Guide block and friction stir welding method

Abstract

To provide a guide block and a friction stirring and joining method which can press a pair of joined members forming an inner corner part even when the surfaces of the joined members are curved surfaces. and can suppress floating and vibration.SOLUTION: A guide block 20 has a guide hole 22 rotatably holding a stirring pin 11, and a pair of guide rollers 24 arranged across the guide hole 22, wherein the guide roller 24 is formed in a spherical shape, and can be rotated to each surface (an end face 7, a surface 8) of a pair of joined members (a cylindrical body 5, a joint 6) forming an inner corner part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a guide block for inner corner friction stir welding and a friction stir welding method. [Background technology]

[0002] When performing friction stir welding on a pair of workpieces that form an inner corner, a rotary tool for inner corner welding is used, in which a triangular prism-shaped base block is attached to a stirring pin (Patent Document 1). The base block rotatably holds and guides the stirring pin, and the pair of inclined surfaces abut against the surfaces of the pair of members, thereby pressing down on the members to be joined and preventing them from lifting up or vibrating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-79031 Summary of the Invention [Problem to be solved by the invention]

[0004] The rotary tool for joining inner corners in Patent Document 1 described above has a pair of inclined surfaces formed on the base block that are flat. If the surfaces of the pair of components to be joined are flat, the surfaces will come into surface contact with each other, thereby pressing down on the components to be joined and preventing them from lifting up or vibrating. However, if even one of the surfaces of a pair of members to be joined is not flat, line contact or point contact will occur, and it may not be possible to hold down the members to prevent them from lifting up or vibrating.

[0005] For example, when joining a cylindrical joint to the inside of the end of a cylindrical body, the end face of the outer cylinder is flat, while the surface of the inner joint is cylindrical. When performing friction stir welding on an inner corner of a ring-shaped joint formed by such a flat and cylindrical surface, if a rotary tool for joining inner corners with a pair of flat inclined surfaces is used, the flat inclined surfaces will not be able to make surface contact with the cylindrical joint surface, but will instead make line contact. As a result, the base block becomes unstable and can rotate around this contact line, making it impossible to hold down the workpieces to prevent lifting or vibration.

[0006] An object of the present invention is to provide a guide block and a friction stir welding method that can hold down the workpieces to suppress lifting and vibration even when the surfaces of a pair of members forming an inner corner are curved. [Means for solving the problem]

[0007] The guide block of the present invention is a guide block that holds a workpiece to be friction stir welded against an inner corner formed by a pair of workpieces, and is characterized in that it has a guide hole that rotatably holds the stirring pin, and a pair of guide rollers arranged on either side of the guide hole, and the guide rollers are capable of rolling on the surfaces of each of the pair of workpieces.

[0008] In the present invention, with the stirring pin inserted into the guide hole, the stirring pin and the guide block are brought close to the inner corners of the pair of workpieces, and a pair of guide rollers on both sides of the guide hole are brought into contact with the surfaces of the pair of workpieces to press them down, while the rotating stirring pin friction stir welds the intersection of the pair of workpieces. At this time, each pair of guide rollers abuts against the pair of engaged parts at two separate points. These two-point abutment can be maintained whether the surfaces of the pair of joined parts are flat or curved. Therefore, even if the surfaces of the pair of joined parts are both flat, one is curved, or both are curved, the pair of guide rollers on both sides of the guide hole abut against each of the two points on the pair of joined parts, thereby holding down the joined parts and suppressing lifting and vibration. The range of the curved surface that can maintain two-point contact with the workpieces varies depending on the distance between the guide rollers, the dimensions, and the shape. It is also preferable to adjust the protruding length of the stirring pin held in the guide hole depending on the curvature of the surface of the workpieces.

[0009] In the guide block of the present invention, the guide rollers are preferably spherical. In the present invention, since the guide roller is spherical, even if the angle between the pair of workpieces, i.e., the angle formed by the pair of surfaces forming the inner corner, is different, it is possible to maintain two points of contact with each of the workpieces, and to appropriately press the workpieces to suppress lifting and vibration. The spherical guide roller does not have to be a perfect sphere, but may have a flat cutout through which the rolling axis passes, as long as the area that rolls on the pair of workpieces is spherical.

[0010] In the guide block of the present invention, it is preferable that the guide rollers are flattened spheres whose rolling axis direction is short. In the present invention, the guide roller is flat and has a large outermost radius, so that it can be introduced even into inner corners where the angle between a pair of workpieces is small, thereby expanding the range of application.

[0011] In the guide block of the present invention, it is preferable that the guide rollers are in the shape of a pair of cones whose bottom surfaces are joined together. In the present invention, if the angle between the generatrix of the pair of conical shapes and the angle between the pair of workpieces are matched, the pair of conical surfaces formed on the guide roller will contact one and the other of the workpieces at a line rather than at a point, and the workpieces can be appropriately pressed down to prevent lifting or vibration. In other words, if the pair of guide rollers are spherical, the guide blocks have room to rotate relative to each of the workpieces around the line segment connecting the centers of the guide rollers. In contrast, if the pair of guide rollers are conical, there is no room for such rotation, and the orientation of the guide blocks relative to the non-contacting member is uniquely determined. However, the conical shape of the guide rollers limits the angle at which the workpieces can be sandwiched.

[0012] In the guide block of the present invention, it is preferable that the guide roller is cylindrical. In the present invention, both end edges of the cylindrical guide roller can roll on a pair of workpieces, respectively. Furthermore, because the guide roller is cylindrical, manufacturing is extremely easy. In the case of a cylindrical guide roller, it is preferable that both end edges that roll on the pair of workpieces be chamfered into a conical or spherical surface.

[0013] In the guide block of the present invention, it is preferable that the guide rollers are a pair of disk-shaped members arranged in parallel, one of which can abut against one of the workpieces and the other of which can abut against the other of the workpieces. In this invention, of the pair of disk-shaped members (a total of four as a pair of guide rollers arranged on either side of the guide hole), one abuts on one of the workpieces and the other abuts on the other workpiece. Therefore, even if the linear speed at each abutment point differs depending on the posture of the guide block and the pair of workpieces, the workpieces and disk-shaped members on each side can roll reliably, preventing slippage. Furthermore, since the guide roller is formed by a pair of disk-shaped members, the amount of material can be reduced and manufacturing can be facilitated. A pair of disc-shaped members used as guide rollers can be supported by the same rotation shaft. A collar can be placed between the pair of disc-shaped members to maintain their position. To prevent tilting with respect to the rotation shaft, the portions of the pair of disc-shaped members that are inserted into the rotation shaft can have a predetermined length (thickness as disc-shaped members) in the longitudinal direction of the rotation shaft. To ensure appropriate rolling relative to the workpieces, the cross-sectional shape of the peripheral edge of the disc-shaped member can be arc-shaped.

[0014] The friction stir welding method of the present invention is characterized in that, when friction stir welding is performed on an inner corner formed by a pair of workpieces, a guide block is used that has a guide hole that rotatably holds a stir pin and a pair of guide rollers arranged on either side of the guide hole, and the pair of guide rollers are rolled on each surface of the pair of workpieces. According to the friction stir welding method of the present invention, the same effects as those described above for the guide block of the present invention can be obtained. [Effects of the Invention]

[0015] According to the present invention, a guide block and a friction stir welding method are provided that can hold down the workpieces to suppress lifting and vibration even when the surfaces of a pair of members forming an inner corner are curved. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing friction stir welding according to a first embodiment of the present invention. [Figure 2] FIG. 3 is a plan view of the guide block according to the first embodiment. [Figure 3] FIG. 3 is a side view of the guide block according to the first embodiment. [Figure 4] FIG. 2 is a front view of the guide block according to the first embodiment. [Figure 5] FIG. 4 is a perspective view showing friction stir welding according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a side view of a guide block according to a third embodiment of the present invention. [Figure 7]FIG. 10 is a side view of a guide block according to a fourth embodiment of the present invention. [Figure 8] FIG. 10 is a side view of a guide block according to a fifth embodiment of the present invention. [Figure 9] FIG. 13 is a side view of a guide block according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [First embodiment] 1 to 4 show a first embodiment of the present invention. In FIG. 1, in this embodiment, friction stir welding is performed on an inner corner 4 of a workpiece 3 using a rotating tool 10 for inner corner welding attached to a spindle 2 of a machine tool 1. The workpiece 3 to be joined consists of a cylindrical body 5 and a cylindrical joint 6 joined to the inside of its end, and the end surface 7 of the cylindrical body 5 is flat, but the surface 8 of the joint 6 is cylindrical. In this embodiment, the joint 6, whose surface 8 is a cylindrical surface, corresponds to one of the members to be joined in the present invention, and the cylindrical body 5, whose end surface 7 is a flat surface, corresponds to the other member to be joined in the present invention. The inner corner 4 is formed between the end surface 7 and the surface 8, and the included angle, i.e., the angle between the end surface 7 and the surface 8, is 90 degrees.

[0018] 2, 3 and 4, the inner corner welding rotary tool 10 is configured by attaching a guide block 20 to a stirring pin 11 for friction stir welding. The guide block 20 has a plate-shaped base 21 formed by cutting a metal material or the like. A guide hole 22 for rotatably holding the stirring pin 11 is formed in the center of the base 21. Guide hole 22 has a bearing (not shown) inside, and is capable of rotatably holding stirring pin 11. The bearing of guide hole 22 includes a thrust bearing, and stirring pin 11 is inserted into guide hole 22 from above in the figure along central axis 22C, and is restricted from advancing in the state shown in Figures 2 and 3, and is maintained rotatably in a state where it protrudes from guide block 20 by a predetermined amount.

[0019] Support portions 23 extending toward the bottom surface are formed at the four corners of the base 21, and spherical guide rollers 24 are supported between a pair of opposing support portions 23 at both ends of the base 21 via shaft members 25. The entire surfaces of the pair of guide rollers 24 are spherical, but the portions facing the support portion 23 are flat. As shown in Figures 2 and 3, each guide roller 24 abuts against the surface 8 of the joint 6 (one of the members to be joined) at point 28 on the spherical portion, and also abuts against the end surface 7 of the cylindrical body 5 (the other member to be joined) at point 27.

[0020] In this embodiment, friction stir welding is performed in the following procedure. First, the stirring pin 11 is inserted into the guide hole 22 to form the rotary tool 10 for joining inner corners, which is then attached to the spindle 2. The machine tool 1 is then operated to bring the stirring pin 11 and guide block 20 close to the inner corner 4 of the workpiece 3, i.e., the joint portion sandwiched between the end face 7 of the cylindrical body 5 and the surface 8 of the joint 6. Next, while rotating the main shaft 2 to rotate the stirring pin 11, the pair of guide rollers 24 of the guide block 20 are brought into contact with the surface 8 and the end face 7, respectively, and the stirring pin 11 held in the guide hole 22 is pressed against the joint portion between the surface 8 and the end face 7, thereby starting the friction stir welding of the cylindrical body 5 and the joint 6. Next, while friction stirring the cylindrical body 5 and joint 6 with the stirring pin 11, the stirring pin 11 is moved along the joint between the surface 8 and end face 7, thereby sequentially friction stir welding the joint between the surface 8 and end face 7. During this process, guide rollers 24 roll on the surface 8 and end face 7 on both sides of the stirring pin 11, stabilizing the orientation of the guide block 20 or stirring pin 11 and further pressing down on the workpieces to prevent lifting or vibration.

[0021] According to this embodiment, the following effects can be obtained. In this embodiment, a pair of guide rollers 24 on either side of the guide hole 22 through which the stirring pin 11 is inserted is rolled on each surface (end face 7 and surface 8) of a pair of workpieces (cylindrical body 5 and joint 6), thereby pressing down on the workpieces to prevent them from lifting up or vibrating, and the rotating stirring pin 11 can friction stir weld the intersecting portion of the pair of workpieces.

[0022] At this time, each pair of guide rollers 24 abuts against the pair of engaged members at two separate points (two points 27 and two points 28 shown in FIG. 2). These two-point abutment can be maintained whether the surfaces of the pair of joined members are flat or curved. Therefore, even if the inner corner portion 4 is configured with the end surface 7 of the cylindrical body 5, which is flat, and the surface 8 of the joint 6, which is cylindrical, the pair of guide rollers 24 on both sides of the guide hole 22 abuts against each of the two points on the pair of joined members, thereby holding down the joined members and suppressing lifting and vibration. In the guide block 20 of this embodiment, the pair of guide rollers 24 on both sides of the guide hole 22 can abut against two points on each of the pair of workpieces, even when the surfaces of the workpieces are flat and curved, or even when both are flat or both are curved, thereby pressing down on the workpieces and preventing them from lifting up or vibrating.

[0023] Second Embodiment FIG. 5 shows a second embodiment of the present invention. In the first embodiment described above, the pair of workpieces to be friction stir welded are the cylindrical body 5 and joint 6 of the workpiece 3, the end surface 7 of the cylindrical body 5 is a flat surface, and the surface 8 of the joint 6 is a cylindrical surface. In contrast, in this embodiment, as shown in Figure 5, the workpieces 3A to be joined are cylindrical bodies 5A and 6A of the same diameter, and each edge is chamfered at a 45-degree angle to form conical inclined surfaces 7A and 8A, and these inclined surfaces 7A and 8A form the inner corner portion 4A.

[0024] In order to perform friction stir welding on such an inner corner 4A, this embodiment uses the same inner corner joining rotary tool 10 as in the first embodiment. As described in the first embodiment, the guide blocks 20 of the inner corner joining rotary tool 10 each have a pair of spherical guide rollers 24 (see FIGS. 2 to 4), so that contact can be made at a total of four points on the surfaces of a pair of workpieces even if both surfaces are curved. Therefore, in this embodiment, as in the first embodiment described above, the guide roller 24 rolls on the inclined surfaces 7A and 8A with the inner corner portion 4A in contact with the conical inclined surfaces 7A and 8A at four points, thereby pressing down on the workpieces to suppress lifting and vibration.

[0025] Third Embodiment FIG. 6 shows a third embodiment of the present invention. In the first embodiment described above, the pair of spherical guide rollers 24 are provided on the guide block 20 and roll on the pair of workpieces to be friction stir welded (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6). In contrast to this, in the guide block 20A of this embodiment, as shown in FIG. 6, the guide rollers 24A are formed in a flat spherical shape that is short in the rolling axis direction (the axial direction of the shaft member 25). In this embodiment, the guide roller 24A is flat and has a large outermost radius, so that the guide roller 24A can be introduced all the way to the inside of an inner corner 4 (see Figure 1) where the angle between a pair of workpieces (the end face 7 of the cylindrical body 5 and the surface 8 of the joint 6) is small, thereby expanding the range of application of the rotary tool 10 for joining inner corners.

[0026] [Fourth embodiment] FIG. 7 shows a fourth embodiment of the present invention. In the first embodiment described above, the pair of spherical guide rollers 24 are provided on the guide block 20 and roll on the pair of workpieces to be friction stir welded (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6). In contrast, in the guide block 20B of this embodiment, the guide rollers 24B are formed into a pair of cones whose bottom surfaces are joined together, as shown in Fig. 7. That is, the guide roller 24B has a conical surface 241 formed on one side in the rolling axis direction (axial direction of the shaft member 25) and an inverted conical surface 242 formed on the other side, with the outer circumferential surface therebetween being a cylindrical surface 243. Here, the angle of the generatrix of each of the conical surfaces 241 and 242 is 45 degrees with respect to the rolling axis, and the angle between the generatrix of each of the two surfaces is 90 degrees. As explained in the first embodiment, the angle between the end surface 7 and the surface 8 of the pair of workpieces (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6) on which the conical surfaces 241 and 242 roll is 90 degrees, and the angle of the conical surfaces 241 and 242 is set according to the angle between the pair of workpieces.

[0027] In this embodiment, the angle between the generatrix of the pair of conical shapes (conical surfaces 241, 242) of the guide roller 24B is made to match the angle between the pair of workpieces (the angle between the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6), so that the pair of conical surfaces 241, 242 contact one side of the workpieces (surface 8 of the joint 6) and the other side (end surface 7 of the cylindrical body 5) at lines 27B, 28B, rather than at points, thereby stably holding the guide block 20B and pressing down on the workpieces to prevent them from lifting up or vibrating. That is, when the pair of guide rollers 24 are spherical as in the first embodiment, there is room for the guide block 20 to rotate relative to each of the workpieces (the cylindrical body 5 and the joint 6) about the line segment connecting the centers of the guide rollers 24. In contrast, when the pair of conical surfaces 241, 242 in this embodiment are conical, there is no room for such rotation, and the orientation of the guide block 20B relative to the non-contact member is uniquely determined, allowing the stirring pin 11 to be guided appropriately in a more stable manner.

[0028] Fifth Embodiment FIG. 8 shows a fifth embodiment of the present invention. In the first embodiment described above, the pair of spherical guide rollers 24 are provided on the guide block 20 and roll on the pair of workpieces to be friction stir welded (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6). In contrast to this, in a guide block 20C of this embodiment, as shown in FIG. 8, a guide roller 24C is cylindrical. In this embodiment, the cylindrical guide roller 24C can roll on a pair of workpieces (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6) at points 27 and 28 on both end edges thereof. Furthermore, the cylindrical shape of the guide roller makes manufacturing extremely easy. In addition, it is preferable that both end edges of the cylindrical guide roller 24C that roll on the pair of workpieces be chamfered into a conical or spherical shape.

[0029] Sixth Embodiment FIG. 9 shows a fifth embodiment of the present invention. In the first embodiment described above, the pair of spherical guide rollers 24 are provided on the guide block 20 and roll on the pair of workpieces to be friction stir welded (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6). In contrast to this, in the guide block 20D of this embodiment, as shown in FIG. 9, a total of four disk-shaped guide rollers 24D are provided, each pair of two rollers sandwiching the guide hole 22.

[0030] Each of the four guide rollers 24D is formed by rounding the circumferential surface of a disk-shaped member, and the cross section of the outer periphery is arc-shaped or semicircular. Two guide rollers 24D, one pair on either side of the guide hole 22, are inserted into the same shaft member 25 and supported rotatably about its axis. The thickness of the guide roller 24D is ensured at the portion through which the shaft member 25 passes so as not to cause tilt with respect to the shaft member 25. A collar 25D is inserted into the middle portion of the shaft member 25, and the two guide rollers 24D supported by the same shaft member 25 are kept at a constant distance from each other by the collar 25D. Washers (not shown) inserted into the shaft member 25 may be attached between the two guide rollers 24D and the inner surface of the support portion 23.

[0031] As a result, in the guide block 20D of this embodiment, two guide rollers 24D are arranged in parallel with each other at an interval of the collar 25D inside the support portions 23 on both sides of the guide hole 22. The outer peripheries of these disk-shaped cylindrical guide rollers 24D can roll on the pair of workpieces (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6). In this embodiment, one and the other of a pair of guide rollers 24D supported by the same shaft member 25 contact one of the workpieces (end surface 7 of the cylindrical body 5) and the other workpiece (surface 8 of the joint 6), respectively. Therefore, even if the linear speed at each contact point differs depending on the posture of the guide block 20D and the pair of workpieces, the workpieces on each side and the guide rollers 24D contacting them can reliably roll, preventing slippage. Furthermore, because guide roller 24D is formed from a pair of disk-shaped members, it is possible to reduce material and facilitate manufacturing. Also, because two guide rollers 24D are supported by the same shaft member 25 and spaced apart by collar 25D, each part can be simplified, which also facilitates manufacturing.

[0032] Other Embodiments The present invention is not limited to the above-described embodiment, and includes modifications within the scope of achieving the object of the present invention. In the above embodiment, the base 21 and the support portion 23 are integrally formed, but the base 21 and the support portion 23 may be formed separately and joined together with bolts or the like. In the above embodiment, by increasing the thickness of base 21, the positional accuracy of stirring pin 11 inserted into guide hole 22, that is, the deviation or tilt between the central axis of stirring pin 11 and central axis 22C of guide hole 22, can be reduced. In the above embodiment, the range of the curved surface that can maintain two-point contact with a pair of workpieces (the end surface 7 of the cylindrical body 5 and the surface 8 of the joint 6 or the inclined surfaces 7A, 8A of the cylindrical bodies 5A, 6A) varies depending on the spacing and dimensions of the guide rollers 24 to 24C. In addition, it is preferable to adjust the protruding length of the stirring pin 11 held in the guide hole 22 depending on the curvature of the surfaces of the workpieces.

[0033] In each of the above-described embodiments, the base portion 21 or the support portion 23 may be provided with a coolant passage therein for dissipating heat generated during friction stir welding. In each of the above-described embodiments, the guide hole 22 may have a detachable divided structure in which a bearing or a support member that contacts the stirring pin 11 is detachably attached and detachably attached, and may be appropriately replaceable. [Industrial Applicability]

[0034] The present invention can be used as a guide block for inner corner friction stir welding and as a friction stir welding method. [Explanation of symbols]

[0035] 1...machine tool, 2...spindle, 3, 3A...workpiece, 4, 4A...inner corner portion, 5, 5A...cylindrical body which is the other of a pair of members to be welded, 6...joint which is one of the pair of members to be welded, 6A...cylindrical body which is one of the pair of members to be welded, 7...end face which is the surface of the other of the pair of members to be welded, 7A...inclined surface of the other of the pair of members to be welded, 8...surface of one of the pair of members to be welded, 8A...inclined surface which is the surface of one of the pair of members to be welded, 10...rotary tool for joining inner corners, 1 1...stirring pin, 20, 20A, 20B, 20C, 20D...guide block, 21...base, 22...guide hole, 22C...central axis, 23...support portion, 24, 24A, 24B, 24C, 24D...guide roller, 241...conical surface, 242...conical surface, 243...cylindrical surface, 25...shaft member, 25D...collar, 27, 28...points where a pair of members to be joined and the guide roller abut, 27B, 28B...lines where a pair of members to be joined and the guide roller abut.

Claims

1. A guide block that holds a workpiece to be friction stir welded against an inner corner formed by a pair of workpieces, The mixing device has a plate-shaped base, a guide hole formed in the base for rotatably holding a stirring pin, and a pair of guide rollers disposed on the bottom surface side of the base with the guide hole between them, The guide block is characterized in that the guide rollers are capable of rolling on the surfaces of the pair of workpieces.

2. 2. The guide block according to claim 1, A guide block characterized in that the guide rollers are spherical.

3. 3. The guide block according to claim 2, The guide block is characterized in that the guide rollers are flat spherical with a short rolling axis.

4. 2. The guide block according to claim 1, The guide block is characterized in that the guide rollers are a pair of conical shapes joined at their bottom sides.

5. 2. The guide block according to claim 1, The guide block is characterized in that the guide roller is cylindrical.

6. 2. The guide block according to claim 1, A guide block characterized in that the guide rollers are a pair of disk-shaped members arranged in parallel, one of the disk-shaped members being able to abut against one side of the workpieces and the other disk-shaped member being able to abut against the other side of the workpieces.

7. When performing friction stir welding on an inner corner formed by a pair of workpieces, A friction stir welding method using a guide block having a plate-shaped base, a guide hole formed in the base for rotatably holding a stirring pin, and a pair of guide rollers arranged on the bottom side of the base with the guide hole between them, characterized by rolling the pair of guide rollers on each surface of a pair of the workpieces.

Images