member 11. In this case, the friction stirring part 51 formed in the leveling step P24 described later penetrates the second member 12 (flange 32) in the thickness direction and reaches the middle of the thickness direction of the first member 11.

[0076] Step P23 is the backfilling step, in which the overflowed softened material Q2 is backfilled. In this backfilling step P23, the controller C rotates the pin member 111 and the shoulder member 112 at high speed while controlling the shoulder drive unit 123 and the pin drive unit 122 to raise (retract) the shoulder member 112 and lower the pin member 111. Based on this action, as shown by arrow b3, the softened material Q2 released into the hollow space moves towards the area pressed into the shoulder member 112, and the material is backfilled. The backfilled material, as shown in the figure of the next step P24, together with the material present in the hollow space, forms a friction stirring part 51 in the overlapping part 16. The friction stirring part 51 is composed of the material that has been frictionally stirred in the overlapping part 16 and is formed into a cylinder with an outer diameter approximately the same as the outer diameter ds of the shoulder member 112 and a height approximately the same as the pressing depth h2 of the shoulder member 112. That is, the friction stirring part 51 has a cylindrical side circumferential surface 51a with a height h2 and a circular bottom surface 51b with an outer diameter ds.

[0077] Step P24 is a leveling step for smoothing the friction stirring section 51. In this leveling step P24, the controller C, with the distal ends 111a and 112a of the pin member 111 and the shoulder member 112 returned to the height position of the upper side of the flange portion 32 of the second member 12, drives the rotation drive unit 121 to rotate the pin member 111 and the shoulder member 112 at a specified speed. Based on this action, the upper surface of the friction stirring section 51 is shaped and smoothed to the point where there is almost no unevenness.

[0078] According to steps P21 to P24 above, a friction stirring section 51 with a smooth upper surface is formed in the overlapping portion 16. The friction stirring section 51 forms an intermediate joint portion 13B that joins the flange portions 32 of the first member 11 and the second member 12 in the overlapping portion 16. That is, by forming the intermediate joint portion 13B composed of the friction stirring section 51 in the overlapping portion 16, the flange portion 32 of the second member 12 is joined to the first member 11 at its midpoint in the front-rear direction. Since the intermediate joint portion 13B does not contain the aforementioned rivet 40, the joint strength of the intermediate joint portion 13B is lower than the joint strength of the end joint portion 13A that contains the rivet 40.

[0079] [Effects]

[0080] As described above, in the joint structure 1 of this embodiment, the flange portion 32 of the first member 11 and the second member 12 that abuts against the first member is joined based on a pair of end joint portions 13A and an intermediate joint portion 13B. The pair of end joint portions 13A include rivets 40 and friction stirring portions 50, and the intermediate joint portion 13B includes friction stirring portions 51 but does not include rivets 40. Therefore, it has the advantage of being able to manufacture a joint structure 1 with sufficient strength relatively inexpensively.

[0081] Since the joint obtained by fusing materials softened by friction stirring is a friction-stirring part, its joint strength (load resistance) is tends to be lower than that of a joint using rivets 40 as a mechanical joining method. In this embodiment, the end joint 13A includes both the friction stirring part 50 and rivets 40, therefore, the end joint 13A necessarily has high joint strength. In other words, in this embodiment, the joint strength of the end joint 13A, which includes both the friction stirring part 50 and rivets 40, is sufficiently higher than that of the intermediate joint 13B, which only includes the friction stirring part 51 and not rivets 40. Furthermore, the high-strength end joint 13A is applied to the end of the flange 32, which is prone to high stress under external forces such as bending or shearing. Therefore, it is possible to effectively suppress the breakage of the end joint 13A due to such external forces, and to sufficiently ensure the overall joint strength of the joint structure 1.

[0082] On the other hand, regarding the intermediate joint 13B located between the pair of end joints 13A, since it includes a friction stirring part 51 but does not include rivets 40, the rivets 40, which are auxiliary materials, can be omitted from the intermediate joint 13B. Therefore, since the required number of rivets 40 is reduced, the manufacturing cost of the joint structure 1 and the time required for its manufacture can be reduced. Furthermore, it has the advantage of being able to suppress the increase in weight of the joint structure 1 caused by adding rivets 40.

[0083] In particular, in this embodiment, when forming the end joint 13A, the existing pin member 111 of the friction stir joint device M is used to drive the rivet 40, so there is no need to prepare a special device for driving the rivet 40. As a result, the end joint 13A and the intermediate joint 13B can be formed using the same friction stir joint device M, which can effectively improve the manufacturing efficiency of the joint structure 1.

[0084] [Variation Example]

[0085] In the embodiment described above, when forming the end joint 13A and the intermediate joint 13B, the rotating tool 101 is pressed into the overlapping portion 15 and 16 of the first member 11 and the second member 12 (flange portion 32) from the side of the second member 12. However, the rotating tool 101 can also be pressed into the first member 11 from the opposite side.

[0086] In the described embodiment, the first member 11 and the second member 12 are stacked and joined in a mutually abutting state. However, it is also possible to further stack one or more other members on the first member 11 and the second member 12 and join these members in this state. That is, the joining structure of the present invention is only a structure formed by joining at least two members based on multiple joining parts, and the multiple joining parts include a pair of end joining parts and an intermediate joining part. It can be a structure formed by joining three or more members with multiple joining parts.

[0087] In the described embodiment, both the first component 11 and the second component 12 are formed of a thermoplastic composite material comprising a substrate made of thermoplastic resin and a plurality of reinforcing fibers impregnated in the substrate. However, the materials of the first component 11 and the second component 12 may also be different from each other. For example, one of the first component 11 and the second component 12 may be a molded body made of thermoplastic resin, while the other may be a molded body made of fiber-reinforced composite material. Alternatively, one of the first component 11 and the second component 12 may be a molded body made of metal, while the other may be a molded body made of a metal or a thermoplastic resin of a different nature.

[0088] In the described embodiment, three intermediate joints 13B are provided between a pair of end joints 13A, but the number of intermediate joints 13B can be appropriately varied depending on the length of the flange 32, etc. For example, the number of intermediate joints 13B can be one, two, or more than three.

[0089] In the embodiment described, the flange portions 32 of the first member 11 and the second member 12 are joined by a plurality of joint portions 13 arranged in a row in the front-back direction, but they can also be joined by joint portions arranged in multiple rows. Figure 10An example is shown in the figure. The joining structure 1A shown in the figure includes: a first member 11, the same as in the embodiment described above; and a second member 61 comprising a main body portion 62 and a relatively wide flange portion 63. The flange portion 63 is joined to the first member 11 based on a plurality of joining portions 13 arranged in two rows in the front-rear direction. Figure 10 In the case where the column of joints 13 arranged along line L1 is designated as the first column, and the column of joints 13 arranged along line L2 parallel to line L1 is designated as the second column, each of the first and second columns includes a pair of end joints 13A at the front and rear, and a plurality of, specifically, three, intermediate joints 13B located therebetween. Each end joint 13A includes a rivet 40 and a friction stirring part 50. Figure 2 Each intermediate joint 13B contains only a friction stirring part 51. Figure 3 However, this hybrid structure of two types of joints—that is, a structure combining an end joint 13A containing rivets 40 and an intermediate joint 13B without rivets 40—does not need to be applied to both the first and second columns. The hybrid structure only needs to be applied to at least one of the columns. For example, if the hybrid structure applies only to one of the first and second columns, the joints 13 of the other column can all be configured with the same structure as the intermediate joint 13B without rivets 40. This also applies to columns with three or more joints.

[0090] exist Figure 10 In the joining structure 1A, the joining portions 13 are arranged in multiple columns within the relatively wide flange portion 63, but this can also be replaced by... Figure 11 As shown in the joint structure 1B, the joint portions 13 are arranged in a serrated manner. In this case, the joint portion 13 located at the foremost or rearmost side of the flange portion 63 is set as the end joint portion 13A containing the rivet 40 and the friction stirring portion 50, and the remaining joint portions 13 are set as the intermediate joint portions 13B containing the friction stirring portion 51.

[0091] In the described embodiment, an example of applying the present invention to a joint structure 1 formed by joining a first flat plate member 11 and a second member 12 with an L-shaped cross section is illustrated. However, the present invention is not limited to the example of the above embodiment and can be widely applied to joint structures formed by joining two or more members.

[0092] For example, the present invention can be applied to Figure 12 The shown joint structure 1C. Figure 12The joining structure 1C includes a first member 11 in the shape of a deck, similar to that in the described embodiment, and a second member 71 formed in the shape of a cap in cross-section. The second member 71 is a skeleton member, having a main body 72 extending in the front-rear direction with an inverted U-shaped cross-section and a pair of flanges 73 provided from the two sides of the main body 72 in a manner extending to the left and right, respectively. Each flange 73 has an independent abutment surface 73a on its side of the first member 11. Each flange 73 is joined to the first member 11 by a plurality of joining portions 13 arranged in the front-rear direction. In such a joining structure 1C, the same joining structure as in the described embodiment is applied to at least one of the flanges 73. Figure 12 In the case of the right-side flange portion 3, at least one flange portion 73 is provided with a pair of front and rear end joint portions 13A and a plurality of, specifically three, intermediate joint portions 13B located between them. Each end joint portion 13A includes a rivet 40 and a friction stirring portion 50. Figure 2 Each intermediate joint 13B contains only a friction stirring part 51. Figure 3 Furthermore, regarding the flange 73 on the other side, that is... Figure 12 There are no special requirements for the joining structure of the flange portion 73 on the left side. It can also be configured to have a structure that combines the end joining portion 13A and the intermediate joining portion 13B, just like the flange portion 73 on the other side.

[0093] As another variation, the invention can also be applied to a joint structure formed by joining a Z-shaped skeletal member to a plate-shaped first member. Thus, the invention is well-suited for joint structures formed by joining a plate-shaped member (first member) and a non-plate-shaped skeletal member (second member) joined to that member.

[0094] In the described embodiment, a friction stirring section 50 is formed at the end joint 13A, extending through the second member 12 (flange 32) in the thickness direction and reaching the middle of the first member 11 in the thickness direction. However, the depth of the friction stirring section 50 can be varied in various ways. For example, a friction stirring section may be formed at the end joint 13A that just penetrates the second member 12 but does not reach the first member 11. Furthermore, it may be as follows... Figure 13 As shown, a friction stirring section 50' that does not penetrate the second member 12 is formed at the end joint 13A; in other words, a friction stirring section 50' is formed in the middle of the thickness direction of the second member 12.

[0095] In the described embodiment, the foremost or rearmost joint 13 in the flange 32 is designated as an end joint 13A containing a rivet 40 and a friction stirring part 50, while the remaining joints are designated as intermediate joints 13B containing only the friction stirring part 51 and omitting the rivet 40. However, it is permissible as long as the end joint 13A contains at least a rivet, and as long as the intermediate joint 13B contains at least a friction stirring part. For example, the end joints can be designed to contain only a rivet, meaning the friction stirring part can be omitted from the end joints. Furthermore, various modifications can be made to the intermediate joints as long as their joint strength is lower than that of the end joints and they contain a friction stirring part.

[0096] [Summarize]

[0097] The above-described embodiments and their variations mainly include the following inventions.

[0098] One aspect of the present invention relates to a joining structure comprising: a first member; a second member including an opposing portion facing the first member in the thickness direction; and a plurality of joining portions for joining the first member and the second member and disposed along the opposing portion; wherein the plurality of joining portions includes: a pair of end joining portions located at both ends of the opposing portion; and an intermediate joining portion located between the pair of end joining portions and having a joining strength lower than that of the end joining portions; wherein the end joining portions include a fastener for mechanically joining the first member and the second member, and the intermediate joining portion includes a friction stirring portion for joining the first member and the second member by friction stirring.

[0099] Since the joint obtained by fusing materials softened by friction stirring is a friction-stirring joint, its joint strength (load resistance) tends to be lower than that of a joint using a solid as a mechanical joining method. This means that the joint strength of the end joint containing the solid can be significantly higher than that of the intermediate joint containing the friction stirring joint. Moreover, the end joint with high joint strength is applicable to the ends of opposing parts that are prone to high stress under external forces such as bending or shearing. Therefore, it is possible to effectively suppress the breakage of the end joint due to such external forces, and to ensure sufficient joint strength of the joint structure as a whole.

[0100] On the other hand, the intermediate joint located between a pair of end joints can be any structure that includes a friction stirring section, and the fasteners used as auxiliary materials can be omitted from the intermediate joint. Therefore, since the required number of fasteners is reduced, the manufacturing cost and time required for the joint structure can be reduced. Furthermore, it has the advantage of suppressing the increase in weight of the joint structure due to the addition of fasteners.

[0101] Ideally, the end joint includes, in addition to the fastener, a friction stirring part that joins the first component and the second component by friction stirring, while the intermediate joint includes the friction stirring part but does not include the fastener.

[0102] According to this configuration, the joint strength of the end joint that combines the solid and the friction stirring part can be made to be sufficiently higher than the joint strength of the intermediate joint that only contains the friction stirring part.

[0103] The friction stirring section can be configured, for example, to extend through the second member in the thickness direction and reach the middle of the thickness direction of the first member.

[0104] According to this configuration, the first component and the second component can be properly joined by the friction stirring part.

[0105] The second component may comprise two or more independent opposing portions. In this case, the pair of end joints and the intermediate joint are applied to at least one of the opposing portions.

[0106] The materials of the first component and the second component are not particularly limited. As a preferred example, the first component and the second component are formed of thermoplastic resin or thermoplastic composite material obtained by impregnating reinforcing fibers in thermoplastic resin.

[0107] According to this configuration, components made of thermoplastic resin or thermoplastic composite material can be joined together with the desired strength and their manufacturing costs can be suppressed.

[0108] The shape and purpose of the first component and the second component are not particularly limited. As a preferred example, the first component is a plate-shaped component that constitutes the outer plate of the structure, and the second component is a non-flat skeleton component that extends along the back of the first component in a specific direction.

[0109] According to this configuration, it is possible to join sheet metal and rib components with the desired strength and to suppress their manufacturing costs, etc.

[0110] Another aspect of the present invention relates to a joining method for joining a first member and a second member comprising opposing portions facing the first member in the thickness direction, comprising: an end joining step of forming a pair of end joining portions located at both ends of the opposing portions; and an intermediate joining step of forming an intermediate joining portion between the pair of end joining portions with a joining strength lower than that of the end joining portions; wherein, in the end joining step, a joining portion comprising a fastener and a friction stirring portion is formed as the end joining portion, the fastener mechanically joining the first member and the second member, and the friction stirring portion joining the first member and the second member by friction stirring; in the intermediate joining step, a joining portion comprising a friction stirring portion but not a fastener is formed as the intermediate joining portion, the friction stirring portion joining the first member and the second member by friction stirring; the end joining step and the intermediate joining step are performed using the same friction stirring joining device.

[0111] According to the present invention, since no special device for fastening solids is required, the same friction joint device can be used to form the end joint and the intermediate joint, thereby effectively improving the manufacturing efficiency of the joint structure.

Claims

1. A joining structure, characterized in that... include: Component 1; The second component includes an opposing portion that faces the first component in the thickness direction; as well as, Multiple joints are provided along the opposing portions for joining the first member and the second member; wherein, The plurality of joints include: A pair of end joints, located at both ends of the opposing portions; and, An intermediate joint is located between the pair of end joints and has a lower joint strength than the end joints; wherein... The end joint includes a fastener that mechanically joins the first component and the second component. The intermediate joint includes a friction stirring section that joins the first component and the second component by friction stirring. In addition to the fastener, the end joint also includes a friction stirring part that joins the first component and the second component by friction stirring. The intermediate joint includes the friction stirring part but does not include a solid part. At the end joint, the fastener is applied to the region containing the friction stirring section.

2. The joining structure according to claim 1, characterized in that, The friction stirring section is formed to penetrate the second member in the thickness direction and reach the middle of the thickness direction of the first member.

3. The joining structure according to claim 1 or 2, characterized in that, The second component comprises two or more independent opposing portions. The pair of end joints and the intermediate joint are applied to at least one of the opposing parts.

4. The joint structure according to any one of claims 1 to 3, characterized in that, The first component and the second component are formed of thermoplastic resin or thermoplastic composite material obtained by impregnating reinforcing fibers in thermoplastic resin.

5. The joint structure according to any one of claims 1 to 4, characterized in that, The first component is a plate-shaped component that constitutes the outer panel of the structure. The second component is a non-flat skeletal component that extends in a specific direction along the back of the first component.

6. A joining method for joining a first member and a second member including opposing portions facing the first member in the thickness direction, characterized in that... include: The end-joining step forms a pair of end-joining portions located at both ends of the opposing portions; and In the intermediate joining step, an intermediate joining portion with a lower joining strength than the end joining portions is formed between the pair of end joining portions; wherein... In the end-joining step, a joint comprising a fastener and a friction stirring part is formed as the end-joining portion. The fastener mechanically joins the first component and the second component, and the friction stirring part joins the first component and the second component by friction stirring. The fastener is applied to the region containing the friction stirring part. In the intermediate joining step, a joint portion comprising a friction stirring section but not a solid is formed as the intermediate joining portion. The friction stirring section joins the first component and the second component through friction stirring. The end-joining step and the intermediate-joining step are performed using the same friction stirring joint device.

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