Jig for friction stir welding

Abstract

To provide a jig for friction stir joining inserted into inside of a hollow member in friction stir joining which is easily inserted and hardly causes deformation of the hollow member at the time of joining.SOLUTION: A jig can be inserted into inside of a hollow member to join the hollow member by friction stir joining. The jig can be variable in size in a pressure-reception direction where the hollow member is pressed by a tool of the friction stir joining.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a jig used when performing friction stir welding.

Background Art

[0002] When joining a hollow member by friction stir welding, it is known to use a jig such as that disclosed in Patent Document 1. When inserting such a jig inside the hollow member, if there is a gap between the jig and the inner surface of the hollow member, the hollow member will be pushed by the friction stir welding tool and deformed until it contacts the jig.

[0003] Patent Documents 2 and 3 disclose so-called mandrels, but neither is used for friction stir welding.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a jig for friction stir welding that is inserted inside a hollow member during friction stir welding of the hollow member, is easy to insert during insertion, and is unlikely to cause deformation of the hollow member during joining.

Means for Solving the Problems

[0006] This application discloses a jig that can be inserted inside a hollow member for joining the hollow member by friction stir welding, and which is capable of changing its dimensions in the pressure-receiving direction, which is the direction in which the hollow member is pressed by the friction stir welding tool.

[0007] The jig may have a cam member, and the dimension in the pressure-receiving direction may change as the cam member rotates.

[0008] The jig may be configured to include multiple members having inclined surfaces, and by pressing the multiple members against each other, the multiple members may slide and move relative to each other on the inclined surfaces, causing a change in the dimension in the direction of pressure.

[0009] The jig may be equipped with an elastic body, and the dimensions in the pressure-receiving direction may change when the elastic body is pressed.

[0010] The jig may have a component formed by connecting multiple links that are rotatable relative to each other, and may be configured such that when a force is applied in the direction in which the component extends, the links rotate relative to each other, causing a change in the dimension in the direction of pressure reception. In this case, each of the multiple links may be provided with a projection, and the projections may be configured to protrude in a direction perpendicular to the direction in which the member extends. [Effects of the Invention]

[0011] According to this disclosure, when inserting the jig into and withdrawing it from the hollow member, a large gap can be created between the jig and the inner surface of the hollow member. On the other hand, during friction stir welding (pressing and moving the tool), the jig and the inner surface of the hollow member can be brought into contact while suppressing deformation of the hollow member. Thus, a friction stir welding jig can be made that is easy to insert and less likely to cause deformation of the hollow member during welding. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 illustrates friction stir welding and jigs. [Figure 2]Figure 2 is a diagram illustrating the jig 10 for embodiment 1. [Figure 3] Figure 3 illustrates the jig 20 for embodiment 2. [Figure 4] Figure 4 is a diagram illustrating the jig 30 for embodiment 3. [Figure 5] Figure 5 is a diagram illustrating the jig 40 for embodiment 4. [Modes for carrying out the invention]

[0013] 1. Friction stir welding Friction stir welding itself is known in this disclosure. Specifically, as schematically shown in Figure 1, the cylindrical tool 1 has a projection called a probe 1a on its tip surface, and the tool 1 is rotated (R) while the probe 1a is inserted to a predetermined depth into the butt joint (unjoined portion) of the materials to be joined 2, and the tool 1 is moved (T) along the butt joint to perform the joining. This is because, as the tool 1 rotates, the material 2 to be joined around where the tool 1 is inserted is heated by frictional heat with the tool 1 and processing heat, causing the portion of the material 2 to soften and plastically flow around the joining area, mixing them together and forming a single unit.

[0014] This disclosure relates to a jig used when friction stir welding is performed on a butt joint, particularly when the material to be joined 2 is a hollow member 2 in the shape of a rectangular tube (tubular shape) having a butt joint, as schematically shown in Figure 1. The jig is inserted inside the hollow member 2 and supports the hollow member 2 from the inside. The jigs for each embodiment will be described below.

[0015] 2. Jig The following describes the jigs. The jigs of this disclosure are all characterized in that, when inserted inside the hollow member 2, they can change their dimensions in the direction connecting the surface of the hollow member 2 having abutting portion and the surface opposite it (this is the direction in which the tool 1 presses against the hollow member 2, and since the jig receives this pressing force, it is referred to as the "pressure receiving direction"). According to the jig of the present disclosure, when inserting the jig before joining and pulling out the jig after joining, by making the dimension in the pressure-receiving direction smaller, the insertion and extraction of the jig into the hollow member 2 can be facilitated. On the other hand, after inserting the jig inside the hollow member 2, the dimension of the jig in the pressure-receiving direction is changed to be larger, the jig is brought into contact with the inner surface of the hollow member 2, or the gap between the jig and the inner surface of the hollow member 2 is reduced. Thereby, even when the hollow member 2 receives a pressing force from the tool 1 during joining, the jig receives this force and supports the hollow member 2 before the hollow member 2 is greatly deformed, suppressing the deformation of the hollow member 2. Hereinafter, the jig will be described with more specific embodiments.

[0016] 2.1. Embodiment 1 FIG. 2 shows a diagram for explaining a jig 10 according to Embodiment 1. FIG. 2(a) is a perspective view showing a part of the jig 10, FIG. 2(b) is a view of the jig 10 from the side where the direction in which the jig 10 is inserted into the hollow member 2 is the depth / front-back direction of the paper surface, and the dimension of the jig 10 in the pressure-receiving direction is reduced. FIG. 2(c) represents a scene where the dimension of the jig 10 in the pressure-receiving direction is deformed to be larger from the same viewpoint as FIG. 2(b). As can be seen from these figures, the jig 10 has a first pressure-receiving member 11, a second pressure-receiving member 12, and a cam member 13.

[0017] The first pressure-receiving member 11 and the second pressure-receiving member 12 are plate-shaped members, and the two pressure-receiving members 11 and 12 are arranged side by side in the pressure-receiving direction so as to have opposing surfaces 11a and 12a whose plate surfaces face each other. Among the surfaces of the two pressure-receiving members 11 and 12, the surfaces on the opposite side of the opposing surfaces 11a and 12a are respectively directed so as to face the inner surface of the hollow member 2 and function as pressure-receiving surfaces 11b and 12b. One of the inner surfaces of the hollow member 2 (in this embodiment, the surface of the hollow member 2 facing the pressure-receiving surface 11b) has a butting portion to be joined by friction stir welding. In this embodiment, grooves 11c and 12c are provided on the opposing surfaces 11a and 12a of the first pressure-receiving member 11 and the second pressure-receiving member 12, and the cam member 13 is arranged here. Moreover, it is preferable that the first pressure receiving member 11 and the second pressure receiving member 12 are biased by a biasing member such as a spring (not shown) so as to attract each other in the pressure receiving direction. Thereby, when the dimension in the pressure receiving direction is reduced, the deformation becomes smooth. The materials of the first pressure receiving member 11 and the second pressure receiving member 12 are not particularly limited, and examples include metals and resins. Examples of the metal include alloys such as stainless steel, and examples of the resin include engineering plastics.

[0018] As can be seen from the comparison between FIGS. 2(b) and 2(c), the cam member 13 is a member whose distance in the pressure receiving direction changes due to its rotation. In this embodiment, the cam member 13 has a rod shape with an elliptical cross section, and a shaft member (not shown) is connected to its axis, and it can rotate around the axis due to the rotation of the shaft member. The specific shape of the cam member 13 is not limited to this, and it is sufficient that the distance in the pressure receiving direction can change due to its rotation. Instead of a rod shape, a plurality of short block-shaped cam members may be arranged at predetermined intervals along a shaft (not shown).

[0019] Such a cam member 13 is disposed between the opposing surface 11a of the first pressure receiving member 11 and the opposing surface 12a of the second pressure receiving member 12, and in this embodiment, it is disposed so as to pass through the grooves 11c and 12c. Thereby, by rotating the cam member 13 around its axis, it is possible to repeatedly switch between a posture in which the dimension in the pressure receiving direction becomes smaller as shown in FIG. 2(b) and a posture in which the dimension in the pressure receiving direction becomes larger as shown in FIG. 2(c).

[0020] 2.2. Embodiment 2 FIG. 3 shows a diagram for explaining the jig 20 according to Embodiment 2. FIG. 3(a) is a cross-sectional view along the extending direction of the jig 20 in a scene where the dimension in the pressure receiving direction is reduced, FIG. 3(b) is a perspective view of one pressure receiving member 23 provided in the jig 20, and FIG. 3(c) represents a scene where the jig 20 is deformed so that the dimension in the pressure receiving direction becomes larger from the same viewpoint as FIG. 3(a). Here, the "extending direction" is the direction in which the jig 20 is inserted into the hollow member 2, as indicated by the arrow in FIGS. 1 and 3. In FIG. 3, for the sake of clarity, the notation of repeated reference numerals is partially omitted. As can be seen from these figures, the jig 20 has a bolt 21, a nut 22, and a plurality of pressure-receiving members 23.

[0021] The bolt 21 is a known bolt, but in this embodiment, the bolt 21 has a head 21a and a shaft portion 21b in which a helical groove is formed, and the shaft portion 21b extends long in the direction of extension. The nut 22 is a nut that is screwed onto the shaft portion 21b of the bolt 21.

[0022] In this embodiment, the pressure-receiving member 23 is block-shaped and, as can be seen in Figure 3(b), is a columnar member having a trapezoidal cross-section. The pressure-receiving member 23 uses the surface formed by the long lower base of the trapezoid as the pressure-receiving surface 23a, and this surface contacts or approaches the inner surface (the surface having the abutting portion) of the hollow member 2 to support the hollow member 2. Furthermore, the inclined surface 23b formed by the trapezoidal legs of the pressure-receiving member 23 is provided with a hole 23c that penetrates across the two inclined surfaces 23b. This hole 23c is a so-called elongated hole, having a long shape in the pressure-receiving direction. The size of the hole 23c is such that the shaft portion 21b of the bolt 21 can pass through, but the head 21a of the bolt 21 and the nut 22 cannot fit through. The inclination angle of the inclined surface 23b is not particularly limited, as long as the pressure-receiving member 23 can move in the pressure-receiving direction, as will be explained next.

[0023] In the jig 20, a nut 22 is screwed onto the shaft portion 21b of a bolt 21, and multiple pressure-receiving members 23 are positioned between the head 21a of the bolt 21 and the nut 22. The multiple pressure-receiving members 23 are arranged in a line along the direction in which the shaft portion 21b of the bolt 21 extends, with the shaft portion 21b passing through the holes 23c of the pressure-receiving members 23. At this time, adjacent pressure-receiving members 23 are arranged so that the surfaces of the inclined surfaces 23b can overlap. Therefore, the pressure-receiving surfaces 23a of adjacent pressure-receiving members 23 are arranged alternately so that they are on opposite sides in the direction of pressure.

[0024] Such a jig 20 operates as follows: As shown in Figure 3(a), in the position where the dimension in the pressure-receiving direction is small, the head 21a of the bolt 21 and the nut 22 are separated by a predetermined distance, and in this case, the inclined surfaces 23b of adjacent pressure-receiving members 23 are separated, or even if they are in contact, they do not press strongly against each other. Next, as shown in Figure 3(c), the nut 22 and the head 21a of the bolt 21 are rotated in opposite directions relative to each other, bringing them closer together. As a result, the pressure receiving member 23 positioned between the nut 22 and the head 21a of the bolt 21 is pushed in the axial direction of the shaft portion 21b, causing adjacent inclined surfaces 23b to overlap and even press against each other. Then, the inclined surfaces 23b act as wedges, causing the pressure receiving surface 23a of each pressure receiving member 23 to move so that it protrudes in the pressure receiving direction. This increases the dimension of the jig 20 in the pressure receiving direction, and the pressure receiving surface 23a comes into contact with or approaches the inner surface (the surface with the abutting portion) of the hollow member 2, allowing the hollow member 2 to be supported from the inside during friction stir welding. After joining, the distance between the head 21a of the bolt 21 and the nut 22 is increased, in the opposite direction to the above, returning to the state shown in Figure 3(a). As described above, the jig 20 can switch between a position in which the dimension in the pressure-receiving direction is reduced, as shown in Figure 3(a), and a position in which the dimension in the pressure-receiving direction is increased, as shown in Figure 3(c).

[0025] 2.3.Form 3 Figure 4 shows a diagram illustrating the jig 30 in form 3. Figure 4(a) is a cross-sectional view of the jig 30 along its extension direction, showing a situation where the dimension in the pressure-receiving direction is reduced, while Figure 4(b) shows a situation where the jig 30 is deformed from the same viewpoint as Figure 4(a) so that the dimension in the pressure-receiving direction is increased. Here, "extension direction" is the direction in which the jig 30 is inserted into the hollow member 2, as indicated by the arrows in Figures 1 and 4. As can be seen from these figures, the jig 30 has a bolt 21, a nut 22, an end plate 31, and a pressure receiving member 32. Here, the bolt 21 and nut 22 can be considered the same as the bolt 21 and nut 22 of the jig 20 in the above-described form 2, so they are given the same reference numerals and their explanation is omitted.

[0026] The end plate 31 is a plate-shaped member and has a hole through which the shaft portion 21b of the bolt 21 passes in the direction of its plate thickness. In this embodiment, two end plates 31 are arranged. One end plate 31 is positioned so that the shaft portion 21b of the bolt 21 passes through the hole, and one of its plate surfaces is in contact with the head portion 21a of the bolt 21. The other end plate 31 is positioned so that the shaft portion 21b of the bolt 21 passes through the hole, and one of its plate surfaces is in contact with the nut 22. The two end plates 31 are arranged so that the surfaces that are not in contact with the head portion 21a of the bolt 21 or the nut 22 face each other.

[0027] In this embodiment, the pressure-receiving member 32 is composed of a cylindrical elastic body. Examples of materials that make up the elastic body include rubber and elastomer.

[0028] In the jig 30, a nut 22 is screwed onto the shaft portion 21b of the bolt 21, and end plates 31 are positioned on the head 21a of the bolt 21 and the nut 22 as described above. A pressure receiving member 32 is positioned between the two opposing end plates 31. The pressure receiving member 32 is cylindrical, and is positioned so that it extends in the direction in which the shaft portion 21b of the bolt 21 extends as the shaft portion 21b of the bolt passes through the cylindrical part of the pressure receiving member 32.

[0029] Such a jig 30 operates as follows: As shown in Figure 4(a), in the position where the dimension in the pressure-receiving direction is small, the head 21a of the bolt 21 and the nut 22 are separated by a predetermined distance, and the end plate 31 is similarly separated. Next, as shown in Figure 4(b), the nut 22 and the head 21a of the bolt 21 are rotated in opposite directions relative to each other, bringing them closer together. This also reduces the distance between the two end plates 31, causing the end plates 31 to press the elastic pressure-receiving member 32 in the axial direction (extending direction). As a result, the elastic pressure-receiving member 32 deforms to expand in the pressure-receiving direction, increasing its dimension in that direction. This causes at least a portion of the outer surface of the pressure-receiving member 32 to contact or approach the inner surface (the surface with the abutting portion) of the hollow member 2, allowing the hollow member 2 to be supported from the inside during friction stir welding. After joining, the state shown in Figure 4(a) is returned by increasing the distance between the head 21a of the bolt 21 and the nut 22, the opposite of the above. As described above, the jig 30 can switch between a position in which the dimension in the pressure-receiving direction is reduced, as shown in Figure 4(a), and a position in which the dimension in the pressure-receiving direction is increased, as shown in Figure 4(b).

[0030] 2.4.Form 4 Figure 5 shows a diagram illustrating the jig 40 for form 4. For clarity, the hollow member 2 is also shown in Figure 5, and the cross-section is shown so that the inside of the hollow member 2 is visible. Figure 5(a) is a view along the extension direction of the jig 40, showing a situation where the dimension in the pressure-receiving direction is reduced. Figure 5(b) is a magnified view of a part of the multiple pressure-receiving members 41 arranged inside the hollow member 2 in Figure 5(a). Figure 5(c) shows a situation where the jig 40 is deformed from the same viewpoint as Figure 5(b) so that the dimension in the pressure-receiving direction is increased. Here, "extension direction" is the direction in which the jig 40 is inserted into the hollow member 2, as indicated by the arrows in Figures 1 and 5. Note that some repetitive symbols have been omitted for clarity. As can be seen from these figures, the jig 40 includes a pressure receiving member 41, a stopper 42, a sprocket 43, and a winding machine 44.

[0031] In this embodiment, a so-called chain used for power transmission is formed by connecting multiple pressure-receiving members 41, and this is arranged inside the hollow member 2. Accordingly, multiple inner links 41a and outer links 41b, which act as pressure-receiving members 41, are connected alternately, and each link, which is connected in a repeating manner, is rotatably connected to one another, forming a single unit as a whole.

[0032] In this embodiment, the inner link 41a is provided with a projection 41c. The projection 41c is a projection that protrudes toward the surface of the inner surface of the hollow member 2 that is opposite to the surface where the abutting portion exists (the downward surface in Figure 5). That is, the projection 41c is provided on every other link in the arrangement and protrudes in a direction perpendicular to the direction in which the chain extends when it is in a straight line. Furthermore, the projection 41c is positioned at a location offset in one direction from the longitudinal center (the direction in which multiple links are connected) of one of the inner links 41a (in this embodiment, the position where it connects to one of the outer links 41b). As can be seen from Figures 5(a) and 5(b), when the pressure-receiving member 41 is decreasing in size in the pressure-receiving direction, the projection 41c contacts the inner surface of the hollow member 2, preventing the links 41a and 41b from becoming perfectly aligned. This allows for a more reliable and smoother deformation of the pressure-receiving member 41 to increase its size in the pressure-receiving direction, as will be described later.

[0033] The stopper 42 is a plate or block-shaped member, placed in the opening on the end face of the hollow member 2, and closing at least a portion of the opening. This receives and supports the tip of the pressure-receiving member 41.

[0034] As shown in Figure 5(a), the sprocket 43 is a pair of disc-shaped plates with blades on its outer circumference that can engage with the pressure-receiving member 41, which is a chain. By positioning the pressure-receiving member 41 between the pair of sprockets 42 and rotating it as indicated by arrow K in Figure 5(a), a force can be applied to the pressure-receiving member 41 so that it is moved inward into the hollow member 2 as indicated by arrow L. For this reason, the sprocket 43 is positioned on the end of the hollow member 2 opposite to the end where the stopper 42 is located.

[0035] The winding machine 44 is a roll-shaped component, and the end of the chain, which is made up of multiple pressure-receiving members 41, is connected to the end opposite to the end on the stopper 42 side. As a result, by rotating the winding machine 44 as shown by M in Figure 5(a), the chain (pressure-receiving members 41) is wound up, and the pressure-receiving members 41 can be moved in the opposite direction to the direction in which the sprocket 43 feeds the pressure-receiving members 41 (opposite to arrow L).

[0036] Such a jig 40 operates as follows: As shown in Figures 5(a) and 5(b), in the position where the dimension in the pressure-receiving direction is small, the multiple pressure-receiving members 41 are in a nearly straight line. However, as described above, they are not in a straight line due to the protrusions 41c. Next, when the sprocket 43 is rotated as shown by arrow K in Figure 5(a), each pressure-receiving member 41 is subjected to a force that moves it in the direction of arrow L and moves. However, since the chain, which is the linking body of the pressure-receiving members 41, has its end supported by stopper 42, its movement in the extending direction is restricted. As a result, the links rotate relative to each other at their joints and deform so that their dimension in the pressure-receiving direction increases, as shown in Figure 5(c). In this embodiment, the projection 41c prevents the multiple pressure-receiving members 41 from aligning in a straight line, so that the rotation at the joints is performed smoothly in the intended direction. As a result, the pressure-receiving member 41 can contact or approach the inner surface (the surface having the abutting portion) of the hollow member 2, thereby supporting the hollow member 2 from the inside during friction stir welding. On the other hand, after joining, the winding machine 44 is rotated in the direction indicated by arrow M (at this time the sprocket 43 is in a state where it can rotate freely), returning from the position in Figure 5(c) to the positions in Figures 5(a) and 5(b). As described above, the jig 40 can switch between a position in which the dimension in the pressure-receiving direction is reduced, as shown in Figures 5(a) and 5(b), and a position in which the dimension in the pressure-receiving direction is increased, as shown in Figure 5(c). [Explanation of Symbols]

[0037] 1...Tool, 2...Hollow member, 10...Jig, 11...First pressure receiving member, 12...Second pressure receiving member, 13...Cam member, 20...Jig, 21...Bolt, 22...Nut, 23...Pressure receiving member, 30...Jig, 31...End plate, 32...Pressure receiving member, 40...Jig, 41...Pressure receiving member, 42...Stopper, 43...Sprocket, 44...Winding machine

Claims

1. A jig that can be inserted inside a hollow member for joining the hollow member by friction stir welding, The dimensions of the hollow member can be changed in the pressure-receiving direction, which is the direction in which it is pressed by the friction stir welding tool. The jig comprises an elastic body, and by pressing the elastic body, the dimension in the pressure-receiving direction changes. jig.

2. A jig that can be inserted inside a hollow member for joining the hollow member by friction stir welding, The dimensions of the hollow member can be changed in the pressure-receiving direction, which is the direction in which it is pressed by the friction stir welding tool. The jig has a member formed by connecting a plurality of links that are rotatable relative to each other, and when a force is applied in the direction in which the member extends, the links rotate relative to each other and the dimension in the pressure-receiving direction changes. jig.

3. The jig according to claim 2, wherein every other link is provided with a projection, and the projections protrude in a direction perpendicular to the direction in which the member extends.

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