Friction Stir Welding Tool

Abstract

To provide a friction agitation joint tool which can prevent mixture of a skin material peeled from a workpiece surface.SOLUTION: A friction agitation joint tool 1 has a rod-like tool body 10 extending along a rotation axis A, an agitation pin 11 projecting from the center part of a processing side end face of the tool body 10, and a shoulder part 12 formed on the processing side end face that is outside the agitation pin 11, and is rotationally driven in a predetermined processing direction R and performs friction agitation joint of a joint part of a pair of workpieces 3, wherein the friction agitation joint tool has a spiral filament part 121 for discharge formed along the outer periphery of the shoulder part 12, and the spiral shape of the filament part 121 for discharge is made to be a spiral shape expanded outside from inside when the tool body 10 is rotated in the processing direction R.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a friction stir welding tool.

Background Art

[0002] Friction stir welding is performed using a machine tool equipped with a friction stir welding tool. The friction stir welding tool has a stirring pin at the tip surface of a rod-shaped tool body, and the region outside the stirring pin on the tip surface of the tool body is a shoulder portion. The friction stir welding tool is mounted on the main spindle of a machine tool, and while rotating, the stirring pin is pressed into the joint portion of a pair of workpieces and moved along the joint portion. In the joint portion, the materials of the pair of workpieces are softened and stirred by the frictional heat between the stirring pin, and while the softened material is held by the shoulder portion, the pair of workpieces are joined to each other along the joint portion.

[0003] In the friction stir welding tools of Patent Documents 1 and 2, screw-shaped stripes are formed on the stirring pin, and in order to plasticize the surface portion of the workpiece, spiral stirring ridges are also formed on the shoulder portion of the tool body. The stirring ridges are spiral and reach inward as the tool rotates during processing, and have the effect of guiding the plasticized material inward, that is, toward the stirring pin, during processing. On the other hand, there is a skin such as an oxide film on the workpiece surface, and if the skin material peeled off during processing mixes into the workpiece material at the joint portion, it will lead to a deterioration in the quality of the product. Therefore, in the friction stir welding tool of Patent Document 2, the skin material is peeled off on the outer periphery of the tool body. On the other hand, in the friction stir welding tool of Patent Document 1, the skin material is peeled off by the peeling ridge on the outer periphery of the stirring ridge, preventing it from mixing into the joint portion.

[0004] In the friction stir welding tool of Patent Document 3, a deburring cutter is formed on the portion along the tip surface of the outer peripheral side surface of the tool body, and burrs, that is, portions protruding from the workpiece material, generated on the surface of the joined workpiece are removed. In the friction stir welding tools of Patent Documents 4 and 5, when there are irregularities on the surface of the workpiece to be welded, or when a temporary bead is pre-applied to the workpiece, a cutter is provided to remove these irregularities, and burr removal is also possible with this cutter.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to the friction stir welding tools of Patent Documents 1 and 2 described above, the skin on the surface of the workpiece can be peeled off during friction stir welding. Also, similar peeling effects can be expected with the friction stir welding tools of Patent Documents 3 to 5. However, the skin material peeled off from the workpiece surface may become minute fragments and get caught between the shoulder part and the workpiece, mix into the softened workpiece material, and potentially degrade the quality of the welded workpiece. In particular, with the friction stir welding tools of Patent Documents 1 and 2, the fragments of the film mixed in with the softened material are induced inward toward the stirring pin by the stirring protrusions on the shoulder part, which may exacerbate the degradation of the quality of the workpiece material.

[0007] An object of the present invention is to provide a friction stir welding tool capable of preventing the mixing of the skin material peeled off from the workpiece surface.

Means for Solving the Problems

[0008] The friction stir welding tool of the present invention has a rod-shaped tool body extending along a rotation axis, a stirring pin protruding from the center of the machining side end face of the tool body, and a shoulder portion formed on the machining side end face outside the stirring pin, and is a friction stir welding tool that is rotationally driven in a predetermined machining direction to perform friction stir welding of a joint portion of a pair of workpieces. It has a spiral discharge line portion formed along the outer circumference of the shoulder portion, and the spiral shape of the discharge line portion is a spiral shape that expands from the inside to the outside when the tool body rotates in the machining direction.

[0009] In such a present invention, the tool body is supported by the main shaft of a machine tool, and while rotating, the stirring pin is immersed in the joint portion of the workpiece to soften the workpiece material by frictional heat, so that friction stir welding of the workpiece can be performed. Here, the workpiece material around the stirring pin immersed in the joint portion of the workpiece is in a softened state due to the frictional heat with the stirring pin, and is pressed by the shoulder portion around the stirring pin so as not to overflow from the workpiece surface. In the present invention, a spiral stirring line portion is formed along the outer circumference of the shoulder portion, and the spiral shape of the discharge line portion is a spiral shape that expands from the inside to the outside when the tool body rotates in the machining direction. Therefore, the softened workpiece material in contact with the discharge line portion is discharged to the outside of the tool body. Therefore, even if fragments of the skin material peeled off from the surface of the workpiece are mixed between the shoulder portion and the workpiece material, they can be discharged to the outside by the discharge line portion. In particular, since the discharge line portion is formed along the outer circumference of the shoulder portion, the intrusion of the fragments of the skin material into the shoulder portion itself can be suppressed.

[0010] In the friction stir welding tool of the present invention, it preferably has a spiral stirring line portion formed in a region between the discharge line portion of the shoulder portion and the stirring pin, and the spiral shape of the stirring line portion is a spiral shape that goes from the outside to the inside when the tool body rotates in the machining direction.

[0011] In such an invention of the present disclosure, a discharge stripe portion is formed in an outer region along the outer periphery at the shoulder portion, and a stirring stripe portion is formed in an inner region close to the stirring pin. Since the stirring stripe portion is in a spiral shape directed from the outside toward the inside when the tool body rotates in the processing direction, the softened workpiece material in contact with the stirring stripe portion is introduced toward the inside where the stirring pin is located. Therefore, the skin material mixed into the workpiece material is discharged to the outside by the outer discharge stripe portion, and the workpiece material without the skin material mixed therein is guided toward the stirring pin by the inner stirring stripe portion, enabling appropriate friction stir welding.

[0012] In the friction stir welding tool of the present disclosure, a spiral outer peripheral stripe portion is formed on the side surface of the tool body, and a cutting blade portion for peeling the skin of the workpiece is formed at the end of the outer peripheral stripe portion facing the shoulder portion. The spiral shape of the outer peripheral stripe portion is preferably a spiral shape directed away from the shoulder portion when the tool body rotates in the processing direction.

[0013] In such an invention of the present disclosure, a cutting blade portion is formed at the outer peripheral edge of the shoulder portion, and the skin on the workpiece surface can be peeled off and removed. The fragments of the peeled skin material are prevented from mixing into the workpiece material by the discharge stripe portion as described above. Further, the cutting blade portion is formed at the end of the outer peripheral stripe portion, and the outer peripheral stripe portion is in a spiral shape directed away from the shoulder portion when the tool body rotates in the processing direction. Therefore, the fragments of the skin material generated at the cutting blade portion can be kept away from the shoulder portion and prevented from mixing into the workpiece material in contact with the shoulder portion.

[0014] In the friction stir welding tool of the present disclosure, a spiral pin stripe portion is formed on the side surface of the stirring pin. The spiral shape of the pin stripe portion is preferably a spiral shape directed toward the tip of the stirring pin when the tool body rotates in the processing direction.

[0015] In such an invention, the work material is softened by friction with the stirring pin, and friction stir welding is performed. At this time, a pin stripe portion is formed on the side surface of the stirring pin, and the spiral shape of the pin stripe portion is a spiral shape that approaches the tip of the stirring pin when the tool body rotates in the processing direction. Therefore, the softened work material around the stirring pin is sequentially guided to the tip side of the stirring pin, that is, the side away from the work surface, and efficient friction stir welding can be performed while suppressing overflow from the work surface.

Effect of the Invention

[0016] According to the present invention, it is possible to provide a friction stir welding tool that can prevent the inclusion of the skin material peeled off from the work surface.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0018] In FIG. 1, the friction stir welding tool 1 is mounted on the main shaft 2 of a machine tool, is rotationally driven in a predetermined processing direction R, and is moved along the joint portion of a pair of workpieces 3, thereby performing friction stir welding of the workpieces 3. The friction stir welding tool 1 includes a rod-shaped tool body 10 extending along a rotation axis A, a stirring pin 11 protruding from the center of the processing side end surface of the tool body 10, and a shoulder portion 12 formed on the processing side end surface outside the stirring pin 11.

[0019] In FIG. 2, a discharge stripe portion 121 is formed in an outer region along the outer circumference of the shoulder portion 12, and a stirring stripe portion 122 is formed in an inner region close to the stirring pin 11. The boundary 123 between the discharge line portion 121 and the stirring line portion 122 is circular with the rotation axis A as the center. The outer peripheral edge 124 of the shoulder portion 12 is not a perfect circle but a circular shape with four waveforms because the cutting blade portion 102 described later is formed.

[0020] The discharge line portion 121 is composed of spiral strip lines formed as protrusions in the region between the boundary 123 and the outer peripheral edge 124 of the shoulder portion 12. The spiral shape of the discharge line portion 121 is a spiral that expands from the inside to the outside when the tool body 10 rotates in the processing direction R. The stirring line portion 122 is composed of spiral strip lines formed as protrusions in the region between the boundary 123 of the shoulder portion 12 and the stirring pin 11. The spiral shape of the stirring line portion 122 is a spiral that goes from the outside to the inside when the tool body 10 rotates in the processing direction R. That is, in the discharge line portion 121 and the stirring line portion 122, the respective spiral shapes are opposite to each other.

[0021] On the side surface of the tool body 10, an outer peripheral line portion 101 composed of spiral concave grooves is formed. The cutting blade portion 102 is formed by the end portion of the outer peripheral line portion 101 facing the shoulder portion 12. The spiral shape of the outer peripheral line portion 101 is a spiral in a direction away from the shoulder portion 12 when the tool body 10 rotates in the processing direction R. On the side surface of the stirring pin 11, a pin line portion 111 composed of spiral protrusions is formed. The spiral shape of the pin line portion 111 is a spiral in a direction approaching the tip of the stirring pin 11 when the tool body 10 rotates in the processing direction R.

[0022] When performing friction stir welding using such a friction stir welding tool 1, each part of the friction stir welding tool 1 acts as follows. In friction stir welding, first, the tool body 10 is fixed to the main shaft 2 of the machine tool to attach the friction stir welding tool 1, and a pair of workpieces 3 to be joined are fixed to the table of the machine tool. Next, the main shaft 2 is rotated and the friction stir welding tool 1 is moved and placed at the joint portion of the pair of workpieces 3. Then, the friction stir welding tool 1 is lowered toward the workpiece 3, the stirring pin 11 is pressed against the joint portion of the workpiece 3, the workpiece 3 is softened by frictional heat, and the stirring pin 11 is immersed in the workpiece 3.

[0023] In FIG. 3, in a state where the friction stir welding tool 1 is rotating in a predetermined processing direction R and the stirring pin 11 is immersed in the joint portion of the workpiece 3, a softened region 30 in which the materials of the pair of workpieces 3 are softened is formed around the stirring pin 11. In the softened region 30, the surface of the softened material of the workpiece 3 is pressed by the shoulder portion 12.

[0024] Of the softened material of the workpiece 3 in contact with the shoulder portion 12, the workpiece material 32 inside the boundary 123 is induced inward toward the stirring pin 11 by the stirring stripe portion 122. This is because the stirring stripe portion 122 is in a spiral shape that moves from the outside to the inside when rotating in the processing direction R. The workpiece material 32 induced around the stirring pin 11 is induced downward by the pin stripe portion 111 on the side surface of the stirring pin 11 and sent as the workpiece material 33 from the vicinity of the surface to the bottom of the softened region 30. This is because the pin stripe portion 111 is in a spiral shape that approaches the tip of the stirring pin 11 when rotating in the processing direction R.

[0025] Due to the flow of the workpiece materials 32 and 33 like this, the stirring of the material of the workpiece 3 in the softened region 30 is promoted, and the pair of workpieces 3 are joined to each other in the softened region 30. In this state, by horizontally moving the friction stir welding tool 1 along the joint portion of the workpiece 3 while it is rotating by the machine tool, the pair of workpieces 3 are joined at the joint portion.

[0026] When the friction stir welding tool 1 is horizontally moved along the joint portion of the workpiece 3, the skin 4 such as the oxide film covering the surface of the workpiece 3 is cut off by the cutting edge portion 102 on the outer periphery of the shoulder portion 12. The fragments 41 of the cut-off skin are scattered around the tool body 10. A part of the scattered fragments 41 can be discharged upward by the outer peripheral striation portion 101 formed on the outer periphery of the tool body 10.

[0027] Another part of the scattered fragments 41 may enter between the shoulder portion 12 and the workpiece 3. Among the softened workpiece material 3 of the workpiece 3 in contact with the shoulder portion 12, the workpiece material 31 outside the boundary 123 is induced outward by the discharge striation portion 121. This is because the stirring striation portion 122 is in a spiral shape that rotates from the inside to the outside when rotating in the processing direction R. Therefore, even if another part of the scattered fragments 41 enters between the shoulder portion 12 and the workpiece 3 and mixes into the workpiece material 31, the workpiece material 31 is discharged to the outside of the softening region 30, and the influence on the joint quality of the workpiece 3 is suppressed.

[0028] According to such an embodiment, the following effects can be obtained. In this embodiment, the tool body 10 is supported by the main shaft 2 of the machine tool and rotated while the stirring pin 11 is immersed in the joint portion of the workpiece 3 to soften the material of the workpiece 3 by frictional heat, so that the friction stir welding of the workpiece 3 can be performed. Here, the material of the workpiece 3 around the stirring pin 11 immersed in the joint portion of the workpiece 3 is in a softened state due to the frictional heat with the stirring pin 11, and is pressed by the shoulder portion 12 around the stirring pin 11 so as not to overflow from the surface of the workpiece 3. In this embodiment, a spiral discharge striation portion 121 is formed along the outer periphery of the shoulder portion 12, and the discharge striation portion 121 is in a spiral shape that expands from the inside to the outside when the tool body 10 rotates in the processing direction R. Therefore, the softened workpiece material 31 in contact with the discharge striation portion 121 is discharged to the outside of the tool body 10. Therefore, even if fragments 41 of the material of the skin 4 peeled off from the surface of the workpiece 3 are mixed between the shoulder portion 12 and the material of the workpiece 3, they can be discharged to the outside by the discharge strip portion 121. In particular, since the discharge strip portion 121 is formed along the outer periphery of the shoulder portion 12, it is possible to prevent the fragments 41 of the skin material from entering the shoulder portion 12 itself.

[0029] In the present embodiment, a discharge strip portion 121 is formed in an outer region along the outer periphery in the shoulder portion 12, and a stirring strip portion 122 is formed in an inner region close to the stirring pin 11. Since the stirring strip portion 122 is in a spiral shape from the outside toward the inside when the tool body 10 rotates in the processing direction R, the softened workpiece material 32 in contact with the stirring strip portion 122 is introduced to the inside where the stirring pin 11 is located. Therefore, the skin material mixed into the workpiece material 31 is discharged to the outside by the outer discharge strip portion 121, and the workpiece material 32 without the mixing of the skin material is guided toward the stirring pin 11 by the inner stirring strip portion 122, and appropriate friction stir welding can be performed.

[0030] In the present embodiment, a cutting edge portion 102 is formed at the outer peripheral edge of the shoulder portion 12, and the skin 4 on the surface of the workpiece 3 can be peeled off and removed. The fragments 41 of the peeled skin material are prevented from being mixed into the workpiece material 31 by the discharge strip portion 121 as described above. Further, the cutting edge portion 102 is formed at the end of the outer peripheral strip portion 101, and the outer peripheral strip portion 101 is in a spiral shape away from the shoulder portion 12 when the tool body 10 rotates in the processing direction R. Therefore, the fragments 41 of the skin material generated at the cutting edge portion 102 can be kept away from the shoulder portion 12 and prevented from being mixed into the workpiece material 31 in contact with the shoulder portion 12.

[0031] In this embodiment, the material of the workpiece 3 is softened by friction with the stirring pin 11, and friction stir welding is performed. At this time, a pin stripe portion 111 is formed on the side surface of the stirring pin 11, and the spiral shape of the pin stripe portion 111 is a spiral shape that approaches the tip of the stirring pin 11 when the tool body 10 rotates in the processing direction R. Therefore, the softened workpiece material 33 around the stirring pin 11 is sequentially guided to the tip side of the stirring pin 11, that is, the side away from the surface of the workpiece 3, and efficient friction stir welding can be performed while suppressing overflow from the surface of the workpiece 3.

[0032] Note that the present invention is not limited to the above-described embodiment, and modifications within the scope that can achieve the object of the present invention are included in the present invention. In the above embodiment, the cutting edge portion 102 is not limited to being formed at the end of the outer peripheral stripe portion 101, and may have other configurations, such as an independent protrusion row formed on the outer periphery of the end of the tool body 10. Further, if the skin 4 of the workpiece 3 can be removed by contact with the outer periphery of the tool body 10, the cutting edge portion 102 may be omitted.

[0033] In the above embodiment, the pin stripe portion 111 formed on the side surface of the stirring pin 11 may be omitted. In the above embodiment, the discharge stripe portion 121 is formed in the outer region along the outer periphery of the shoulder portion 12, and the stirring stripe portion 122 is formed in the inner region close to the stirring pin 11. However, the stirring stripe portion 122 may be omitted, and in that case, the inner region of the shoulder portion 12 may be a flat surface or the like, or the discharge stripe portion 121 may be extended to the inner region. In the above embodiment, as the pin stripe portion 111, the discharge stripe portion 121, and the stirring stripe portion 122, grooves may be engraved on the side surface of the stirring pin 11 or the surface of the shoulder portion 12 to form protrusions, or they may be transferred by molding on the same side surface or surface, and any processing method can be used.

Industrial Applicability

[0034] The present invention can be used as a friction stir welding tool.

Explanation of Reference Numerals

[0035] 1…Friction stir welding tool, 10…Tool body, 101…Peripheral line part, 102…Cutting edge part, 11…Stirring pin, 111…Pin line part, 12…Shoulder part, 121…Discharge line part, 122…Stirring line part, 123…Boundary, 124…Outer periphery, 2…Spindle, 3…Workpiece, 30…Softening area, 31…Workpiece material, 32…Workpiece material, 33…Workpiece material, 4…Skin, 41…Fragment, A…Axis of rotation, R…Processing direction.

Claims

1. A friction stir welding tool having a rod-shaped tool body extending along a rotation axis, a stirring pin protruding from the center of the machining side end face of the tool body, and a shoulder portion formed on the machining side end face outside the stirring pin, and being rotationally driven in a predetermined machining direction to perform friction stir welding of a joint portion of a pair of workpieces, having a spiral discharge line portion formed along the outer periphery of the shoulder portion, The friction stir welding tool, wherein the spiral shape of the discharge line portion is a spiral shape that expands from the inside to the outside when the tool body rotates in the machining direction.

2. The friction stir welding tool according to claim 1, having a spiral stirring line portion formed in a region between the discharge line portion of the shoulder portion and the stirring pin, The friction stir welding tool, wherein the spiral shape of the stirring line portion is a spiral shape that goes from the outside to the inside when the tool body rotates in the machining direction.

3. The friction stir welding tool according to claim 1 or claim 2, A spiral outer peripheral line portion is formed on the side surface of the tool body, and a cutting edge portion for peeling the skin of the workpiece is formed by an end portion of the outer peripheral line portion facing the shoulder portion, The friction stir welding tool, wherein the spiral shape of the outer peripheral line portion is a spiral shape that moves away from the shoulder portion when the tool body rotates in the machining direction.

4. The friction stir welding tool according to claim 1 or claim 2, A spiral pin line portion is formed on the side surface of the stirring pin, The friction stir welding tool, wherein the spiral shape of the pin line portion is a spiral shape that approaches the tip of the stirring pin when the tool body rotates in the machining direction.

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