Rotary tool

Abstract

Provided is a rotary tool that does not readily cause excessive heat input and can suppress the occurrence of joining defects. A rotary tool (100) for friction stirring comprises: a base-end-side pin (104) in which a spiral first groove (121) is formed; and a distal-end-side pin (106) extending from the base-end-side pin (104), the distal-end-side pin (106) having a spiral second groove (131) formed therein. The taper angle of the base-end-side pin (104) is greater than the taper angle of the distal-end-side pin (106). The outside diameter (D1) of the base-end-side pin (104) and the outside diameter (D2) of the distal-end-side pin (106) satisfy the relationship "1.5 ≤ D1 / D2 ≤ 3.0."

Description

Rotate tool

[0001] The present invention relates to a rotary tool.

[0002] Patent Document 1 discloses a rotary tool for friction stir welding, in which the shoulder of the rotary tool is tapered and has a groove formed in the shoulder.

[0003] Japanese Patent Application Laid-Open No. 2003-320465

[0004] In order to perform good welding, it is important to control the frictional heat generated between the rotary tool and the workpieces during friction stir welding. However, while providing a spiral groove on the shoulder of the rotary tool as in Patent Document 1 can improve the stirring force of the rotary tool, it also has the problem of generating excessive frictional heat on the surfaces of the workpieces, making welding defects more likely to occur.

[0005] From this perspective, an object of the present invention is to provide a rotary tool that is less likely to experience excessive heat input and can suppress the occurrence of welding defects even when a spiral groove is provided on the shoulder portion of the rotary tool.

[0006] In order to solve the above problem, the present invention provides a friction stirring rotary tool comprising a base end pin having a first spiral groove formed therein, and a tip end pin extending from the base end pin and having a second spiral groove formed therein, wherein the taper angle of the base end pin is larger than the taper angle of the tip end pin, and the outer diameter D1 of the base end pin and the outer diameter D2 of the tip end pin have a relationship of 1.5≦D1 / D2≦3.0.

[0007] It is preferable that the groove width W of the first groove is 1.0 mm≦W≦2.8 mm, and the wall thickness L of the first groove is 0.1 mm≦L≦1.8 mm.

[0008] The groove depth Y of the first groove is preferably 0.2 mm≦Y≦1.0 mm.

[0009] The number of turns N of the first groove is preferably 1≦N≦5.2.

[0010] According to the present invention, it is possible to provide a rotary tool that is less likely to experience excessive heat input and can suppress the occurrence of welding defects even when a spiral groove is provided on the shoulder portion of the rotary tool.

[0011] 1A is a front view of a rotary tool according to a first embodiment. FIG. 1B is a cross-sectional view of a tip portion of the rotary tool according to the first embodiment. FIG. 1C is a bottom view of the rotary tool according to the first embodiment. FIG. 1D is a front view of a tip side pin member of the rotary tool according to the first embodiment. FIG. 1E is an enlarged cross-sectional view of a first groove in the rotary tool according to the first embodiment. FIG. 1F is an enlarged front view of a tip portion of the rotary tool according to the first embodiment. FIG. 1G is an exploded perspective view of a liquid cooling jacket that serves as a member to be joined according to the first embodiment. FIG. 1H is a cross-sectional view showing a placement step in a method for manufacturing a liquid cooling jacket according to the first embodiment. FIG. 1I is a cross-sectional view showing a main joining ... front view of a rotary tool according to a second embodiment. FIG. 1H is a cross-sectional view of a tip portion of the rotary tool according to the second embodiment. FIG. 1I is an enlarged front view of a tip portion of the rotary tool according to the second embodiment. FIG. 1I is a front view of a tip side pin member of the rotary tool according to the second embodiment. FIG. 1I is an enlarged cross-sectional view of a first groove in the rotary tool according to the second embodiment. FIG. 1I is an enlarged front view of a tip portion of the rotary tool according to the second embodiment. 1 is a photograph, substitute for a drawing, of a welded portion of welded members welded with the rotary tool according to the third embodiment. FIG. 2 is a diagram showing various parameters of the rotary tool according to the third embodiment. FIG. 3 is a photograph, substitute for a drawing, of a welded portion of welded members welded with the rotary tool according to the third embodiment. FIG. 4 is a photograph, substitute for a drawing, of a welded portion (planar) of welded members welded with the rotary tool according to the fourth embodiment. FIG. 5 is a photograph, substitute for a drawing, of a welded portion (cross section) of welded members welded with the rotary tool according to the fourth embodiment. FIG. 6 is a photograph, substitute for a drawing, of a welded portion (planar) of welded members welded with the rotary tool according to the comparative example. FIG. 7 is a photograph, substitute for a drawing, of a welded portion (cross section) of welded members welded with the rotary tool according to the comparative example.

[0012] The present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments. Furthermore, some or all of the components in each embodiment can be combined as appropriate.

[0013] First Embodiment <Configuration of Rotary Tool> First, the configuration of a rotary tool according to a first embodiment will be described with reference to Figures 1 to 6. The rotary tool is a tool used for friction stir welding. The rotary tool 100 is formed, for example, from tool steel, and is mainly composed of a base-side pin member 101 and a tip-side pin member 102.

[0014] The base-side pin member 101 includes an axial base shaft portion 103 and a base-side pin 104 extending from the tip side of the base shaft portion 103. The base shaft portion 103 has a truncated cone shape and is connected to the main shaft (not shown) of the friction stir welding device. The base-side pin 104 forms a shoulder portion of the rotary tool 100 and is inclined into a tapered shape. The tip-side pin member 102 includes an axial base shaft portion 105 and a tip-side pin 106 extending from the tip side of the base shaft portion 105. The base shaft portion 105 has a cylindrical shape and opens at the tip end of the tip-side pin member 102. The base shaft portion 105 is housed in a storage portion 107, which is a recess whose inner circumferential surface shape matches the outer circumferential surface shape of the base shaft portion 105. When the base shaft portion 105 is housed in the storage portion 107, only the tip-side pin 106 is exposed to the outside. The distal end pin 106 has a tapered shape, and the surface portion is inclined in a tapered shape.

[0015] The base-side pin member 101 has a threaded hole 108, and a screw is passed through this threaded hole to screw the distal-side pin member 102 to the base-side pin member 101 (the screw is not shown). Note that, although the example in this first embodiment shows a case where the base-side pin 104 and the distal-side pin 106 are separate members, the rotation tool 100 may also be manufactured by integrally molding the base-side pin 104 and the distal-side pin 106. Furthermore, the base-side pin member 101 and the distal-side pin member 102 may be fixed by a method such as fitting, and the fixing method is not limited to screwing.

[0016] The base pin 104 has a truncated cone shape. The taper angle A (see FIG. 6 ) of the base pin 104 may be set as appropriate, but the taper angle A is larger than the taper angle B of the tip pin 106. A first groove 121 is formed over the entire outer circumferential surface (shoulder portion) of the base pin 104. The first groove 121 is formed in a clockwise or counterclockwise spiral shape (a clockwise or counterclockwise spiral shape in plan view). In this first embodiment, the first groove 121 is set to rotate counterclockwise from the base end side to the tip end side in order to rotate the rotary tool 100 clockwise.

[0017] When the rotary tool 100 is rotated counterclockwise, it is preferable to set the first groove 121 clockwise from the base end side toward the tip end side of the base end pin 104. This allows the first groove 121 to guide the plastic flow material toward the tip end side, thereby reducing the amount of metal that overflows outside the joined metal members.

[0018] The tip-side pin 106 has a truncated cone shape. The tip of the tip-side pin 106 has a flat surface 109 perpendicular to the central axis of rotation. The taper angle B (see FIG. 6 ) of the tip-side pin 106 is smaller than the taper angle A of the base-side pin 104. A spiral second groove 131 is engraved on the outer circumferential surface of the tip-side pin 106. The second groove 131 is formed in a clockwise or counterclockwise spiral shape (a clockwise or counterclockwise spiral shape in plan view). The second groove 131 may be clockwise or counterclockwise, but in this first embodiment, the second groove 131 is engraved counterclockwise from the base end side to the tip end side of the tip-side pin 106 to rotate the rotary tool 100 clockwise.

[0019] 2, the relationship between the outer diameter D1 of the proximal pin 104 (the outer diameter of the proximal end of the proximal pin 104) and the outer diameter D2 of the distal pin 106 (the outer diameter of the proximal end of the distal pin 106) is "1.5≦D1 / D2≦3.0". Preferably, the relationship is "1.7≦D1 / D2≦2.7", and more preferably, "1.9≦D1 / D2≦2.3".

[0020] 5, the groove width W of the first groove 121 is "1.0 mm≦W≦2.8 mm", and the wall thickness L of the first groove 121 is "0.1 mm≦L≦1.8 mm". Preferably, "1.1 mm≦W≦1.6 mm" and "0.2 mm≦L≦0.5 mm", and more preferably, "1.2 mm≦W≦1.5 mm" and "0.3 mm≦L≦0.4 mm".

[0021] 5, the groove depth Y of the first groove 121 is "0.2 mm≦Y≦1.0 mm", preferably "0.2 mm≦Y≦0.8 mm", and more preferably "0.3 mm≦Y≦0.5 mm".

[0022] The number of turns N of the spiral first groove 121 is in the range of 1≦N≦5.2, preferably 1.4≦N≦4.4, and more preferably 1.7≦N≦3.7.

[0023] <Friction stir welding process> Next, a friction stir welding process performed using the rotary tool 100 will be described. In the following example, a liquid cooling jacket is manufactured by friction stir welding, and as shown in Fig. 7 and subsequent drawings, a jacket main body 2 and a sealing body 3 are used as welded members, and the jacket main body 2 and the sealing body 3 are joined by friction stir welding to manufacture the liquid cooling jacket 1. Note that the following example merely shows one example of a friction stir welding process using the rotary tool 100, and the welded members to be joined by the rotary tool 100 can be various products, and the following example does not limit the present invention.

[0024] As shown in FIG. 7 , the liquid cooling jacket 1 is composed of a jacket main body 2 and a sealing body 3. The liquid cooling jacket 1 is a device that cools a heat-generating element placed inside by circulating a fluid therein. The jacket main body 2 and the sealing body 3 are integrated by friction stir welding. In the following description, the "front surface" refers to the surface opposite to the "rear surface." The jacket main body 2 may be made of any metal that can be subjected to friction stir welding (aluminum, aluminum alloy, magnesium, magnesium alloy, copper, copper alloy, titanium, titanium alloy, etc.), but in the example of this first embodiment, it is made of an aluminum alloy.

[0025] The bottom 10 is a rectangular plate-like member. The peripheral wall 11 is a wall rising from the periphery of the bottom 10 in the shape of a rectangular frame. Support columns 12 rise from the bottom 10. There is no particular limitation on the number of support columns 12, but in this embodiment there are two. The bottom 10 and the peripheral wall 11 form a recess 13. Note that although the jacket body 2 in this embodiment is integrally formed, for example, the peripheral wall 11 may be divided and joined together with a sealing member to form an integrated structure. The support columns 12 may also be omitted.

[0026] A peripheral wall step 14 is formed on the end face 11a of the peripheral wall 11 along the inner periphery of the peripheral wall 11 of the jacket main body 2. The peripheral wall step 14 is composed of a step bottom 14a and a step side 14b rising from the step bottom 14a. The step bottom 14a is formed one step lower than the end face 11a. The step bottom 14a is at the same height as the end face 12a of the support 12. The sealing body 3 is a plate-shaped member that seals the opening of the jacket main body 2. The thickness of the side 3c of the sealing body 3 may be the same dimension as the height of the step side 14b, or may be greater than the height of the step side 14b. The sealing body 3 is not particularly limited as long as it is a metal that can be friction-stirred, but in this embodiment it is made of an aluminum alloy.

[0027] Next, a method for manufacturing the liquid cooling jacket according to the first embodiment will be described. The method for manufacturing the liquid cooling jacket according to the first embodiment includes a preparation step, a placement step, a first main joining step, and a second main joining step. The preparation step is a step for preparing the jacket main body 2 and the sealing body 3. There are no particular limitations on the manufacturing methods for the jacket main body 2 and the sealing body 3, but the jacket main body 2 is molded by die casting, for example. The sealing body 3 is molded by extrusion molding, for example.

[0028] As shown in Fig. 8, the placing process is a process of placing the sealing body 3 on the peripheral wall step portion 14 formed in the jacket main body 2. The step side surface 14b of the peripheral wall step portion 14 and the side surface 3c of the sealing body 3 are butted together to form a first butt joint J1. Furthermore, the step bottom surface 14a of the peripheral wall step portion 14 and the back surface 3b of the sealing body 3 are overlapped to form a second butt joint J2. Furthermore, the end surface 12a of the support 12 and the back surface 3b of the sealing body 3 are overlapped to form an overlap joint J3. The jacket main body 2 and the sealing body 3 may be temporarily joined by welding, friction stir welding, or the like.

[0029] As shown in Fig. 9, the first main welding process is a process of friction stir welding the first butt joint J1 using a rotary tool 100. While maintaining a "predetermined depth" and ensuring that the rotation center axis Z of the rotary tool 100 is perpendicular to the end face 11a of the peripheral wall portion 11 and the surface 3a of the sealing body 3, the rotary tool 100 is moved relatively along the first butt joint J1 to go around the jacket main body 2 and the sealing body 3. The predetermined depth of the rotary tool 100 may be set as appropriate. In the first main welding process, a plasticized region U1 is formed in the movement trajectory of the rotary tool 100.

[0030] In this embodiment, the base shaft portion 103 of the base pin member 101 is set to a predetermined depth so that it does not come into contact with the jacket body 2 and the sealing body 3, and the base pin 104 and the tip pin 106 are entirely in contact with the jacket body 2 and the sealing body 3. Alternatively, the predetermined depth may be set so that the end surface 11 a of the peripheral wall portion 11 and the surface 3 a of the sealing body 3 come into contact with the base pin 104 at about the center in the height direction.

[0031] As shown in FIG. 10 , the second main welding process is a process of friction stir welding the sealing body 3 and the support 12 using a rotary tool 100. In the second main welding process, the rotary tool 100 is inserted vertically into the surface 3a of the sealing body 3, and after moving relatively one or more times along the overlapping portion J3, the rotary tool 100 is removed from the sealing body 3. In the second main welding process, a plasticized region U2 is formed in the movement trajectory of the rotary tool 100. The predetermined depth of the rotary tool 100 in the second main welding process may be set appropriately, similar to the first main welding process. Note that the second main welding process may be omitted.

[0032] <Actions and Effects> The rotary tool 100 according to the first embodiment described above can achieve the following actions and effects. As described above, in the rotary tool 100, the outer diameter D1 of the base pin 104 and the outer diameter D2 of the tip pin 106 have a relationship of "1.5≦D1 / D2≦3.0." If D1 / D2 is less than 1.5, D1 is too small relative to the outer diameter D2, and the force pushing in the plastic flow material is weak, which may result in a welding defect. On the other hand, if D1 / D2 exceeds 3.0, the contact area between the base pin 104 and the workpieces becomes large, which results in excessive frictional heat being generated. In contrast to this, by providing the first groove 121 in the base end pin 104 (shoulder portion) as in this embodiment and by making the outer diameter D1 of the base end pin 104 and the outer diameter D2 of the tip end pin 106 satisfy the relationship "1.5≦D1 / D2≦3.0", it is possible to suppress the generation of frictional heat even if the amount of depression of the rotary tool 100 into the workpieces increases. This makes it possible to suppress the occurrence of welding defects in the welded portion of the workpieces.

[0033] Furthermore, the groove width W of the first groove 121 is "1.0 mm ≦ W ≦ 2.8 mm," and the wall thickness L of the first groove 121 is "0.1 mm ≦ L ≦ 1.8 mm." This allows the groove width W and wall thickness L of the first groove 121 to be set to appropriate sizes. That is, if the groove width W exceeds 2.8 mm, the recess of the first groove 121 becomes excessively large, and the frictional heat increases, which may result in a joint defect. On the other hand, if the groove width W is less than 1.0 mm, the frictional heat decreases, which may result in a decrease in the accuracy of friction stirring. By forming the groove width W of a scroll groove such as the first groove 121 within the above range, the agitated material that attempts to overflow is caused to flow toward the rotation center axis Z and accumulate in the base-end pin 104. Therefore, if the groove width W is reduced, the accumulation effect decreases, which may result in a surface defect. Furthermore, if the wall thickness L exceeds 1.8 mm, the distance between adjacent first grooves 121 becomes too large, reducing the friction stir welding function. In other words, if the wall thickness L becomes too large, the distance between the first grooves 121 increases, reducing the effect of the grooves (the effect of storing overflowing material) as described above, making surface defects more likely to occur. If the wall thickness L of the first grooves 121 is "0.1 mm≦L≦1.8 mm," good friction stir welding can be performed.

[0034] Furthermore, the groove depth Y of the first groove 121 is "0.2 mm≦Y≦1.0 mm". If the groove depth Y of the first groove 121 is less than 0.2 mm, the groove will not function as a groove. In other words, if the groove depth Y is too small, the effect of the groove (the effect of storing overflowing material) will be reduced, making surface defects more likely to occur. On the other hand, if the groove depth Y exceeds 1.0 mm, the groove will be too deep, making it more likely that the plastic flow material will remain in the groove, and the plastic flow material remaining in the groove may damage the workpieces. The rotary tool 100 of this embodiment can perform friction stir welding well by setting the groove depth Y within the above range.

[0035] The number of turns N of the spiral first groove 121 is in the range of 1≦N≦5.2. This allows the rotary tool 100 to perform good friction stir welding.

[0036] [Second embodiment] <Configuration of rotary tool> First, the configuration of a rotary tool according to the second embodiment will be described with reference to Figs. 11 to 16. The rotary tool is a tool used for friction stir welding. The rotary tool 200 is formed of, for example, tool steel, and is mainly composed of a base-side pin member 201 and a tip-side pin member 202.

[0037] The base-side pin member 201 includes an axial base shaft portion 203 and a base-side pin 204 extending from the tip side of the base shaft portion 203. The base shaft portion 203 is cylindrical and is connected to the main shaft (not shown) of the friction stir stirring device. The base-side pin 204 is a portion forming a shoulder portion of the rotary tool 200 and is inclined into a tapered shape. The tip-side pin member 202 includes an axial base shaft portion 205 and a tip-side pin 206 extending from the tip side of the base shaft portion 205. The base shaft portion 205 is cylindrical and opens at the tip end of the tip-side pin member 202. The base shaft portion 205 is housed in a storage portion 207, which is a recess whose inner circumferential surface shape matches the outer circumferential surface shape of the base shaft portion 205. When the base shaft portion 205 is housed in the storage portion 207, only the tip-side pin 206 is exposed to the outside. The distal end pin 206 has a tapered shape, and the surface portion is inclined in a tapered shape.

[0038] The base-end pin member 201 has a threaded hole 208, and a screw is passed through this threaded hole to screw the tip-end pin member 202 to the base-end pin member 201 (the screw is not shown). Note that, although the example in this second embodiment shows a case where the base-end pin 204 and the tip-end pin 206 are separate members, the rotation tool 200 may also be manufactured by integrally molding the base-end pin 204 and the tip-end pin 206.

[0039] The base pin 204 has a truncated cone shape. The taper angle A ( FIG. 16 ) of the base pin 204 may be set as appropriate, but the taper angle A is larger than the taper angle B of the tip pin 106. A first groove 221 is formed over the entire outer circumferential surface (shoulder portion) of the base pin 204. The first groove 221 is formed in a clockwise or counterclockwise spiral shape (a clockwise or counterclockwise spiral shape in plan view). In the second embodiment, the first groove 221 is set to rotate counterclockwise from the base end side to the tip end side in order to rotate the rotary tool 200 clockwise.

[0040] When rotating the rotary tool 200 counterclockwise, it is preferable to set the first groove 221 clockwise from the base end of the base pin 204 toward the tip end. This allows the first groove 221 to guide the plastic flow material toward the tip end, thereby reducing the amount of metal spilling out of the welded metal members. The tip pin 206 has a truncated cone shape. The tip of the tip pin 206 forms a flat surface 209 perpendicular to the rotation axis. A groove may be formed on the flat surface 209. The taper angle B ( FIG. 16 ) of the tip pin 206 is smaller than the taper angle A ( FIG. 16 ) of the base pin 204. A spiral second groove 231 is engraved on the outer peripheral surface of the tip pin 206. The second groove 231 is formed in a clockwise or counterclockwise spiral shape (a clockwise or counterclockwise spiral shape in plan view).

[0041] 12, the relationship between the outer diameter D1 of the proximal pin 204 (the outer diameter of the proximal end of the proximal pin 204) and the outer diameter D2 of the distal pin 206 (the outer diameter of the proximal end of the distal pin 206) is "1.5≦D1 / D2≦3.0". Preferably, the relationship is "1.7≦D1 / D2≦2.7", and more preferably, "1.9≦D1 / D2≦2.3".

[0042] 15 , the groove width W of the first groove 221 is "1.0 mm≦W≦2.8 mm", and the wall thickness L of the first groove 221 is "0.1 mm≦L≦1.8 mm". Preferably, "1.1 mm≦W≦1.6 mm" and "0.2 mm≦L≦0.5 mm", and more preferably, "1.2 mm≦W≦1.5 mm" and "0.3 mm≦L≦0.4 mm".

[0043] 15, the groove depth Y of the first groove 221 is "0.2 mm≦Y≦1.0 mm", preferably "0.4 mm≦Y≦0.9 mm", and more preferably "0.5 mm≦Y≦0.8 mm".

[0044] The number of turns N of the spiral first groove 221 is in the range of 1≦N≦5.2, preferably 1.5≦N≦4.5, and more preferably 2.0≦N≦4.5.

[0045] As is clear from a comparison of the drawings of both embodiments, the structural differences between the rotary tool 100 of the first embodiment and the rotary tool 200 of the second embodiment are mainly in the size of each part, and the technical matters characteristic of the present invention are almost the same in both embodiments.

[0046] <Friction Stir Welding Step> The friction stir welding step of the second embodiment is the same as that of the first embodiment, and therefore a detailed description thereof will be omitted.

[0047] <Actions and Effects> The rotary tool 200 according to the second embodiment described above can achieve the following actions and effects. As described above, in the rotary tool 200, the outer diameter D1 of the base pin 204 and the outer diameter D2 of the tip pin 206 satisfy the relationship "1.5≦D1 / D2≦3.0." If D1 / D2 is less than 1.5, D1 is too small relative to the outer diameter D2, and the force pushing in the plastic flow material is weak, which may result in a welding defect. On the other hand, if D1 / D2 exceeds 3.0, the contact area between the base pin 204 and the workpieces becomes large, which results in excessive frictional heat being generated. In contrast to this, by providing the first groove 221 in the base end pin 204 (shoulder portion) as in this embodiment and by making the outer diameter D1 of the base end pin 204 and the outer diameter D2 of the tip end pin 106 have the relationship "1.5≦D1 / D2≦3.0", it is possible to suppress the generation of frictional heat even if the amount of depression of the rotary tool 200 into the workpieces increases. This makes it possible to suppress the occurrence of welding defects in the welded portion of the workpieces.

[0048] Furthermore, the groove width W of the first groove 221 is "1.0 mm ≦ W ≦ 2.8 mm," and the wall thickness L of the first groove 221 is "0.1 mm ≦ L ≦ 1.8 mm." This allows the groove width W and wall thickness L of the first groove 221 to be set to appropriate sizes. That is, if the groove width W exceeds 2.8 mm, the recess of the first groove 221 may become excessively large, which may increase the frictional heat. On the other hand, if the groove width W is less than 1.0 mm, the frictional heat may be reduced, which may reduce the accuracy of the friction stirring. By forming the groove width W of a scroll groove such as the first groove 221 within the above range, the agitated material that attempts to overflow is caused to flow toward the rotation center axis Z and accumulate in the base-end pin 204. Therefore, if the groove width W is reduced, the accumulation effect may be reduced, which may increase the likelihood of surface defects. Furthermore, if the wall thickness L exceeds 1.8 mm, the distance between adjacent first grooves 221 becomes too large, reducing the friction stir welding function. In other words, if the wall thickness L becomes too large, the distance between the first grooves 221 increases, reducing the effect of the grooves (the effect of storing overflowing material) as described above, making surface defects more likely to occur. If the wall thickness L of the first grooves 221 is "0.1 mm≦L≦1.8 mm," good friction stir welding can be performed.

[0049] Furthermore, the groove depth Y of the first groove 221 is "0.2 mm≦Y≦1.0 mm". If the groove depth Y of the first groove 221 is less than 0.2 mm, the groove will not function as a groove. In other words, if the groove depth Y is too small, the effect of the groove (the effect of storing overflowing material) will be reduced, making surface defects more likely to occur. On the other hand, if the groove depth Y exceeds 1.0 mm, the groove will be too deep, making it more likely that the plastic flow material will remain in the groove, which may damage the workpieces. The rotary tool 200 of this embodiment can perform friction stir welding well by setting the groove depth Y within the above range.

[0050] The number of turns N of the spiral first groove 221 is in the range of 1≦N≦5.2. This allows the rotary tool 200 to perform good friction stir welding.

[0051] Below, several examples of the present invention and several comparative examples are given, but the present invention is not limited to the following examples.

[0052] [First Example] Fig. 17 is a diagram showing various parameters of a rotary tool according to a first example of the present invention. Here, a total of 10 examples are shown, examples a1 to a5 and b1 to b5. Examples a1 to a5 are examples of the rotary tool 100. Examples b1 to b5 are examples of the rotary tool 200. Fig. 20 shows various parameters for the "outer diameter" of the rotary tool and the "first groove" (the first grooves 121, 221) in each of these examples, broadly speaking.

[0053] The parameters of "outer diameter" include "D1" (mm), which is the outer diameter D1 of the base-side pins 104, 204 (outer diameter of the base ends of the base-side pins 104, 204), "D2" (mm), which is the outer diameter D2 of the tip-side pins 106, 206 (outer diameter of the base ends of the tip-side pins 106, 206), and the ratio between them, "D1 / D2," as described above. The parameters of "first groove" include, with respect to the first grooves 121, 221, "pitch" (mm), which is the pitch, "groove width" (mm), which is the groove width W, which is the groove width, "number of turns" which is the number of turns N, "wall thickness" (mm), which is the wall thickness L, "groove depth" (mm), which is the groove depth Y, and "R" (mm), which is the radius of curvature of the groove.

[0054] In Example a1, D1 was 8.5 mm, D2 was 4 mm, D1 / D2 was 2.1, pitch was 1.2 mm, groove width was 1.0 mm, number of turns was 1.8, wall thickness was 0.3 mm, groove depth was 0.3 mm, and R was 0.6 mm. In Example a2, D1 was 8.5 mm, D2 was 3 mm, D1 / D2 was 2.8, pitch was 1.2 mm, groove width was 1.0 mm, number of turns was 2.3, wall thickness was 0.3 mm, groove depth was 0.3 mm, and R was 0.6 mm.

[0055] In Example a3, D1 was 8.5 mm, D2 was 5 mm, D1 / D2 was 1.7, pitch was 1.2 mm, groove width was 1.0 mm, number of turns was 1.4, wall thickness was 0.3 mm, groove depth was 0.3 mm, and R was 0.6 mm. In Example a4, D1 was 8.5 mm, D2 was 4 mm, D1 / D2 was 2.1, pitch was 1.0 mm, groove width was 1.0 mm, number of turns was 2.2, wall thickness was 0.1 mm, groove depth was 0.3 mm, and R was 0.6 mm.

[0056] Example a5 had D1 of 8.5 mm, D2 of 4 mm, D1 / D2 of 2.1, pitch of 1.5 mm, groove width of 1.0 mm, number of turns of 1.0, wall thickness of 0.6 mm, groove depth of 0.3 mm, and R of 0.6 mm. Example b1 had D1 of 30 mm, D2 of 14 mm, D1 / D2 of 2.1, pitch of 2.0 mm, groove width of 1.4 mm, number of turns of 4.1, wall thickness of 0.7 mm, groove depth of 0.5 mm, and R of 0.75 mm.

[0057] In Example b2, D1 was 30 mm, D2 was 10 mm, D1 / D2 was 3.0, pitch was 2.0 mm, groove width was 1.4 mm, number of turns was 5.2, wall thickness was 0.7 mm, groove depth was 0.5 mm, and R was 0.75 mm. In Example b3, D1 was 30 mm, D2 was 18 mm, D1 / D2 was 1.7, pitch was 2.0 mm, groove width was 1.4 mm, number of turns was 3.0, wall thickness was 0.7 mm, groove depth was 0.5 mm, and R was 0.75 mm.

[0058] In Example b4, D1 was 30 mm, D2 was 14 mm, D1 / D2 was 2.1, pitch was 3.0 mm, groove width was 1.4 mm, number of turns was 2.8, wall thickness was 1.8 mm, groove depth was 0.5 mm, and R was 0.75 mm. In Example b5, D1 was 30 mm, D2 was 14 mm, D1 / D2 was 2.1, pitch was 3.5 mm, groove width was 2.8 mm, number of turns was 2.2, wall thickness was 0.9 mm, groove depth was 1.0 mm, and R was 1.5 mm. In Examples a1 to a5, A5052 (aluminum alloy) and ADC12 (aluminum alloy) were friction stir welded using the rotary tools of each of the above examples. In addition, in Examples b1 to b5, A1050 (aluminum alloy) and C1020 (copper alloy) were friction stir welded using the rotary tools of each of the above examples. The bonded portion of each example was observed to carefully determine whether any bonding defects had occurred.

[0059] As a result, no joint defects were observed in all of Examples a1 to a5 and b1 to b5, and the joint state was good. In addition, considering that there were almost no burrs in the joints, it can be inferred that frictional heat during friction stirring was also suppressed.

[0060] Second Example Figure 18 is a diagram showing various parameters of a rotary tool according to a second example of the present invention. In this second example (Example c1), A5052 (aluminum alloy) and ADC12 (aluminum alloy) were used as the workpieces. The rotary tool 100 was used, with a rotation speed of 2000 rpm and a welding speed of 750 mm / min. In Example c1, D1 was 8.5 mm, D2 was 4 mm, D1 / D2 was 2.1, pitch was 1.2 mm, groove width was 1.2 mm, number of turns was 1.8, wall thickness was 0.16 mm, groove depth was 0.3 mm, and R was 0.6 mm.

[0061] Figure 19 is a photograph showing an enlarged cross section of the welded components of Example c1. The symbol U indicates the plasticized region. As is clear from the photograph, no weld defects were observed in the welded portion between A5052 (symbol 301) and ADC12 (symbol 302), and the weld condition was good. Furthermore, considering that there was almost no burr in the welded portion, it can be inferred that frictional heat during friction stirring was also suppressed.

[0062] [Third Example] Figure 20 is a diagram showing various parameters of a rotary tool according to a third example of the present invention. In this third example (Example d1), A1050 (aluminum alloy) and C1020 (copper alloy) were used as the workpieces. The rotary tool 200 was used, with a rotation speed of 700 rpm and a welding speed of 100 mm / min. In Example d1, D1 was 30 mm, D2 was 14 mm, D1 / D2 was 2.1, pitch was 2.0 mm, groove width was 1.5 mm, number of turns was 4.1, wall thickness was 0.5 mm, groove depth was 0.5 mm, and R was 0.75 mm.

[0063] Figure 21 is a photograph showing an enlarged cross section of the welded members of Example d1. As is clear from the photograph, no weld defects were observed in the welded portion between A1050 (reference numeral 311) and C1020 (reference numeral 312), and the weld condition was good. Furthermore, considering that there was almost no burr in the welded portion, it can be inferred that frictional heat during friction stirring was also suppressed.

[0064] 22 and 23 are enlarged photographs of the welded members according to this fourth example. In this fourth example (Example e), A5052 (aluminum alloy) and ADC12 (aluminum alloy) were used as the welded members. The rotary tool 100 was used, with a rotation speed of 4000 rpm and a welding speed of 500 mm / min. In Example e, D1 was 8.5 mm, D2 was 4 mm, D1 / D2 was 2.1, and the taper angle A was 130°.

[0065] Figure 22 shows the surface of the welded parts after welding. The symbol U indicates the plasticized region. As shown in the photograph substituted for the same drawing, no welding defects were observed in the welded parts. Figure 23 shows the cross section of the welded parts after welding. As shown in the photograph substituted for the same drawing, some burrs were generated in the welded parts, but no welding defects were observed in the joint between A5052 (reference symbol 321) and ADC12 (reference symbol 322), and the weld condition was good. In addition, considering that the amount of burrs was small, it can be inferred that frictional heat during friction stirring was also suppressed.

[0066] 24 and 25 are enlarged photographs of welded members according to a comparative example to the above-described examples (particularly the fourth example). In this comparative example, A5052 (aluminum alloy) and ADC12 (aluminum alloy) were used as welded members. The rotary tool 100 used had a rotation speed of 4000 rpm and a welding speed of 500 mm / min. In this comparative example, D1 was 12.5 mm, D2 was 4 mm, D1 / D2 was 3.1, and the taper angle A was 130°.

[0067] Figure 24 shows the surfaces of the welded parts after joining. The symbol U indicates the plasticized region. As shown in the photograph substituted for the same drawing, it can be seen that defects have occurred on the surfaces of the welded parts (see Figure 24). Figure 25 shows a cross section of the welded parts after joining. As shown in the photograph substituted for the same drawing, a joint defect has occurred at the joint between A5052 (reference symbol 401) and ADC12 (reference symbol 402). It can also be seen that a large amount of burrs is emitted (see Figure 25).

[0068] [Discussion] Comparing the above-described examples with the comparative example, the following can be considered. It has been found that, in the rotary tools 100, 200, if the outer diameter D1 of the base end pin 104, 204 and the outer diameter D2 of the tip end pin 106, 206 have the relationship "1.5≦D1 / D2≦3.0", the amount of heat input to the workpieces can be set to an appropriate value, and the occurrence of welding defects in the workpieces can be suppressed. Furthermore, if "2.0≦D1 / D2≦3.0", it is considered that welding defects in the workpieces can be reliably suppressed. Furthermore, if "2.3≦D1 / D2≦2.7", it is considered that welding defects in the workpieces can be more reliably suppressed.

[0069] It has been found that if the groove width W of the first grooves 121, 221 is in the relationship "1.0 mm≦W≦2.8 mm" and the wall thickness L of the first groove 221 is in the relationship "0.1 mm≦L≦1.8 mm," the amount of heat input to the workpieces during friction stir welding can be set to an appropriate value, and the occurrence of welding defects in the workpieces can be suppressed. Also, if "1.1 mm≦W≦1.6 mm" and "0.2 mm≦L≦0.5 mm" are satisfied, it is believed that welding defects in the workpieces can be reliably suppressed. Furthermore, if "1.2 mm≦W≦1.5 mm" and "0.3 mm≦L≦0.4 mm" are satisfied, it is believed that welding defects in the workpieces can be more reliably suppressed.

[0070] It was found that if the groove depth Y of the first grooves 121, 221 is "0.2 mm≦Y≦1.0 mm", the amount of heat input to the workpieces can be set to an appropriate value, and the occurrence of joining defects in the workpieces can be suppressed. Also, if "0.4 mm≦D≦0.9 mm", it is thought that joining defects in the workpieces can be reliably suppressed. Furthermore, if "0.5 mm≦D≦0.8 mm", it is thought that joining defects in the workpieces can be more reliably suppressed.

[0071] It was also found that if the number of turns N of the spiral first groove 221 is "1≦N≦5.2", the amount of heat input to the workpieces can be set to an appropriate value, and the occurrence of joining defects in the workpieces can be suppressed. It is also believed that if "1.5≦N≦4.5", joining defects in the workpieces can be reliably suppressed. Furthermore, if "2.0≦N≦4.0", it is believed that joining defects in the workpieces can be more reliably suppressed.

[0072] 100, 200 Rotating tool 104, 204 Base end pin (shoulder portion) 106, 206 Tip end pin 121, 221 First groove 131, 231 Second groove A Taper angle B Taper angle D1 Outer diameter D2 Outer diameter W Groove width L Wall thickness Y Groove depth N Number of turns

Claims

1. A friction stirring rotary tool comprising: a base end pin having a first helical groove formed therein; and a tip end pin extending from said base end pin and having a second helical groove formed therein; wherein the taper angle of said base end pin is greater than the taper angle of said tip end pin; and an outer diameter D1 of said base end pin and an outer diameter D2 of said tip end pin satisfy the relationship 1.5≦D1 / D2≦3.

0.

2. The rotary tool according to claim 1, characterized in that the groove width W of the first groove is 1.0 mm≦W≦2.8 mm, and the wall thickness L of the first groove is 0.1 mm≦L≦1.8 mm.

3. The rotary tool according to claim 1, characterized in that the groove depth Y of the first groove is 0.2 mm≦Y≦1.0 mm.

4. The rotary tool according to claim 1, characterized in that the number of turns N of the first groove is 1≦N≦5.2.

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