Friction stir joining device and friction stir joining method

Abstract

To facilitate removal of an inner diameter receiving jig after friction stir joining.SOLUTION: A friction stir joining device 10, which friction stir joins a first joined member 11 having a hollow cylindrical shape, and a second joined member 12 that has the hollow cylindrical shape and has at least an inner diameter substantially equal to or less than an inner diameter of the first joined member 11 at a joint place 20, includes: an inner diameter receiving jig 13 which has an outer peripheral surface smaller in diameter than the inner diameter of the second joined member 12, and supports at least a part of a cylindrical inner surface of the second joined member 12; a joined member rotation mechanism 14 for rotationally driving the first joined member 11 and the second joined member 12; an inner diameter receiving jig rotation mechanism 15 capable of rotating the inner diameter receiving jig 13; and a probe 16 for applying friction force to the joined place 20 by being brought into contact with the joined place 20 while being rotated, and decenters the rotation shaft of the inner diameter receiving jig 13 to the side of the probe 16, with respect to the rotation shafts of the first joined member 11 and the second joined member 12.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a friction stir welding apparatus and a friction stir welding method. [Background technology]

[0002] Motors used to drive automobiles and other vehicles generate a large amount of heat, so heat generation is generally reduced by installing a cooling device. One motor cooling device is a hollow cylindrical motor case installed around the motor's periphery, which has a cooling circuit, a space for circulating cooling air or cooling water, inside it. This motor case is formed, for example, by fitting two hollow cylindrical members to be joined that have different diameters together with a radial gap between them and joining them at the joint points.

[0003] Friction stir welding is a well-known technique for joining two hollow cylindrical workpieces at a joining point. For example, Patent Document 1 below discloses a friction stir welding method in which a probe is brought into contact with a joining point provided on two hollow cylindrical workpieces in a rotating state, and the joining point is joined by moving the probe in the circumferential direction of the hollow cylinder while softening and stirring the joining point with frictional heat. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-112272 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a probe is brought into contact with the welding point with a relatively large force as in the above-mentioned method, there is a risk of distortion of the cylindrical shape of the workpieces. Therefore, the inventors came up with a method of friction stir welding hollow cylindrical workpieces while maintaining their shape by placing a support jig that supports the workpieces on the opposite side of the welding point on the outer periphery of the two workpieces. However, depending on the shape of the support jig, there was a problem in that it was difficult to remove the support jig after friction stir welding.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a friction stir welding device and a friction stir welding method using the same in which the receiving jig can be easily removed after friction stir welding. [Means for solving the problem]

[0007] The present invention will be described below. In order to facilitate understanding of the present invention, reference numbers in the accompanying drawings are added in parentheses, but the present invention is not limited to the illustrated forms.

[0008] The friction stir welding device (10) according to the present invention is a friction stir welding device (10) that friction stir welds a hollow cylindrical first workpiece (11) and a hollow cylindrical second workpiece (12) that has an inner diameter that is at least substantially the same as or smaller than the inner diameter of the first workpiece (11) at a welding location (20), and includes an inner diameter receiving jig (13) that has an outer circumferential surface that is smaller in diameter than the inner diameter of the second workpiece (12) and supports at least a portion of the cylindrical inner surface of the second workpiece (12), a workpiece rotation mechanism (14) that rotates the first workpiece (11) and the second workpiece (12), an inner diameter receiving jig rotation mechanism (15) that rotates the inner diameter receiving jig (13), and a rotation mechanism (16) that rotates the inner diameter receiving jig (13) at the welding location (20). and a probe (16) that applies a frictional force to the joint (20) by contacting it, wherein, with at least a portion of the cylindrical inner surface of the second member to be welded (12) supported by the inner diameter receiving jig (13), the probe (16) is brought into contact with the joint (20) while being rotated, and the first member to be welded (11), the second member to be welded (12), and the inner diameter receiving jig (13) rotate around a rotation axis that is oriented in a different direction from the rotation axis of the probe (16), thereby friction stir welding the joint (20).The rotation axis of the inner diameter receiving jig (13) is eccentric toward the probe (16) with respect to the rotation axes of the first member to be welded (11) and the second member to be welded (12).

[0009] In the friction stir welding apparatus (10) according to the present invention, when the eccentric dimension of the rotation shaft in the inner diameter receiving jig (13) is L and the diameter of the inner diameter receiving jig (13) is R, 0.001≦L / R≦0.005 It is preferable that the rotation axis of the inner diameter receiving jig (13) is eccentric with respect to the rotation axes of the first member to be welded (11) and the second member to be welded (12) so that the following inequality holds.

[0010] In the friction stir welding apparatus (10) according to the present invention, the inner diameter receiving jig (13) can be configured to rotate freely by the inner diameter receiving jig rotating mechanism (15).

[0011] Furthermore, in the friction stir welding apparatus (10) according to the present invention, the inner diameter receiving jig (13) may be configured to be rotated by the inner diameter receiving jig rotating mechanism (15).

[0012] The friction stir welding method according to the present invention is a friction stir welding method for joining a hollow cylindrical first workpiece (11) and a hollow cylindrical second workpiece (12) having an inner diameter substantially equal to or smaller than the inner diameter of at least the first workpiece (11) at a joining location (20), the method including: an inner diameter receiving jig (13) having an outer circumferential surface with a diameter smaller than the inner diameter of the second workpiece (12) and supporting at least a part of the cylindrical inner surface of the second workpiece (12); a workpiece rotation mechanism (14) for rotating the first workpiece (11) and the second workpiece (12); an inner diameter receiving jig rotation mechanism (15) for rotatably driving the inner diameter receiving jig (13); and a rotating mechanism (15) for rotating the inner diameter receiving jig (13) so as to abut against the joining location (20). and a probe (16) that applies a frictional force to a cylindrical support jig (20) of the first workpiece (11) and the second workpiece (12). The method is characterized in that, using a friction stir welding apparatus (10) including the inner diameter support jig (13), with at least a portion of the cylindrical inner surface of the second workpiece (12) supported by the inner diameter support jig (13), the probe (16) is brought into contact with the welding location (20) while rotating, the first workpiece (11), the second workpiece (12) and the inner diameter support jig (13) are rotated around a rotation axis that is oriented differently from the rotation axis of the probe (16), and the inner diameter support jig (13) is rotated with the rotation axis of the inner diameter support jig (13) eccentric to the probe (16) side with respect to the rotation axes of the first workpiece (11) and the second workpiece (12). [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a friction stir welding apparatus in which the receiving jig can be easily removed after friction stir welding, and a friction stir welding method using the same. [Brief explanation of the drawings]

[0014] [Figure 1]1 is a cross-sectional view showing a first workpiece and a second workpiece to be welded which are friction stir welded using the friction stir welding apparatus according to the present embodiment. [Figure 2] 2 is a cross-sectional view showing a state in which the first member to be joined and the second member to be joined shown in FIG. 1 are fitted together. FIG. [Figure 3] FIG. 1 is a cross-sectional view showing the basic configuration of the friction stir welding apparatus according to this embodiment, illustrating a state in which a first workpiece to be welded and a second workpiece to be friction stir welded by the friction stir welding apparatus are fitted together and installed. [Figure 4] 1 is a cross-sectional view for explaining a friction stir welding method using a friction stir welding device according to an embodiment of the present invention. FIG. [Figure 5] 3 is a schematic view of a cylindrical cross section of a first member to be joined, a second member to be joined, and an inner diameter receiving jig. FIG. [Figure 6] FIG. 10 is a cross-sectional view showing the basic configuration of a friction stir welding apparatus according to another embodiment, illustrating a state in which a first workpiece to be welded and a second workpiece to be friction stir welded by the friction stir welding apparatus are fitted together and installed. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments for carrying out the present invention will be described below with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0016] First, the configuration of a first member to be welded 11 and a second member to be welded 12 to be joined by friction stir welding will be described with reference to Figures 1 and 2. Here, Figure 1 is a cross-sectional view showing the first member to be welded 11 and the second member to be welded 12 to be friction stir welded using the friction stir welding device according to this embodiment. Figure 2 is a cross-sectional view showing the first member to be welded 11 and the second member to be welded 12 shown in Figure 1 in a fitted state.

[0017] 1, the first member to be joined 11 is hollow and cylindrical, and has a first bottom portion 11a, a first diameter portion 11b, and an end portion 11c. The first bottom portion 11a is formed at one end of the first diameter portion 11b, and the end portion 11c is formed at the other end. The first member to be joined 11 is made of a metal material, such as an aluminum alloy called AC2B.

[0018] The second member to be joined 12 is hollow and cylindrical, and includes a second bottom portion 12a, a second diameter portion 12b, and a second large diameter portion 12c. The inner diameter of the second diameter portion 12b is smaller than the inner diameter of the first diameter portion 11b. The outer diameter of the second diameter portion 12b is substantially the same as the inner diameter of the first diameter portion 11b, and a plurality of grooves 121b, each smaller in diameter than the outer diameter of the second diameter portion 12b, are formed on a portion of the outer circumferential surface. The second diameter portion 12b includes a second bottom portion 12a at one end and a second large diameter portion 12c at the other end. Similar to the first member to be joined 11, the second member to be joined 12 is made of a metal material, such as an aluminum alloy, e.g., AC2B.

[0019] 2, the first member to be joined 11 and the second member to be joined 12 can be fitted together with the first bottom portion 11a and the second bottom portion 12a in contact with each other, and the first diameter portion 11b and the second diameter portion 12b in contact with each other. When the first member to be joined 11 and the second member to be joined 12 are fitted together, the central axes of the cylinders of the first member to be joined 11 and the second member to be joined 12 are aligned.

[0020] Furthermore, when the first member to be joined 11 and the second member to be joined 12 are fitted together, the step portion 12d formed in the second large diameter portion 12c abuts against the end portion 11c of the first member to be joined 11, forming a joining point 20.

[0021] Furthermore, while the inner diameter of the first diameter portion 11b and the outer diameter of the second diameter portion 12b are substantially the same, the outer diameter of the multiple grooves 121b formed in the second diameter portion 12b is smaller than the inner diameter of the first diameter portion 11b, so when the first member to be joined 11 and the second member to be joined 12 are fitted together, a space is created between the first diameter portion 11b and the second diameter portion 12b. This space can function as a cooling circuit, such as that formed in a motor cover or the like.

[0022] The basic configuration of the first workpiece 11 and the second workpiece 12 to be joined by friction stir welding in the friction stir welding apparatus 10 according to this embodiment has been described above. Next, the basic configuration of the friction stir welding apparatus 10 according to this embodiment will be described with reference to Figs. 3 to 5.

[0023] Fig. 3 is a cross-sectional view showing the basic configuration of a friction stir welding apparatus 10 according to this embodiment, showing a state in which a first workpiece 11 and a second workpiece 12 to be friction stir welded by the friction stir welding apparatus 10 are fitted together and installed. Fig. 4 is a cross-sectional view for explaining a friction stir welding method using the friction stir welding apparatus according to this embodiment. Fig. 5 is a schematic view of a cylindrical cross section of the first workpiece 11 and the second workpiece 12 to be friction stir welded by the friction stir welding apparatus 10, and the inner diameter receiving jig.

[0024] The friction stir welding apparatus 10 according to this embodiment includes an inner diameter receiving jig 13 , a workpiece rotating mechanism 14 , an inner diameter receiving jig rotating mechanism 15 , and a probe 16 .

[0025] The inner diameter receiving jig 13 is cylindrical and has an outer diameter smaller than the inner diameter of the second large diameter portion 12c of the second workpiece 12. When friction stir welding is performed by the friction stir welding apparatus 10, the inner diameter receiving jig 13 is placed on the inner surface of the second workpiece 12 at a location where the second large diameter portion 12c is formed. Furthermore, by being positioned so that part of the cylindrical outer circumferential surface of the inner diameter receiving jig 13 comes into contact with part of the inner surface of the second large diameter portion 12c, the inner diameter receiving jig 13 supports part of the inner surface of the second workpiece 12.

[0026] The workpiece rotation mechanism 14 includes a workpiece rotation mechanism base 14a, a workpiece rotation mechanism shaft 14b, a workpiece rotation mechanism rotation part 14c, and a bearing 14e. The workpiece rotation mechanism base 14a is fixed to a mounting reference surface G, such as a ground surface. The workpiece rotation mechanism shaft 14b is cylindrical and rotatably mounted via a bearing 14e mounted on the workpiece rotation mechanism base 14a. Furthermore, it is capable of rotational motion when provided with a rotational driving force from a motor (not shown). The workpiece rotation mechanism rotation part 14c is formed integrally with the workpiece rotation mechanism shaft 14b and grips a portion of the first bottom part 11a of the first workpiece 11. As a result, when the workpiece rotation mechanism shaft part 14b rotates, the workpiece rotation mechanism rotation part 14c, the first workpiece 11, and the second workpiece 12 fitted thereto can rotate in the same direction as the workpiece rotation mechanism shaft part 14d. Here, the workpiece rotation shaft 14d, which is the rotation center of the first workpiece 11 and the second workpiece 12, is installed so that it coincides with the central axis of the column of the workpiece rotation mechanism shaft part 14b.

[0027] The inner diameter receiving jig rotation mechanism 15 includes an inner diameter receiving jig rotation mechanism base 15a, an inner diameter receiving jig rotation mechanism shaft 15b, and a bearing 15e. The inner diameter receiving jig rotation mechanism base 15a is fixedly installed on an installation reference surface G such as a ground surface. The inner diameter receiving jig rotation mechanism shaft 15b is cylindrical and rotatably supports the inner diameter receiving jig 13 via a bearing 15e arranged on its outer circumferential surface. This allows the inner diameter receiving jig 13 to freely rotate around the inner diameter receiving jig rotation shaft 15d. Here, the inner diameter receiving jig rotation shaft 15d, which is the rotation center of the inner diameter receiving jig 13, is installed so as to coincide with the central axis of the cylinder of the inner diameter receiving jig rotation mechanism shaft 15b. In this embodiment, the inner diameter receiving jig rotation mechanism shaft portion 15b supports the inner diameter receiving jig 13 via the bearing 15e, but any rotation support means other than the bearing 15e may be used as long as it can support the inner diameter receiving jig 13 so that it can rotate freely.

[0028] The probe 16 is located approximately vertically above the joint 20 and also approximately vertically above a portion of the cylindrical outer circumferential surface of the inner diameter receiving jig 13 that supports the inner surface of the joint 20. The probe 16 can apply a frictional force to the joint 20 by coming into contact with the joint 20 while rotating.

[0029] 5, the inner diameter receiving jig rotation shaft 15d is configured to be eccentric toward the probe 16 with respect to the workpiece rotation shaft 14d. In the friction stirring apparatus 10 according to this embodiment, when the eccentric dimension of the inner diameter receiving jig rotation shaft 15d with respect to the workpiece rotation shaft 14d is L and the diameter of the inner diameter receiving jig 13 is R, 0.001≦L / R≦0.005 The inner diameter receiving jig rotation shaft 15d is configured to be eccentric with respect to the workpiece rotation shaft 14d so that the following inequality holds.

[0030] The basic configuration of the friction stir welding apparatus 10 according to this embodiment has been described above. Next, a friction stir welding method according to this embodiment will be described with reference to Fig. 4. In Fig. 4, similar to Fig. 3, the workpiece rotation mechanism rotation part 14c in the workpiece rotation mechanism 14 holds the first workpiece 11 fitted with the second workpiece 12. The inner diameter receiving jig 13 supports the inner surface side of the second workpiece 12 with a part of the cylindrical outer circumferential surface of the inner diameter receiving jig 13.

[0031] From this state, the probe 16 is rotated and brought into contact with the welding location 20 so that the first workpiece 11 and the second workpiece 12 are sandwiched between the probe 16 and the inner diameter support jig 13, and the workpiece rotation mechanism 14 rotates the first workpiece 11 and the second workpiece 12 about the workpiece rotation axis 14d. At this time, the inner diameter support jig 13 supports the second workpiece 12 with part of its cylindrical outer circumferential surface, generating a frictional force between the inner diameter support jig 13 and the second workpiece 12. Due to this frictional force, the inner diameter support jig 13 freely rotates in the same direction as the first workpiece 11 and the second workpiece 12 as the first workpiece 11 and the second workpiece 12 rotate. Furthermore, as the first workpiece 11 and the second workpiece 12 rotate, the welding points 20 move relative to the probe 16, and the welding points 20 formed on the peripheral surfaces of the first workpiece 11 and the second workpiece 12 are subjected to a frictional stirring force based on the rotational movement of the probe 16, thereby being frictionally stirred and welded sequentially.

[0032] After all the welding points 20 have been welded, the probe 16 is moved away from the welding points 20, thereby completing the friction stir welding method according to this embodiment.

[0033] When the above-described friction stir welding method is carried out, as shown in FIG. 5, the inner diameter receiving jig rotation shaft 15d is offset by a distance L toward the probe 16 side with respect to the welded member rotation shaft 14d.

[0034] That is, because gaps 22 are formed between the first and second workpieces 11, 12 and the inner diameter receiving jig 13, it becomes easy to remove the inner diameter receiving jig 13 after friction stir welding. This makes it possible to shorten production time while maintaining the welding quality of the first and second workpieces 11, 12 joined by the friction stir welding method, thereby improving mass productivity. In addition, the presence of gaps 22 makes it easier for air to flow, which allows the heat generated during friction stir welding to be efficiently diffused and removed.

[0035] If the ratio (L / R) of the eccentricity dimension L to the diameter R of the inner diameter receiving jig 13 is less than 0.001, the size of the resulting gap 22 will be insufficient, making it difficult to remove the inner diameter receiving jig 13 after friction stir welding. On the other hand, if the ratio (L / R) of the eccentricity dimension L to the diameter R of the inner diameter receiving jig 13 exceeds 0.005, distortion will be more likely to occur in the first workpiece 11 and the second workpiece 12 when they are friction stir welded at the welding location 20, leading to a deterioration in quality. Therefore, it is desirable to set the ratio (L / R) of the eccentricity dimension L to the diameter R of the inner diameter receiving jig 13 within a range in which the above-mentioned inequality holds.

[0036] While the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various modifications and improvements can be made to the above embodiments.

[0037] In the friction stir welding apparatus 10 according to the above-described embodiment, the inner diameter receiving jig 13 is rotatably supported via a bearing 15e arranged on the outer peripheral surface of the inner diameter receiving jig rotation mechanism shaft portion 15b in the inner diameter receiving jig rotation mechanism 15. In this case, the inner diameter receiving jig 13 is able to freely rotate in the same direction as the first workpiece 11 and the second workpiece 12 in accordance with the rotational movements of the first workpiece 11 and the second workpiece 12. However, the scope of the present invention is not limited to the above-described embodiment.

[0038] Here, a specific example in which the inner diameter receiving jig according to the present invention is rotationally driven by an inner diameter receiving jig rotation mechanism will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view showing the basic configuration of a friction stir welding apparatus 100 according to another embodiment, showing a state in which a first workpiece 11 and a second workpiece 12 to be friction stir welded by the friction stir welding apparatus 100 are fitted together and installed. In Fig. 6, components that are the same as or similar to those in the above-described embodiment are given the same reference numerals and will not be described again.

[0039] 6, in a friction stir welding apparatus 100 according to another embodiment, the inner diameter receiving jig 130 is cylindrical and has an outer diameter smaller than the inner diameter of the second large diameter portion 12c of the second workpiece 12. Furthermore, part of the cylindrical outer circumferential surface of the inner diameter receiving jig 130 contacts part of the inner surface of the second large diameter portion 12c, so that the inner diameter receiving jig 130 supports part of the inner surface side of the second workpiece 12.

[0040] The inner diameter receiving jig rotation mechanism 150 includes an inner diameter receiving jig rotation mechanism base 150a, an inner diameter receiving jig rotation mechanism shaft 150b, and a bearing 150e. The inner diameter receiving jig rotation mechanism base 150a is fixedly installed on an attachment reference surface G such as a ground surface. The inner diameter receiving jig rotation mechanism shaft 150b is cylindrical and rotatably installed via a bearing 150e installed on the inner diameter receiving jig rotation mechanism base 150a. Furthermore, it is capable of rotational movement when a rotational driving force is applied from a motor (not shown). The inner diameter receiving jig 130 is fixedly installed on the inner diameter receiving jig rotation mechanism shaft 150b, and therefore, when the inner diameter receiving jig rotation mechanism shaft 150b is rotated, the inner diameter receiving jig 130 can rotate. Here, an inner diameter receiving jig rotation axis 150d, which is the rotation center of the inner diameter receiving jig 130, is installed so as to coincide with the central axis of the column of the inner diameter receiving jig rotation mechanism shaft portion 150b.

[0041] The inner diameter receiving jig rotation shaft 150d is configured to be eccentric to the workpiece rotation shaft 14d toward the probe 16. Here, when the eccentric dimension of the inner diameter receiving jig rotation shaft 150d with respect to the workpiece rotation shaft 14d is L and the diameter of the inner diameter receiving jig 130 is R, 0.001≦L / R≦0.005 The inner diameter receiving jig rotation shaft 150d is configured to be eccentric with respect to the workpiece rotation shaft 14d so that the following inequality holds.

[0042] From this state, the probe 16 is rotated and brought into contact with the welding location 20 so that the first workpiece 11 and the second workpiece 12 are sandwiched between the probe 16 and the inner diameter receiving jig 130, and the workpiece rotation mechanism 14 rotates the first workpiece 11 and the second workpiece 12 about the workpiece rotation axis 14d. At this time, the inner diameter receiving jig 130 and the first workpiece 11 and the second workpiece 12 are also rotated by a motor (not shown) provided on the inner diameter receiving jig rotation mechanism 150 so that their respective rotational speeds are synchronized. As a result, the welding location 20 moves relative to the probe 16 as the first workpiece 11 and the second workpiece 12 rotate, and the welding locations 20 formed on the circumferential surfaces of the first workpiece 11 and the second workpiece 12 receive a friction stir force based on the rotational motion of the probe 16, and are sequentially friction stir welded.

[0043] After all the welding points 20 have been welded, the probe 16 is moved away from the welding points 20, thereby completing the friction stir welding method according to this embodiment.

[0044] The rotation speeds of the first and second workpieces 11, 12 and the inner diameter receiving jig 130 can be calculated from the outer diameters of the first and second workpieces 11, 12 near the joining location 20 and the diameter of the inner diameter receiving jig 130. For example, when the outer diameters of the first and second workpieces 11, 12 near the joining location 20 are 288 mm and the diameter of the inner diameter receiving jig 130 is 290 mm, and the rotation speed of the inner diameter receiving jig 130 is 1.0 rpm, the rotation speed of the first and second workpieces 11, 12 can be calculated to be 0.993 rpm.

[0045] Furthermore, when the first workpiece 11 and the second workpiece 12 to be friction stir welded by the friction stir welding apparatus 10, 100 according to the above-described embodiment are fitted together, the end 11c of the first workpiece 11 comes into contact with the step 12d of the second large diameter portion 12c, thereby forming the weld 20. However, the friction stir welding apparatus 10, 100 according to the present invention is capable of friction stir welding welds 20 of various shapes.

[0046] For example, when the cylindrical outer surface of the second member to be joined 12 is fitted so as to be covered by the cylindrical inner surface of the first member to be joined 11, the cylindrical outer surface of the first member to be joined 11 opposite the surface that comes into contact with the second member to be joined 12 becomes the joining point 20.

[0047] Furthermore, for example, by making the inner and outer diameters of the first member to be joined 11 and the second member to be joined 12 substantially the same, the thickness portions of the respective cylinders can be brought into contact with each other to form the joining portion 20.

[0048] It is clear from the claims that such modifications and improvements may also be included within the technical scope of the present invention. [Explanation of symbols]

[0049] 10,100 Friction stir welding apparatus, 11 First welded member, 11a First bottom portion, 11b First diameter portion, 11c End portion, 12 Second welded member, 12a Second bottom portion, 12b Second diameter portion, 12c Second large diameter portion, 12d Step portion, 121b Groove portion, 13,130 Inner diameter receiving jig, 14 Welded member rotation mechanism, 14a Welded member rotation mechanism base portion, 14b Welded member rotation mechanism shaft portion, 14c Welded member rotation mechanism rotation portion, 14d Welded member rotation shaft, 14e Bearing, 15,150 Inner diameter receiving jig rotation mechanism, 15a, 150a Inner diameter receiving jig rotation mechanism base portion, 15b, 150b Inner diameter receiving jig rotation mechanism shaft portion, 15d, 150d Inner diameter receiving jig rotation shaft, 15e, 150e Bearing, 16 probe, 20 joint, 22 clearance, G mounting reference surface.

Claims

1. a hollow cylindrical first member to be joined; a second member to be joined that is hollow and cylindrical and has an inner diameter that is at least approximately the same as or smaller than the inner diameter of the first member to be joined; A friction stir welding apparatus for friction stir welding at a joining point, an inner diameter receiving jig having an outer peripheral surface whose diameter is smaller than the inner diameter of the second workpiece, and supporting at least a part of the cylindrical inner surface of the second workpiece; a workpiece rotation mechanism that rotates the first workpiece and the second workpiece; an inner diameter receiving jig rotation mechanism that allows the inner diameter receiving jig to rotate; a probe that applies a frictional force to the joint by rotating and contacting the joint; Equipped with When the probe is rotated and brought into contact with the joining location while at least a portion of the cylindrical inner surface of the second workpiece is supported by the inner diameter receiving jig, and the first workpiece, the second workpiece, and the inner diameter receiving jig are rotated around a rotation axis that is oriented in a different direction from the rotation axis of the probe, thereby friction stir welding the joining location, Friction stir welding apparatus, characterized in that the rotation axis of the inner diameter receiving jig is eccentric toward the probe side with respect to the rotation axes of the first workpiece and the second workpiece.

2. The friction stir welding apparatus according to claim 1, When the eccentric dimension of the rotation shaft in the inner diameter receiving jig is L and the diameter of the inner diameter receiving jig is R, 0.001≦L / R≦0.005 a rotation axis of the inner diameter receiving jig being eccentric with respect to the rotation axes of the first workpiece and the second workpiece so that the following inequality is satisfied:

3. The friction stir welding apparatus according to claim 1 or 2, The friction stir welding device is characterized in that the inner diameter receiving jig is freely rotated by the inner diameter receiving jig rotation mechanism.

4. The friction stir welding apparatus according to claim 1 or 2, The friction stir welding apparatus is characterized in that the inner diameter receiving jig is rotationally driven by the inner diameter receiving jig rotating mechanism.

5. a hollow cylindrical first member to be joined; a second member to be joined that is hollow and cylindrical and has an inner diameter that is at least approximately the same as or smaller than the inner diameter of the first member to be joined; A friction stir welding method for joining at a joining point, an inner diameter receiving jig having an outer peripheral surface whose diameter is smaller than the inner diameter of the second workpiece, and supporting at least a part of the cylindrical inner surface of the second workpiece; a workpiece rotation mechanism that rotates the first workpiece and the second workpiece; an inner diameter receiving jig rotation mechanism that allows the inner diameter receiving jig to rotate; a probe that applies a frictional force to the joint by rotating and contacting the joint; Using a friction stir welding device equipped with With at least a portion of the cylindrical inner surface of the second workpiece supported by the inner diameter receiving jig, the probe is brought into contact with the joining location while rotating, and the first workpiece, the second workpiece, and the inner diameter receiving jig are rotated around a rotation axis that is oriented in a direction different from the rotation axis of the probe, A friction stir welding method characterized in that the inner diameter receiving jig is rotated while its rotation axis is eccentric toward the probe side relative to the rotation axes of the first workpiece and the second workpiece.

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