Friction stir welding apparatus and friction stir welding method

Abstract

To provide a friction stir welding device and a friction stir welding method which facilitate friction stir welding of a side face of workpiece having a polygonal and curved contour.SOLUTION: A friction stir welding device 1 has a table 3 which has a mounting surface 31 that allows workpiece 9 to be mounted thereon and is rotatable around a table rotation axis C2 crossing the mounting surface 31, a tool holder 10 which is relatively movable in a direction along the mounting surface 31 with respect to the table 3 and is rotatable around a holder rotation axis C1 parallel to the table rotation axis C2, and a joint tool 20 which is supported on the tool holder 10 and rotates around a tool rotation axis crossing the holder rotation axis C1, wherein the control device 40 has a biaxial operation mode of pressing the rotating joint tool 20 against a joint part on the side face of the workpiece 9, rotating the table 3 and relatively moving the joint tool 20 along the joint part, and rotating the tool holder 10 so that the joint tool 20 is directed in a normal direction of the joint part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Friction stir welding is used as a method for joining materials (see Patent Document 1). In Patent Document 1, a friction stir welding device is formed by attaching a dedicated attachment and welding tool to a general-purpose machine tool. In existing friction stir welding devices, for example, a pair of workpieces to be joined are lined up with their top surfaces aligned horizontally, and a joining tool that rotates around an axis perpendicular to the joint between the two is pressed against them, and the workpieces are joined along the joint by friction stirring.

[0003] In the friction stir welding apparatus of Patent Document 1, the welding tool is connected to the spindle of the machine tool to transmit rotational force, and the rotation axis of the welding tool is arranged on the rotation axis of the spindle. In response to this, the present applicant has proposed an L-shaped attachment in which the rotation axis of the joining tool is arranged in a direction intersecting the rotation axis of the main shaft (Patent Application No. 2020-075490). In the proposed L-shaped attachment, the joining tool is driven by an air motor built into the attachment, so that the rotation axis of the joining tool can be positioned in a direction intersecting the main shaft, and the orientation of the attachment or joining tool can be selected by using the rotation of the main shaft. With such an L-shaped attachment, friction stir welding can be performed not only on the horizontal top surface of the workpiece, but also on the vertical side surfaces. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6787764 Summary of the Invention [Problem to be solved by the invention]

[0005] When friction stir welding the side surface of a workpiece using the aforementioned L-shaped attachment, the rotating welding tool is pressed against the side surface of the workpiece in the normal direction, while the L-shaped attachment is moved around the workpiece along the side surface. In this case, if the planar outline of the workpiece is polygonal or curved, it is necessary to rotate the spindle and adjust the orientation of the L-shaped attachment so that the welding tool is always normal to the side surface of the workpiece. In other words, when using an L-shaped attachment to perform friction stir welding on the side of a workpiece with a polygonal or curved contour, it was necessary to control the horizontal position (X-axis and Y-axis planar movement) of the L-shaped attachment according to the contour of the workpiece, as well as control the orientation of the L-shaped attachment (C-axis rotation of the spindle). In particular, the horizontal position of the L-shaped attachment required coordinated control of the X-axis and Y-axis of the machine tool in relation to the curve, which made the control process cumbersome.

[0006] An object of the present invention is to provide a friction stir welding apparatus and a friction stir welding method that can easily perform friction stir welding on the side surfaces of workpieces having polygonal or curved contours. [Means for solving the problem]

[0007] The friction stir welding apparatus of the present invention comprises a table having a workpiece surface on which a workpiece is placed and rotatable about a table rotation axis that intersects with the workpiece surface; a tool holder that is movable relative to the table in a direction along the workpiece surface and that is rotatable about a holder rotation axis that is parallel to the table rotation axis; a welding tool that is supported by the tool holder and rotates about a tool rotation axis that intersects with the holder rotation axis; and a control device that controls operations of the table, the tool holder, and the welding tool, wherein the control device has a biaxial operation mode in which the welding tool is pressed against a welding portion on a side of the workpiece while being rotated, the table is rotated to move the welding tool relatively along the welding portion, and the tool holder is rotated so that the welding tool is oriented in a normal direction to the welding portion.

[0008] In the present invention, the side surfaces of the workpieces can be joined using a joining tool that is supported by a tool holder and rotates around a tool rotation axis that intersects with the holder rotation axis, that is, a joining tool that is attached to a so-called L-shaped tool holder. During welding, the table can be rotated so that the welding area on the side of the workpiece faces the welding tool, simplifying the operation of moving the tool holder along the side of the workpiece. By rotating the tool holder so that the welding tool faces in the normal direction to the welding area, the welding tool can perform appropriate friction stir welding on the workpiece. Therefore, the present invention makes it possible to easily perform friction stir welding on the side surfaces of workpieces having polygonal or curved contours. In addition to the biaxial operation mode in which the table and tool holder are rotated as described above, the control device may also have a uniaxial operation mode in which the table is stopped and the tool holder is rotated while moving along the side surface of the workpiece.

[0009] In the friction stir welding apparatus of the present invention, it is preferable that the control device has a tool rotation control unit that controls the rotation of the welding tool relative to the tool holder, a tool position control unit that controls the position of the tool holder in a direction along the object surface, a tool direction control unit that controls the orientation of the tool holder about the holder rotation axis, a workpiece direction control unit that controls the orientation of the table about the table rotation axis, and a welding control unit that operates the tool rotation control unit, the tool position control unit, the tool direction control unit, and the workpiece direction control unit based on shape information of the workpiece to control the welding operation in the two-axis operation mode.

[0010] In the present invention, a biaxial operation mode is performed according to the shape of the workpiece side surface under the control of the welding control unit. That is, the tool position control unit positions the tool holder at a predetermined position along the load surface, and the workpiece direction control unit rotates the table to orient the workpiece welding portion toward the welding tool on the tool holder. Then, the tool direction control unit rotates the tool holder to orient the welding tool in the normal direction to the welding portion. In this state, the tool rotation control unit appropriately controls the rotation of the welding tool, thereby enabling friction stir welding of the welding portion on the workpiece side surface with the welding tool. During the welding operation, the workpiece direction control unit rotates the table, allowing the welding tool to move sequentially along the welding portion of the workpiece. During this operation, the tool position control unit maintains the welding tool at an appropriate depth relative to the welding portion of the workpiece, and the tool direction control unit adjusts the orientation of the tool holder to always orient the welding tool in the normal direction to the welding portion, thereby maintaining appropriate friction stir welding.

[0011] In the friction stir welding apparatus of the present invention, it is preferable that the table is installed on a machine tool, the tool holder is attached to a spindle of the machine tool, the tool holder can be rotated about the holder rotation axis by rotation of the spindle, the position of the spindle in a direction along the object surface can be adjusted by moving the spindle relative to the table, and the tool holder is installed with a rotation drive unit that rotates the welding tool. In the present invention, the friction stir welding apparatus of the present invention can be realized by using a general-purpose machine tool.

[0012] The friction stir welding method of the present invention is characterized in that it uses a friction stir welding apparatus having a table having a work surface on which a workpiece is placed and rotatable about a table rotation axis that intersects with the work surface, a tool holder that is movable relative to the table in a direction along the work surface and that is rotatable about a holder rotation axis that is parallel to the table rotation axis, and a welding tool that is supported by the tool holder and rotates about a tool rotation axis that intersects with the holder rotation axis, and the method comprises pressing the welding tool against a welding portion on a side of the workpiece while rotating, rotating the table to move the welding tool along the welding portion, and rotating the tool holder so that the welding tool is oriented in a normal direction to the welding portion. According to the friction stir welding method of the present invention, the same effects as those explained in the above-mentioned friction stir welding apparatus can be obtained. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a friction stir welding apparatus and a friction stir welding method that can easily perform friction stir welding on the side surfaces of workpieces having polygonal or curved contours. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a friction stir welding apparatus according to an embodiment of the present invention; [Figure 2] FIG. 3 is a side view showing the tool holder and the joining tool of the embodiment. [Figure 3] FIG. 10 is a perspective view showing the joining operation of the workpiece side surfaces in the embodiment. [Figure 4] FIG. 2 is a block diagram showing a control device according to the embodiment. [Figure 5] FIG. 4 is a plan view showing a uniaxial operation mode for a circular workpiece according to the embodiment. [Figure 6] FIG. 4 is a plan view showing a two-axis operation mode for a circular workpiece according to the embodiment. [Figure 7] FIG. 4 is a plan view showing a two-axis operation mode for a polygonal workpiece according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will now be described with reference to the drawings. 1, a friction stir welding apparatus 1 of this embodiment is configured by attaching an L-shaped tool holder 10 and a friction stir welding tool 20 to a general-purpose machine tool 2 having a vertical spindle. Attaching the welding tool 20 to the friction stir welding attachment 10 forms a friction stir welding head 19.

[0016] The machine tool 2 includes a table 3 having a load surface 31 on which a workpiece 9 is fixed, a spindle 4 to the tip of which a tool can be attached, a spindle head 5 that supports the spindle 4 so that it can rotate freely, and a movement mechanism 6 that moves the spindle head 5 to any position. The table 3, spindle 4, spindle head 5 and moving mechanism 6 are each installed on the top surface of a bed 7, and the whole can be enclosed by a cover 8 that can be opened and closed freely.

[0017] The spindle 4 is supported so as to be rotatable around an axis in the Z-axis direction (holder rotation axis C1), and is driven by a drive motor in the spindle head 5 to rotate (rotational operation Rc1), and can be stopped at a specified angular position. Therefore, the tool holder 10 and the welding tool 20 attached to the tip of the spindle 4 can be set to any orientation by rotation (rotational movement Rc1) around the holder rotation axis C1 by the spindle 4.

[0018] The movement mechanism 6 has a slider 62 supported by a horizontal guide bar 61, and the spindle head 5 is supported by the slider 62 facing downward. By raising and lowering the spindle head 5 relative to the slider 62, the tip of the spindle 4 can be moved to a specified position in the Z-axis direction. Furthermore, by moving the slider 62 along the guide bar 61, the tip of the spindle 4 can be moved to a specified position in the X-axis direction. Furthermore, the movement mechanism 6 has a Y-axis movement mechanism that moves the table 3 in the Y-axis direction, and can move the table 3 and the tip of the spindle 4 relatively to predetermined positions in the Y-axis direction. Therefore, the tool holder 10 attached to the tip of the spindle 4 can be moved relative to the table 3 in the X, Y and Z axial directions by the movement mechanism 6, and the position of the welding tool 20 relative to the workpiece 9 can be adjusted.

[0019] The table 3 has a load surface 31 in a plane direction along the X-axis and Y-axis, and is supported so as to be rotatable about an axis (table rotation axis C2) in the Z-axis direction perpendicular to the load surface 31. The table 3 is driven by a drive motor in the bed 7 to rotate (rotational operation Rc2), and can be stopped at a specified angular position. Therefore, by rotating the table 3 (rotational operation Rc2) while the tool holder 10 and the joining tool 20 attached to the spindle 4 are positioned to the side of the workpiece 9, it is possible to face any part of the workpiece 9 toward the joining tool 20.

[0020] In FIG. 2, the L-shaped tool holder 10 has a main body 11 attached to the spindle 4 of the machine tool 2, a machining shaft 14 that is rotatably supported and has a tip to which a joining tool 20 can be attached, and a rotation drive unit 15 that rotates and drives the machining shaft 14.

[0021] The main body 11 can be attached to the spindle 4 with a standard-based tapered shank 111, and has a center through-hole 112 along its axis, to which center through-hole 112 center air can be supplied from the spindle 4. When the spindle 4 is attached, the axis of the main body 11 is made coaxial with the rotation center of the spindle 4 (holder rotation axis C1). The main body 11 has an extension 113 on the side opposite the tapered shank 111 that extends in a direction intersecting the axis of the main body 11. An extension air passage 114 that communicates with the center through hole 112 is formed in the extension 113, and drive air can be supplied from the center through hole 112 to the rotary drive unit 15 through the extension air passage 114.

[0022] In order to form the L-shaped tool holder 10, the processing shaft 14 on which the joining tool 20 is attached is made rotatable (rotational motion Rc) around an axis (tool rotation axis Cc) perpendicular to the holder rotation axis C1. The tip Tc, which is the processing portion of the welding tool 20 attached to the processing shaft 14, is disposed on the axis of the holder rotation shaft C1. The rotation drive unit 15 has multiple air motors that rotate using driving air supplied from the outside, and by supplying center through air from the main spindle 4 to the rotation drive unit 15 through the center through hole 112, the processing shaft 14 and the joining tool 20 are rotated by the rotation drive unit 15 (rotational operation Rc), and the joining tool 20 can perform friction stir welding on the side surface of the workpiece 9, etc. Furthermore, the direction Di of the welding tool 20 (the direction of the tool rotation axis Cc) can be changed by rotating the tool holder 10 by the spindle 4 (rotational operation Rc1) in accordance with the direction of the side surface of the workpiece 9.

[0023] In such an L-shaped tool holder 10, friction stir welding can be performed on the side surface of the workpiece 9 by the welding tool 20. In Figure 3, when friction stir welding is performed from a start position 94 to an end position 95 on a side surface 93 of a cylindrical workpiece 9, the tool holder 10 is moved along the side surface 93 while the welding tool 20 is rotated, and the orientation Di of the tool holder 10 and the welding tool 20 is changed as the welding tool 20 moves so that the welding tool 20 is perpendicular to the side surface 93.

[0024] First, at position D1, the welding tool 20 is rotated (rotational motion Rc) while being advanced in direction Di, and is pushed into the workpiece 9 at start position 94 to start the welding operation. Then, the welding tool 20 is moved in the advancing direction Dc (position control of the welding tool 20), and when it reaches position D2, the welding tool 20 is retracted, thereby performing friction stir welding from start position 94 to end position 95. At this time, the tool holder 10 is rotated (rotational operation Rc1) by the spindle 4 (orientation control of the welding tool 20) so that the direction Di is perpendicular to the surface of the side surface 93. This allows the welding tool 20 to always be perpendicular to the side surface 93, enabling appropriate friction stir welding of the side surface 93 of the cylindrical workpiece 9.

[0025] Returning to FIG. 1, the machine tool 2 is connected to a control device 40 that uses a computer system. The control device 40 controls the operation of each part of the friction stir welding device 1, including the machine tool 2, and in particular can control the rotation of the spindle 4 (control the orientation of the welding tool 20), the movement of the moving mechanism 6 (control the position of the welding tool 20), and the rotation of the table 3 (control the orientation of the workpiece 9).

[0026] In FIG. 4, the control device 40 has a workpiece shape storage unit 41 that stores shape information of the workpiece 9, and also has a welding control unit 42 that controls the welding operation by the welding tool 20 based on the shape information of the workpiece 9. The welding control unit 42 is connected to a tool rotation control unit 43, a tool position control unit 44, a tool direction control unit 45, and a work direction control unit 46.

[0027] The tool rotation control unit 43 controls the rotation of the welding tool 20 relative to the tool holder 10. Specifically, by controlling the center through air supplied from the spindle 4 to the rotation drive unit 15 of the tool holder 10, the start, stop and rotation speed of the processing axis 14 and the welding tool 20 are controlled.

[0028] The tool position control unit 44 controls the position of the tool holder 10 in a direction along the load surface 31 (horizontal direction including the X-axis and Y-axis). Specifically, the relative positions of the X, Y, and Z axes between the welding tool 20 and the workpiece 9 are adjusted by controlling the movement mechanism 6. In particular, when welding the side surface of the workpiece 9, the welding tool 20 is placed opposite the welding portion on the side surface of the workpiece 9 at the start of the welding operation, and the relative positions of the workpiece 9 and the welding tool 20 are adjusted based on the shape of the side surface of the workpiece 9 (the outline shape of the workpiece 9 in a plan view) during the welding operation.

[0029] The tool direction control unit 45 controls the orientation of the tool holder 10 around the holder rotation axis C1. Specifically, based on the current position of the tool holder 10, the current angular position of the table 3, and the side shape of the workpiece 9, the spindle 4 is rotated so that the orientation Di of the joining tool 20 is perpendicular to the welding portion on the side surface of the workpiece 9.

[0030] The workpiece direction control unit 46 controls the orientation of the table 3 around the table rotation axis C2. Specifically, based on the current position of the tool holder 10, the current angular position of the table 3, and the side shape of the workpiece 9, the table 3 is rotated so that the welding portion on the side surface of the workpiece 9 faces the joining tool 20.

[0031] The joining control unit 42 operates the tool rotation control unit 43, the tool position control unit 44, the tool direction control unit 45, and the work direction control unit 46 based on the shape information of the workpiece 9 stored in the workpiece shape memory unit 41, and performs the joining operation of the side surface of the workpiece 9 using the joining tool 20. The joining control unit 42 has a control procedure for the joining operation of the side surface of the workpiece 9 by the joining tool 20, which includes a uniaxial operation mode in which the tool holder 10 is moved and rotated along the side surface of the workpiece 9 while the table 3 is fixed, and a biaxial operation mode in which the tool holder 10 and the table 3 are each rotated.

[0032] In FIG. 5, in the single-axis operation mode, the table 3 is kept stationary and the tool holder 10 is moved along the side surface of the workpiece 9. Prior to the welding operation, with the table 3 fixed in a fixed position, the workpiece 9 is placed on the load surface 31 of the table 3. Next, the welding control unit 42 operates the moving mechanism 6 using the tool position control unit 44 to move the tool holder 10 and place it at position D1 on the side of the workpiece 9, and then rotates the spindle 4 using the tool direction control unit 45 to position the tip of the welding tool 20 facing the side of the workpiece 9.

[0033] During the joining operation, the tool rotation control unit 43 operates the rotation drive unit 15 to rotate the joining tool 20 and join the side surface of the workpiece 9, while the tool position control unit 44 operates the moving mechanism 6 to move the tool holder 10 from position D1 to position D2. During movement, the tool position control unit 44 performs coordinated control of the movement Mx of the tool holder 10 in the X-axis direction and the movement My of the tool holder 10 in the Y-axis direction, thereby moving the tip of the welding tool 20 along the side surface of the workpiece 9. At the same time, under the control of the tool direction control unit 45, the tool holder 10 is rotated Rc1 about the holder rotation axis C1, so that the welding tool 20 is maintained in a direction perpendicular to the welding portion on the side surface of the workpiece 9. As a result, a welding mark is formed on the side surface of the workpiece 9, extending horizontally from position D1 to position D2.

[0034] In contrast to this single-axis operation mode, in the two-axis operation mode, the welding tool 20 is pressed against the welding portion on the side of the workpiece 9 while being rotated, the table 3 is rotated to move the welding tool 20 relatively along the welding portion, and the tool holder 10 is rotated so that the welding tool 20 faces in the normal direction of the welding portion.

[0035] In FIG. 6, in the two-axis operation mode, when the contour of the workpiece 9 is circular and the center is on the table rotation axis C2, the tool holder 10 is set at a fixed position and the tool holder 10 and the table 3 are each rotated. Prior to the welding operation, with the table 3 fixed in a fixed position, the workpiece 9 is placed on the load surface 31 of the table 3. Next, the welding control unit 42 operates the moving mechanism 6 using the tool position control unit 44 to move the tool holder 10 and place it at position D1 on the side of the workpiece 9, and then rotates the spindle 4 using the tool direction control unit 45 to position the tip of the welding tool 20 opposite the side of the workpiece 9.

[0036] During the joining operation, the tool rotation control unit 43 operates the rotation drive unit 15 to rotate the joining tool 20 and join the side surface of the workpiece 9, while the workpiece direction control unit 46 operates the table 3, and the tool holder 10 is moved relative to the workpiece 9 from position D1 to position D2 by the rotational movement Rc2 of the table 3 around the table rotation axis C2. During the relative movement, the tool direction control unit 45 rotates the spindle 4, and the joining tool 20 is maintained in a direction perpendicular to the welding portion on the side of the workpiece 9 by the rotation Rc1 of the tool holder 10 about the holder rotation axis C1. As a result, a welding mark is formed on the side surface of the workpiece 9, extending horizontally from position D1 to position D2. The relative movement between the tool holder 10 and the workpiece 9 is performed by the rotation operation Rc2 of the table 3, during which the tool position control unit 44 basically does not move the tool holder 10. However, if the center of the workpiece 9 is misaligned with the table rotation axis C2 or if the side of the workpiece 9 is uneven, the tip of the joining tool 20 may be made to follow the side of the workpiece 9 by movement My in the Y-axis direction.

[0037] In FIG. 7, in the two-axis operation mode, if the outline of the workpiece 9 in a plan view is not circular, such as a polygonal shape, or if the workpiece 9 is circular but its center is offset from the table rotation axis C2, the tool holder 10 and the table 3 are rotated, and an operation is performed to move the tool holder 10 closer to or farther away from the workpiece 9. Prior to the welding operation, with the table 3 fixed in a fixed position, the workpiece 9 is placed on the load surface 31 of the table 3. Next, the welding control unit 42 operates the moving mechanism 6 using the tool position control unit 44 to move the tool holder 10 and place it at position D1 on the side of the workpiece 9, and then rotates the spindle 4 using the tool direction control unit 45 to position the tip of the welding tool 20 opposite the side of the workpiece 9.

[0038] During the joining operation, the tool rotation control unit 43 operates the rotation drive unit 15 to rotate the joining tool 20 and join the side surface of the workpiece 9, while the workpiece direction control unit 46 operates the table 3, and the tool holder 10 is moved relative to the workpiece 9 from position D1 to position D2 by the rotational movement Rc2 of the table 3 around the table rotation axis C2. During the relative movement, the tool position control unit 44 causes the movement mechanism 6 to move the tool holder 10 in the Y-axis direction My in accordance with the distance from the table rotation axis C2 of the portion of the side surface of the workpiece 9 to be joined by the welding tool 20, thereby holding the tip of the welding tool 20 at an appropriate depth relative to the side surface of the workpiece 9. At the same time, the tool direction control unit 45 rotates the spindle 4, and the tool holder 10 is rotated Rc1 about the holder rotation axis C1, thereby holding the welding tool 20 in a direction perpendicular to the welding portion on the side surface of the workpiece 9.

[0039] As the welding operation progresses, the workpiece 9 rotates around the table rotation axis C2, changing the distance between the side of the workpiece 9 and the table rotation axis C2. In response to this change, the tool position control unit 44 moves the moving mechanism 6 in the Y-axis direction My, and at the same time, the tool direction control unit 45 rotates the joining tool 20 around the holder rotation axis C1 Rc1, so that the joining tool 20 is kept in an appropriate position relative to the side of the workpiece 9 and appropriate joining is performed. As a result, a welding mark is formed on the side surface of the workpiece 9, extending horizontally from position D1 to position D2.

[0040] According to the friction stir welding apparatus 1 of this embodiment, the following effects can be obtained. In this embodiment, the side surface of the workpiece 9 can be joined by a joining tool 20 that is supported by the tool holder 10 and rotates around a tool rotation axis Cc that intersects with the holder rotation axis C1, that is, a joining tool 20 attached to a so-called L-shaped tool holder 10. During welding, the welding portion on the side of the workpiece 9 can be faced toward the welding tool 20 by rotating the table 3, which simplifies the operation of moving the tool holder 10 along the side of the workpiece 9. At this time, by rotating the tool holder 10 so that the welding tool 20 faces in the normal direction of the welding portion, the welding tool 20 can perform appropriate friction stir welding on the workpiece 9. Therefore, this embodiment makes it possible to easily perform friction stir welding on the side surfaces of the workpiece 9, including those having polygonal or curved contours.

[0041] In this embodiment, under the control of the joining control unit 42, an operation in a biaxial operation mode can be performed according to the shape of the side surface of the workpiece 9 (the contour shape of the workpiece 9 in a plan view). That is, the tool position control unit 44 positions the tool holder 10 at a predetermined position in a direction along the load surface 31, and the workpiece direction control unit 46 rotates the table 3 so that the welding portion of the workpiece 9 faces the welding tool 20 of the tool holder 10. Then, the tool direction control unit 45 rotates the tool holder 10 so that the welding tool 20 faces the normal direction of the welding portion. In this state, by appropriately controlling the rotation of the welding tool 20 using the tool rotation control unit 43, friction stir welding can be performed on the welding portion on the side of the workpiece 9 by the welding tool 20. During the welding operation, the workpiece direction control unit 46 rotates the table 3, thereby allowing the welding tool 20 to move sequentially along the welding portion of the workpiece 9. At this time, the tool position control unit 44 maintains the welding tool 20 at an appropriate depth relative to the welding portion of the workpiece 9, and the tool direction control unit 45 adjusts the orientation of the tool holder 10 so that the welding tool 20 is always oriented in the normal direction to the welding portion, thereby maintaining appropriate friction stir welding.

[0042] In this embodiment, the table 3 is installed in a machine tool 2, the tool holder 10 is attached to a spindle 4 of the machine tool 2, the tool holder 10 can rotate about the holder rotation axis C1 by rotating the spindle 4, the position of the tool holder 10 in the directions along the workpiece surface 31 (X-axis direction and Y-axis direction) can be adjusted by moving the spindle 4 relative to the table 3, and a rotation drive unit 15 that rotates the welding tool 20 is installed in the tool holder 10. Therefore, the friction stir welding apparatus 1 can be realized by using a general-purpose machine tool 2.

[0043] The present invention is not limited to the above-described embodiment, and includes modifications within the scope of achieving the object of the present invention. In the above embodiment, the control device 40 can select between a single-axis operation mode (see FIG. 5) and a two-axis operation mode (see FIGS. 6 and 7). However, the control device 40 may be configured to operate only in the two-axis operation mode, and the welding area may always be advanced by rotating the table 3 around the table rotation axis C2. In the above embodiment, the welding path on the side of the workpiece 9 is constant in the Z-axis direction, but if the welding path on the side of the workpiece 9 changes in the Z-axis direction, the Z-axis position of the joining tool 20 can be adjusted by the moving mechanism 6 as the joining tool 20 progresses in the welding area.

[0044] In the above embodiment, a machine tool 2 is used in which the load surface 31 of the table 3 is horizontal (X-axis and Y-axis) and the main spindle 4 is arranged along the vertical Z-axis, but a machine tool in which the load surface 31 of the table 3 is vertical and the main spindle 4 extends horizontally may also be used. In the above embodiment, the coordinated operation in the two-axis operation mode is the holder rotation axis C1 and the table rotation axis C2 (both of which are C-axis rotations around the vertical Z axis), but these may also be rotation axes A1, A2 around the X axis or rotation axes B1, B2 around the Y axis. The friction stir welding apparatus 1 of the above embodiment is configured to weld the side surface of the workpiece 9 by attaching an L-shaped tool holder 10 to the machine tool 2, but it is also possible to weld the top surface of the workpiece 9 by removing the L-shaped tool holder 10 and replacing it with a straight-type tool holder. [Industrial Applicability]

[0045] The present invention can be used in a friction stir welding apparatus and a friction stir welding method. [Explanation of symbols]

[0046] 1...Friction stir welding device, 2...Machine tool, 3...Table, 31...Load surface, 4...Spindle, 5...Spindle head, 6...Moving mechanism, 61...Guide bar, 62...Slider, 7...Bed, 8...Cover, 9...Workpiece, 93...Side, 94...Start position, 95...End position, 10...Tool holder, 11...Main body, 111...Tapered shank, 112...Center through hole, 113...Extension part, 114...Extension air passage, 14...Processing axis, 15...Rotation drive part, 20...Welding tool, 40...Control device, 41 ...Workpiece shape memory unit, 42...Joining control unit, 43...Tool rotation control unit, 44...Tool position control unit, 45...Tool direction control unit, 46...Workpiece direction control unit, C1...Holder rotation axis, C2...Table rotation axis, Cc...Tool rotation axis, D1...Position, D2...Position, Dc...Progression direction, Di...Orientation of joining tool, Mx...Movement in X-axis direction, My...Movement in Y-axis direction, Rc...Rotational movement, Rc1...Rotational movement of tool holder, Rc2...Rotational movement of table, Tc...Tip of joining tool.

Claims

1. a table having a workpiece surface on which a workpiece having a polygonal outline in a plan view is placed and rotatable around a table rotation axis intersecting the workpiece surface; a tool holder that is movable relative to the table in a direction along the object plane and that is rotatable around a holder rotation axis that is parallel to the table rotation axis; a welding tool supported by the tool holder, rotatable around a tool rotation axis intersecting the holder rotation axis, and having a processing portion at a tip end disposed on the axis line of the holder rotation axis; a control device that controls the operations of the table, the tool holder, and the welding tool, the control device has a biaxial operation mode in which the control device presses the rotating welding tool against a welding portion on a side surface of the workpiece, rotates the table to move the welding tool relatively along the welding portion, rotates the tool holder so that the welding tool is oriented in a normal direction to the welding portion, and moves the tool holder relatively to the table in a direction along the object surface in accordance with a distance from the table rotation axis of the welding portion.

2. The control device a tool rotation control unit that controls rotation of the welding tool relative to the tool holder; a tool position control unit that controls a position of the tool holder in a direction along the object plane; a tool direction control unit that controls the orientation of the tool holder around the holder rotation axis; a workpiece direction control unit that controls the orientation of the table around the table rotation axis; 2. The friction stir welding apparatus according to claim 1, further comprising: a welding control unit that controls the welding operation in the biaxial operation mode by operating the tool rotation control unit, the tool position control unit, the tool direction control unit, and the workpiece direction control unit based on shape information of the workpiece.

3. The table is installed in a machine tool, the tool holder is attached to a spindle of the machine tool, and is capable of rotating about the holder rotation axis by rotation of the spindle, and its position in a direction along the object plane is adjustable by movement of the spindle relative to the table, The tool holder is provided with a rotation drive unit that rotates the welding tool.

3. The friction stir welding apparatus according to claim 1 or 2.

4. a table having a workpiece surface on which a workpiece having a polygonal outline in a plan view is placed and rotatable around a table rotation axis intersecting the workpiece surface; a tool holder that is movable relative to the table in a direction along the object plane and that is rotatable around a holder rotation axis that is parallel to the table rotation axis; a welding tool supported by the tool holder, rotatable around a tool rotation axis intersecting with the holder rotation axis, and having a processing portion at a tip end disposed on the axis line of the holder rotation axis, a friction stir welding method comprising: pressing the rotating welding tool against a welding portion on a side surface of the workpiece; rotating the table to move the welding tool along the welding portion; rotating the tool holder so that the welding tool is oriented in a normal direction to the welding portion; and moving the tool holder relative to the table in a direction along the object surface in accordance with a distance from the table rotation axis of the welding portion.

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