Rotation tool, joining device and joining method

Abstract

To provide a rotation tool which enables load control to be performed in a state where the rotation tool is attached to a machining center, and to provide a joint device and a joint method.SOLUTION: A rotation tool includes: a body 10 having a fixed part 11 and a rotary shaft 12; a stirring pin 50 which is disposed in the body 10 so as to be rotatable and movable in an axial direction of the rotary shaft 12 and inserted into a member to be joined (a joined member) 2 to stir frictionally; and a shoulder 60 which is formed separately from the stirring pin 50 and provided in the body 10 in a manner that the shoulder 60 can move in the axial direction of the rotary shaft 12 without receiving rotational force from the body 10 and which presses the joined member 2 while contacting with the joined member 2. The stirring pin 50 and the shoulder 60 are attached so as to be rotatable relative to each other and integrally move in the axial direction of the rotary shaft 12 to form an assembly 70. The rotation tool further includes a first elastic member 51 which biases the assembly 70 to a tip side of the stirring pin 50 in the axial direction of the rotary shaft 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotary tool, a welding apparatus, and a welding method used in friction stir welding. [Background technology]

[0002] Known welding devices for performing friction stir welding include those that perform load control and those that perform position control in order to control the amount of thrust of a rotary tool into workpieces to be welded. Load control is mainly used in welding devices that use a robot (robot arm), and position control is mainly used in welding devices that use a machining center (MC).

[0003] An example of a welding device that controls load is disclosed in Patent Document 1. The welding device of Patent Document 1 controls the press-in depth of the shoulder member or the pin member into the workpieces to obtain good welding quality with suitable accuracy according to the welding conditions. In order to control the press-in depth, the welding device controls the relative position of the pin member with respect to the shoulder member based on a press-in reference point set by a press-in reference point setting unit. In order to perform the above control, the welding device is equipped with a pressing force detection unit, a pressure reference point setting unit, a tool drive control unit, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-196681 A Summary of the Invention [Problem to be solved by the invention]

[0005] The welding device of Patent Document 1 has a complex structure and is expensive because it performs load control, so in recent years there has been a demand for a rotary tool that can be attached to a relatively inexpensive MC that can only perform position control and that can also perform load control.

[0006] From this viewpoint, an object of the present invention is to provide a rotary tool, a welding device, and a welding method that enable load control in a state where the tool is mounted on a machining center. [Means for solving the problem]

[0007] The present invention relates to a rotary tool used in a welding device for friction stir welding of workpieces, the rotary tool comprising: a main body having a fixing portion attached and fixed to the welding device and a rotating shaft for transmitting a rotational force from the welding device; a stirring pin disposed on the main body so as to be rotatable by receiving a rotational force from the main body and movable in an axial direction of the rotating shaft, the stirring pin being inserted into the workpieces to perform friction stirring on the workpieces; and a shoulder configured separately from the stirring pin, not receiving a rotational force from the main body, and provided on the main body so as to be movable in the axial direction of the rotating shaft, the shoulder pressing the workpieces in a state of contact with the workpieces, the stirring pin and the shoulder being attached to the main body so as to be rotatable relative to each other and to move integrally in the axial direction of the rotating shaft to form an assembly, and the stirring pin and the shoulder further comprising a first elastic member for biasing the assembly toward a tip side of the stirring pin in the axial direction of the rotating shaft. the main body further includes a cylindrical holder attached to the rotating shaft, and a slide shaft that is accommodated in the center of the holder so as to be slidable in the direction of the rotating shaft and rotates synchronously with the holder, the assembly is provided at the tip of the slide shaft, and the slide shaft is biased toward the tip side of the assembly via the first elastic member, and the first elastic member is accommodated inside the holder and disposed between the base end of the slide shaft and the fixed portion side of the holder. The rotary tool is characterized by the above. In the rotary tool of the present invention, it is preferable that the first elastic member is interposed between the assembly and the main body portion.

[0011] In the rotary tool of the present invention, it is preferable that a long, groove-shaped key groove is formed in the axial direction of the rotation shaft in one of the holder and the slide shaft, and a key is formed in the other of the holder and the slide shaft, the key being oriented in a direction intersecting the axial direction of the rotation shaft and fitting into the key groove, and as the slide shaft moves in the axial direction of the rotation shaft, the key moves inside the key groove along the axial direction of the rotation shaft, and as the holder rotates, the key and the key groove come into contact circumferentially, thereby causing the holder and the slide shaft to rotate synchronously.

[0012] In the rotary tool of the present invention, a bearing is preferably interposed between the shoulder and the stirring pin.

[0013] The rotary tool of the present invention preferably further comprises a second elastic member which biases the shoulder toward the tip side of the stirring pin in the axial direction of the rotary shaft.

[0014] The rotary tool of the present invention preferably further comprises a holding portion for holding the shoulder in a non-rotating state.

[0015] In the rotary tool of the present invention, the first elastic member is preferably an elastic member that imparts elastic force by at least one selected from a solid spring, a fluid spring, a magnetic force, and an electromagnetic force. In the rotary tool of the present invention, an extension portion is formed at the upper end of the slide shaft, which is extended in a columnar shape toward the upper end side, and it is preferable that the elastic member surrounds the extension portion and is attached between the extension portion and the fixed portion side of the holder.

[0016] The second invention is as set forth in claims 1 to 5. 8 a power means for outputting a rotational force to be transmitted to the rotation shaft of the rotary tool, and a position control means for holding the fixed portion of the rotary tool and controlling a position of the rotary tool, wherein the rotary tool is moved to a predetermined height position relative to the workpieces by the position control means, and the stirring pin is inserted into the workpieces while pressing the shoulder against the workpieces, thereby performing friction stir welding of the workpieces.

[0017] The joining device of the present invention preferably further comprises a holding portion for holding the shoulder in a non-rotating state.

[0018] The third invention is as set forth in claims 1 to 5. 8a rotating tool according to any one of claims 1 to 5, wherein the rotating tool is moved to a predetermined height position relative to the workpieces, and the rotating stirring pin is inserted into the workpieces while pressing the shoulder against the workpieces, thereby performing friction stir welding on the workpieces.

[0019] According to the welding apparatus and welding method of the present invention, similarly to the rotary tool of claim 1, even when a machining center is used, pseudo load control becomes possible and the surface finish after friction stir welding becomes good. Effect of the Invention

[0020] According to the rotary tool, welding apparatus, and welding method of the present invention, it is possible to perform load control by utilizing an elastic member. [Brief description of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view showing a rotary tool according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a rotation tool according to the embodiment. [Diagram 3] FIG. 2 is an exploded perspective view showing a rotation tool according to an embodiment. [Figure 4] 5A to 5C are cross-sectional views showing the operation of each part of the rotary tool according to the embodiment during friction stir welding. [Diagram 5] FIG. 13 is a perspective view showing a modified example of the holding portion of the rotation tool according to the embodiment. [Figure 6] 11 is a cross-sectional view showing a modified example of a shoulder of the rotation tool according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The embodiments of the present invention will be described with reference to the drawings as appropriate. The present invention is not limited to the following embodiments. In addition, some or all of the components in the embodiments can be combined as appropriate. Furthermore, the drawings are intended to conceptually explain the present invention, and the dimensions and ratios of each component shown may differ from the actual ones.

[0023] [1. Rotation tool] First, the configuration of the rotation tool according to this embodiment will be described. As shown in Fig. 1, the rotation tool 1 according to this embodiment is used in a welding device 3 (see Fig. 1) that performs friction stir welding of workpieces 2 (see Fig. 4), and is inserted into the butted portions of the workpieces 2 while rotating. The rotation tool 1 includes a main body 10, a stirring pin 50, a shoulder 60, and a first elastic member 51. The stirring pin 50 and the shoulder 60 are attached so as to be relatively rotatable and to move integrally in the axial direction of a rotating shaft, thereby configuring an assembly 70. The rotation tool 1 also includes a holding portion 80.

[0024] <Main body> The main body 10 is a part fixed to a joining device 3 such as a machining center, and includes a fixed part 11 and a rotating shaft 12. The fixed part 11 is a part attached to and fixed to the joining device 3, and has a cylindrical shape. The fixed part 11 is a chuck mechanism, and can detachably fix the fixed part 11 to the joining device by cooperating with a mating chuck mechanism provided on the joining device 3. The chuck mechanism can be, for example, a groove provided on the fixed part 11 and a claw provided on the joining device 3 that fits into the groove on the fixed part 11 side and clamps it. A rotating shaft 12 is connected to the other end side (lower side in FIG. 1) of the fixed part 11 from the side attached to the joining device 3. The rotating shaft 12 has a cylindrical shape. The rotating shaft 12 is a part that transmits a rotational force from the joining device 3 to the stirring pin 50, and is connected to a rotating shaft (not shown) of the joining device 3 via the fixed part 11.

[0025] As also shown in FIG. 2 and FIG. 3, the main body 10 further includes a holder 21 and a slide shaft 31.

[0026] <Holder> The holder 21 is attached to the rotating shaft 12, rotates synchronously with the rotating shaft 12, and supports the slide shaft 31 and the stirring pin 50. The holder 21 has a cylindrical shape with a closed top and a bottom, and the internal hollow portion serves as a storage recess 22 into which the slide shaft 31 is inserted. The storage recess 22 has a cylindrical shape and is open on both sides in the axial direction of the rotating shaft 12 (both the top and bottom in FIG. 1). A key groove 23 is formed in the cylindrical body of the holder 21. The key groove 23 is formed in a long oval shape along the axial direction of the rotating shaft 12 (the up and down direction in FIG. 1), and penetrates from the outer peripheral surface to the inner peripheral surface of the holder 21. The key groove 23 does not have to penetrate the cylindrical body, and may be formed in a groove shape on the inner peripheral surface of the cylindrical body. The key grooves 23 are arranged at 180° intervals in the circumferential direction of the cylindrical body, and are formed in two places facing each other. The number of key grooves 23 is not limited to two, but may be one, or three or more.

[0027] <Slide shaft> The slide shaft 31 is housed in the storage recess 22 at the center of the holder 21 so as to be slidable in the rotation axis direction (up and down direction in FIG. 1), and rotates synchronously (together) with the holder 21. The slide shaft 31 has a cylindrical shape and has an outer diameter that allows it to be housed in the storage recess 22. A key 32 that protrudes outward is provided on the outer circumferential surface of the slide shaft 31. The key 32 is fixed at a position corresponding to the key groove 23 at the base end (end on the side of the rotation shaft 12: upper end in FIG. 1) of the slide shaft 31, and is inserted into the key groove 23. The key 32 has an oval shape that is long in the rotation axis direction, and has a width dimension equal to that of the key groove 23 and a length dimension shorter than the longitudinal dimension of the key groove 23. In other words, the key 32 fits into the width direction of the key groove 23 and is movable in the longitudinal direction. The shape of the key 32 is not limited to an oval shape, and may be other shapes such as a circle, an ellipse, an oblong, or a rectangle, so long as it has a width dimension equivalent to that of the key groove 23. A stirring pin 50 is integrally provided at the tip end of the slide shaft 31 (the end on the side away from the joining device 3: the lower end in FIG. 1). Therefore, the stirring pin 50 is biased toward the tip end side of the slide shaft 31 (the side away from the joining device 3: the lower side in FIG. 1) by being biased toward the tip end side by the first elastic member 51.

[0028] <Agitating pin> The stirring pin 50 is a part that receives a rotational force from the main body 10, rotates and is inserted into the workpiece 2, and performs friction stirring on the workpiece 2. The stirring pin 50 is formed, for example, from tool steel in a cylindrical shape. The tip 52 (lower end in FIG. 1) of the stirring pin 50 tapers toward the tip. The tip of the tip 52 of the stirring pin has a flat surface perpendicular to the axial direction. An enlarged flange 53 is integrally formed at the base end of the stirring pin 50. The flange 53 is integrally formed with the slide shaft 31, and the stirring pin 50 and the flange 53 move in the axial direction of the rotation shaft by the sliding movement of the slide shaft 31. The flange 53 has a larger diameter than the slide shaft 31, and a ring-shaped step 54 is formed at the connection part (base end of the flange 53) between the flange 53 and the slide shaft 31 in a plan view. The flange 53 functions as a receiving part that receives the elastic force of the first elastic member 51 from the rear end side (the side closer to the joining device 3: the upper side in FIG. 1) of the slide shaft 31. The flange 53 also functions as a supporting part that supports the shoulder 60 provided on the tip side (the lower side in FIG. 1) of the stirring pin 50.

[0029] <Shoulder> The shoulder 60 is a portion that presses the workpieces in contact with the workpieces. The shoulder 60 is constructed separately from the stirring pin 50, and is provided so as to be rotatable relative to the stirring pin 50, so as not to receive a rotational force from the main body 10. The shoulder 60 is immovable relative to the axial direction of the stirring pin 50 and the rotating shaft 12, and moves in the axial direction together with the stirring pin 50. That is, the shoulder 60 is movable in the axial direction relative to the holder 21. Specifically, the shoulder 60 is formed of, for example, tool steel. The shoulder 60 has a cylindrical shape, and is arranged coaxially so as to surround the stirring pin 50. That is, the stirring pin 50 is inserted into the hollow portion 61 of the shoulder 60. The base end (upper end in FIG. 1) of the hollow portion 61 has an expanded diameter, and a bearing 63 is inserted between the stirring pin 50 and the shoulder 60. The bearing 63 is arranged so as to surround the stirring pin 50. This allows the shoulder 60 to rotate relatively to the stirring pin 50 but prevents it from moving axially relative to the stirring pin 50 .

[0030] The tip surface of the shoulder 60 is flush with the base end of the tapered surface of the tip portion 52 of the stirring pin 50. In other words, the tip portion 52 of the stirring pin 50 protrudes toward the tip side from the tip surface of the shoulder 60. The shoulder 60 moves in the axial direction of the rotating shaft 12 together with the stirring pin 50, which is integrally connected to the slide shaft 31, as the slide shaft 31 slides.

[0031] As described above, the stirring pin 50 and the shoulder 60 are integrated to form the assembly 70 that moves together in the axial direction of the rotating shaft 12. In other words, the assembly 70 is provided at the tip of the slide shaft 31.

[0032] <First elastic member> The first elastic member 51 is a portion that biases the assembly 70, which includes the stirring pin 50 and the shoulder 60, toward the tip side in the axial direction of the rotating shaft. The first elastic member 51 is, for example, configured of a coil spring, and is disposed so as to surround the outer peripheral surface of the lower part of the slide shaft 31. The first elastic member 51 is attached between the flange portion 53 of the assembly 70 and the tip of the holder 21. The first elastic member 51 is configured to bias the assembly 70 toward the tip side in response to a force received from the assembly 70 side.

[0033] The elasticity of the first elastic member 51 is set so that when the stirring pin 50 is inserted with a predetermined pushing load into the workpiece 2 made of at least one material selected from the group consisting of aluminum, copper, magnesium, and alloys thereof, the stirring pin 50 is displaced and inserted within a predetermined range within the total movable range of the stirring pin 50 by the first elastic member 51 (the movable length of the key 32 in the key groove 23). For example, when the first elastic member 51 is a coiled kneading spring, when the first elastic member 51 is inserted with a load of 100 kg to 5 t, the stirring pin 50 is inserted into the workpiece 2 in a state in which the deflection amount of the first elastic member 51 is deformed in a range of 0 to 30% with respect to the free length of the first elastic member 51, and the shoulder 60 presses the workpiece 2. As a result, when the stirring pin 50 is pushed into the workpiece 2 at a constant height, even if the height of the workpiece 2 changes, the first elastic member 51 deforms according to the change in the workpiece, making it easier to keep the insertion amount of the stirring pin 50 constant.

[0034] The first elastic member 51 is not limited to a coil spring, and may be a metal spring such as a leaf spring or a disc spring, or a polymeric elastic body (elastomer) such as rubber, polymeric resin, sponge-like resin, etc. Furthermore, the first elastic member 51 may be a fluid spring using air pressure, gas pressure, or hydraulic pressure, or a magnetic spring using magnetic force or electromagnetic force.

[0035] The first elastic member 51 may be set in consideration of the joining conditions so as to satisfy the relationship between the deformation amount and the elastic modulus when the stirring pin 50 is inserted to a predetermined depth. In addition, the first elastic member 51 may be set in consideration of the joining conditions so as to satisfy the relationship between the deformation amount and the elastic modulus when the shoulder 60 pressed against the workpiece 2 is in contact with the workpiece 2 and is not inserted into the workpiece 2 and can hold down the workpiece 2. Examples of joining conditions that affect the setting of the first elastic member 51 include the conditions of the workpiece 2, such as the material of the workpiece 2 and the shape of the joint, and the joining mode, such as the insertion depth of the stirring pin 50, the shape of the rotating tool 1, the rotation speed, and the movement speed. Note that the shoulder 60 only needs to be at least partially in contact with the workpiece 2, and some space may be generated between the workpiece 2 and the shoulder 60 depending on the relationship with the surface shape of the workpiece 2, but it is preferable that the shoulder 60 contacts the workpiece 2 without any gaps so that the metal material overflowing due to friction stir welding can be held down to prevent the generation of burrs. Furthermore, the shoulder 60 may be inserted somewhat into the workpieces 2, but it is preferable that it is not inserted deeply into the workpieces 2 so that a recess is not formed due to contact between the workpieces 2 and the shoulder 60 after joining.

[0036] <Holding part> As shown in FIG. 2, the holding part 80 is a rod-like arm-like member, and its tip is fixed to the outer circumferential surface of the shoulder 60. The base end of the holding part 80 is connected to a fixed system on the joining device 3 side, and is configured to hold the shoulder 60 in a non-rotating state. This holding part 80 is included in the rotating tool 1. The shoulder 60 is provided so as to be rotatable relative to the rotating shaft 12, the first holder 21, and the stirring pin 50, and is further held in a non-rotating state by the holding part 80. As a result, even when the stirring pin 50 rotates, the shoulder 70 can be held in a non-rotating state.

[0037] [2.Joining device] Next, the configuration of a welding device 3 equipped with the rotary tool 1 having the above-mentioned configuration will be described. The welding device 3 includes a power means (not shown) that outputs a rotational force to be transmitted to the rotary shaft 12 of the rotary tool 1, and a position control means (not shown) that holds the fixed part 11 of the rotary tool 1 and controls the position of the rotary tool. The welding device 3 is configured, for example, by a machining center that performs position control, and the position control device is configured by a CPU or the like, and operates the power means to move the rotary tool 1 based on position information input in advance. The power means moves the rotary tool 1 in three axial directions of X, Y and Z.

[0038] [3.Joining method] Next, a joining method according to the present invention will be described with reference to Fig. 4. In this joining method, the rotary tool 1 of this embodiment is moved to a predetermined height position set in advance relative to the workpieces 2, and while pressing the shoulder 60 of the rotary tool 1 against the workpieces 2, the stirring pin 50 of the rotary tool 1 is inserted into the workpieces 2 to perform friction stir welding of the workpieces 2.

[0039] When inserting the stirring pin 50, as the rotating tool 1 is moved toward the workpieces 2 in the insertion direction, first the tip of the stirring pin 50 comes into contact with the workpieces 2. As the rotating tool 1 is moved further toward the workpieces 2, the first elastic member 51 is compressed, and the stirring pin 50 is inserted into the workpieces 2 while the elastic force of the first elastic member 51 urging the stirring pin 50 toward the workpieces 2 increases. As the rotating tool 1 is moved further toward the workpieces 2, the shoulder 60 comes into contact with the workpieces 2. As the first elastic member 51 is compressed, the elastic force of the first elastic member 51 urging the stirring pin 50 and the shoulder 60 toward the workpieces 2 increases, and the shoulder 60 is pressed against the workpieces. At this time, the first elastic member 51 is not completely deformed and has some residual force due to the deformation of the first elastic member 51, and the stirring pin 50 is inserted into the workpieces 2 and the shoulder 60 is set so that it can press the workpieces 2. Also, the first elastic member 51 is set so that the shoulder 60 can press the workpieces 2 while in contact with the workpieces 2 without being inserted into the workpieces 2.

[0040] During welding by the rotary tool 1, as shown on the left side in Fig. 4, an assembly 70 including a stirring pin 50 and a shoulder 60 is biased toward the tip side by a first elastic member 51. As a result, if there is no error in the height of the workpieces 2 with respect to the set value, the tip 52 of the stirring pin 50 is pressed into the workpieces 2 to the desired depth, as shown on the left side in Fig. 4. In addition, the shoulder 60 is capable of pressing down the workpieces 2 while in contact with the workpieces 2, without being inserted into the workpieces 2.

[0041] Next, as shown in the center of FIG. 4, a case will be described in which the height of the workpieces 2 becomes slightly higher than the set value due to an error while friction stir welding is being performed. Here, if the first elastic member 51 is not present and the stirring pin 50 is simply pushed into the workpieces 2, the insertion amount of the stirring pin 50 and the shoulder 60 becomes larger by the amount of increase in the height of the workpieces 2 compared to the case in which there is no error in the height of the workpieces 2 relative to the set value. In contrast, when welding is performed using the rotary tool 1 of this embodiment, the assembly 70 including the stirring pin 50 is pushed up by the upward reaction force from the workpieces 2 due to the increase in the height of the workpieces 2, and the first elastic member 51 is compressed by this pushing up, and the assembly 70 is pushed down by the downward elastic force from the first elastic member 51. The positions of the stirring pin 50 and the shoulder 60 are changed to positions where the upward reaction force and the downward elastic force due to such a change in the height of the workpieces 2 are balanced. The first elastic member 51 is set so that the insertion amount of the stirring pin 50 and the shoulder 60 at this time is approximately the same as the insertion amount when the height of the workpiece 2 has no error from the set value. If the elastic force of the first elastic member 51 is too weak, the upward reaction force caused by the change in the height of the workpiece 2 becomes larger, and the insertion amount becomes smaller. On the other hand, if the elastic force of the first elastic member 51 is too strong, the downward elastic force caused by the change in the height of the workpiece 2 becomes larger, and the insertion amount becomes larger. That is, even if the height of the workpiece 2 fluctuates and becomes higher, the first elastic member 51 is set so that the stirring pin 50 is inserted into the workpiece 2 at a desired depth set according to the set value height of the workpiece 2 in the rotating tool 1. Also, even if the height of the workpiece 2 fluctuates and becomes higher, the first elastic member 51 is set so that the shoulder 60 is in contact with the workpiece 2 and the first elastic member 51 is not inserted into the workpiece 2 and presses the workpiece 2.

[0042] Furthermore, when the height of the workpieces 2 becomes lower than the set value, as shown on the right side of Fig. 4, the first elastic member 51 expands and the assembly 70 including the stirring pin 50 moves down. In this way, even if the height of the workpieces 2 fluctuates and becomes lower, the first elastic member 51 is set in the rotary tool 1 so that the stirring pin 50 is inserted into the workpieces 2 at a desired depth set according to the set height of the workpieces 2. Also, even if the height of the workpieces 2 fluctuates and becomes lower, the first elastic member 51 is set in the rotary tool 1 so that the shoulder 60 is in contact with the workpieces 2 and the first elastic member 51 presses down the workpieces 2 without being inserted into the workpieces 2.

[0043] Thereafter, at the stirring pin withdrawal position, as the rotating tool 1 is moved away from the workpieces 2, first the shoulder 60 separates from the workpieces 2. As the rotating tool 1 is moved further away from the workpieces 2, the insertion amount of the stirring pin 60 gradually decreases. Then, as the rotating tool 1 is moved even further away from the workpieces 2, the stirring pin 60 separates from the workpieces 2.

[0044] As described above, in the rotating tool 1, the stirring pin 50 is inserted into the workpieces 2 at a constant depth by the action of the first elastic member 51, so that a plasticized region is formed at a constant depth. Therefore, stable joining quality can be obtained. Also, in the rotating tool 1, the stirring pin 50 is inserted into the workpieces 2 to perform friction stirring while the shoulder 60 is kept pressing the workpieces 2 by the action of the second elastic member 51, so that the shoulder 60 can hold down the metal material that overflows from the insertion portion of the stirring pin 50 due to friction stirring by the stirring pin 50. Therefore, the occurrence of burrs can be reduced.

[0045] [4. Actions and Effects] According to the rotary tool 1, the welding device 3, and the welding method of the present embodiment, the assembly 70, which is provided movably in the axial direction of the rotary shaft 12, is biased toward the tip side by the first elastic member 51, so that when the tip portion 52 of the stirring pin 50 is inserted into the workpiece 2, the stirring pin 50 is inserted to a predetermined depth in accordance with the elasticity of the first elastic member 51. Also, since the assembly 70 is biased toward the tip side by the first elastic member 51, the shoulder 60 is pressed against the workpiece 2 in accordance with the elasticity of the first elastic member 51. By setting the first elastic member 51 in consideration of welding conditions such as the joining material and the joining mode, the stirring pin 50 can be inserted to a desired depth and the workpiece 2 can be pressed down by the shoulder 60. In other words, the rotary tool 1 can perform pseudo load control using the first elastic member 51.

[0046] When a rotary tool without an elastic member is attached to a joining device such as a machining center that can only perform position control, the support height of the rotary tool 1 is constant based on the setting value of the machining center, and the insertion position of the stirring pin 50 is approximately constant. In contrast, when the rotary tool 1 of this embodiment is used, even if the support height of the rotary tool 1 by the machining center is constant, the first elastic member 51 expands and contracts appropriately in response to fluctuations in the height of the workpieces 2, and the assembly 70 moves in the axial direction. In this way, by utilizing the elasticity of the first elastic member 51, it is possible to control the load, which allows the insertion depth of the stirring pin 50 into the workpieces 2 and the contact state of the shoulder 60 with the workpieces 2 to be controlled.

[0047] The rotating tool 1 is provided with a shoulder 60 that is arranged to be movable separately from the stirring pin 50 in the axial direction of the rotating shaft 12 without receiving a rotational force from the rotating shaft 12 and presses the workpieces 2. The shoulder 60 presses down the metal material that overflows from the insertion portion of the stirring pin 50 due to friction stirring by the stirring pin 50, thereby reducing the occurrence of burrs. In this way, the shoulder 60 improves the finish of the surface after friction stir welding.

[0048] The main body 10 further includes a cylindrical holder 21 and a slide shaft 31 that is accommodated in the center of the holder 21 so as to be slidable in the rotation axis direction and rotates synchronously with the holder 21, and the assembly 70 is provided at the tip of the slide shaft 31. This allows the assembly 70 to slide in the rotation axis direction while transmitting a rotational force from the main body 10 to the assembly 70.

[0049] The first elastic member 51 is disposed so as to surround the lower portion of the slide shaft 31. As a result, the first elastic member 51 is positioned near the middle portion between the slide shaft 31 and the stirring pin 50, and the first elastic member 51 acts evenly in the circumferential direction of the slide shaft 31. Therefore, even if the slide shaft 31 moves, the first elastic member 51 stably biases the stirring pin 50 toward the tip side. Therefore, the first elastic member 51 can be easily installed, and the accuracy of the load control of the stirring pin 50 can be improved.

[0050] In the rotary tool 1, the first elastic member 51 is housed inside the holder 21 and disposed between the base end of the slide shaft 31 and the fixed portion side of the holder 21. This allows the first elastic member 51 to be located near the middle portion between the slide shaft 31 and the stirring pin 50, and allows the force that the first elastic member 51 receives from the stirring pin 50 side to be received by the holder 21. Therefore, even if the slide shaft 31 moves, the first elastic member 51 stably biases the stirring pin 50 toward the tip side, thereby improving the accuracy of the load control of the stirring pin 50.

[0051] In addition, a key groove 23 is formed in the holder 21, and a key 32 is formed in the slide shaft 31. This allows the slide shaft 31 and the assembly 70 to rotate synchronously with the rotation of the holder 21, while allowing stable movement in the axial direction. This makes the operation of the stirring pin 50 and the shoulder 60 even more stable.

[0052] A bearing 63 is interposed between the shoulder 60 and the stirring pin 50. Therefore, the shoulder 60 and the stirring pin 50 can rotate relatively in a stable state.

[0053] In addition, since the rotating tool 1 is equipped with a holding portion 80 that holds the shoulder 60 in a non-rotating state, it becomes easier to hold the shoulder 60 in a non-rotating state, and the finish of the surfaces of the workpieces 2 after friction stir welding is improved.

[0054] In the rotary tool 1, the first elastic member 51 is an elastic member that imparts elastic force by at least one selected from a solid spring, a fluid spring, a magnetic force, and an electromagnetic force. With such a configuration, the elasticity of the first elastic member 51 can be easily adjusted.

[0055] The welding apparatus 3 includes a rotary tool 1, a power means, and a position control means. The rotary tool 1 is moved by the position control means to a predetermined height position relative to the workpieces 2, and the stirring pin 50 is inserted into the workpieces 2 while pressing the shoulder 60 against the workpieces 2, thereby performing friction stir welding on the workpieces 2. According to the welding apparatus 3, by utilizing the elasticity of the first elastic member 51, friction stir welding can be performed while performing load control that controls the insertion depth of the stirring pin 50 into the workpieces 2 and the contact of the shoulder 60 with the workpieces 2. In addition, the shoulder 60 presses down the metal material that overflows from the insertion portion of the stirring pin 50 due to friction stirring by the stirring pin 50, thereby reducing the occurrence of burrs, and the surface finish after friction stir welding is improved. Therefore, even if a machining center is used, pseudo load control is possible, and the surface finish after friction stir welding is improved.

[0056] In this joining method, the rotating tool 1 is moved to a predetermined height position relative to the workpieces 2, and the rotating stirring pin 50 is inserted into the workpieces 2 while pressing the shoulder 60 against the workpieces 2, thereby performing friction stir welding of the workpieces 2. According to this joining method, by utilizing the elasticity of the first elastic member 51, friction stir welding can be performed while controlling the load to control the insertion depth of the stirring pin 50 into the workpieces 2 and the contact of the shoulder 60 with the workpieces 2. In addition, the shoulder 60 presses down the metal material that overflows from the insertion portion of the stirring pin 50 due to friction stirring by the stirring pin 50, thereby reducing the occurrence of burrs and improving the finish of the surface after friction stir welding.

[0057] As described above, according to the rotary tool 1, the welding device 3, and the welding method, it is possible to perform load control even in a state where the rotary tool 1, the welding device 3, and the welding method are mounted on a machining center that performs only position control.

[0058] [5. First Variation] Next, a modified example of the holding part will be described with reference to FIG. 5. In the holding part 85 according to the modified example, as shown in FIG. 5, the shoulder 65 provided below the flange 53 has a rectangular outer shape, and a guide member 86 is provided along the movement trajectory of the rotary tool 1a. The guide members 86 are made of elongated members, and are arranged on both sides of the shoulder 65 with a space of approximately the same length as the width of the second holder so as to sandwich the shoulder 65 from both sides. The guide member 86 is a holding part provided in the joining device 3. The shoulder 65 having such a configuration moves along the movement trajectory without rotating while the outer peripheral surface slides on the side surface of the guide member 86. The stirring pin 50 and the bearing 63 are inserted inside the shoulder 65, similarly to the shoulder 60 in FIG. 1. The other configurations are similar to those of the rotary tool 1 in FIG. 1, so the same reference numerals are used and the description is omitted.

[0059] [6. Second Variation] Next, a modified example of the shoulder will be described with reference to Fig. 6. In the above embodiment, the lower end surface of the shoulder 60 cannot move in the axial direction of the rotating shaft relative to the stirring pin 50, but the shoulder 90 according to the modified example is configured so that the lower end surface of the shoulder can move in the axial direction, as shown in Fig. 6. Specifically, the shoulder 90 includes a first member 91, a second member 92, and a second elastic member 99. The stirring pin 50 and the shoulder 90 are integrated together to form an assembly 75 that moves together in the axial direction of the rotating shaft 12.

[0060] The first member 91 is a portion that is provided so as to be rotatable relative to the stirring pin 50, and is formed of, for example, tool steel. The first member 91 has a cylindrical shape, and is arranged coaxially so as to surround the stirring pin 50. The stirring pin 50 is inserted into a hollow portion 93 of the first member 91. The base end portion (upper end portion in FIG. 5) of the hollow portion 93 has an expanded diameter, and a bearing 63 is inserted between the stirring pin 50 and the first member 91. The bearing 63 is arranged so as to surround the stirring pin 50. This allows the first member 91 to rotate relative to the stirring pin 50, but not to move axially relative thereto.

[0061] A protruding portion 94 is formed at the tip end (lower end in FIG. 6) of the first member 91, protruding from the end face of the first member 91 toward the tip end. The protruding portion 94 has a cylindrical shape, and the stirring pin 50 is inserted inside. The protruding portion 94 is a member for connecting the second member 92. A key 96 is provided at the tip end of the protruding portion 94, protruding outward from the outer circumferential surface. The key 96 is inserted into a key groove 97 of the second member 92, which will be described later. The key 96 has an elliptical shape that is long in the direction of the rotation axis, and is radially arranged at intervals of 180° in the circumferential direction, and is formed in two places. The shape of the key 96 is not limited to an elliptical shape, and may be other shapes such as a circle, an ellipse, an oblong, or a rectangle, as long as it has a width dimension equivalent to that of the key groove 97.

[0062] The second member 92 is a portion that presses the members to be joined while being in contact with the members to be joined. The second member 92 is attached to the protruding portion 94, rotates synchronously with the first member 91, and is a portion that can move relative to the first member 91 in the axial direction of the rotating shaft 12. The second member 92 is formed of, for example, tool steel. The second member 92 has a cylindrical shape and is arranged coaxially so as to surround the stirring pin 50. The stirring pin 50 is inserted into a hollow portion 95 of the second member 92. The base end portion (upper end portion in FIG. 6) of the hollow portion 95 has an expanded diameter, and the tip portion of the protruding portion 94 is inserted into the hollow portion 95. A key groove 97 is formed in the base end portion of the hollow portion 95. The key groove 97 is formed in an elongated oval shape along the axial direction of the rotating shaft 12 (up and down direction in FIG. 6), and is formed in a groove shape on the inner peripheral surface of the hollow portion 95. The key grooves 97 are formed in two positions corresponding to the keys 96 of the protruding portion 94. The axial length of the key groove 97 is longer than the axial length of the key 96, so that the second member 92 can move in the axial direction relative to the first member 91. The width dimension of the key groove 97 is equal to the width dimension of the key 96, so that the second member 92 cannot rotate relative to the first member 91. When the key 96 is located on the base end side of the key groove 97, the tip surface of the second member 92 is flush with the base end of the tapered surface of the tip portion 52 of the stirring pin 50. In other words, the tip portion 52 of the stirring pin 50 protrudes from the tip surface of the second member 92 toward the tip side. When the second member 92 moves from the position toward the first member 91, the axial length of the shoulder 90 becomes shorter.

[0063] The second elastic member 99 is a portion that biases the second member 92, which is a part of the shoulder 90, toward the tip side of the stirring pin 50 in the axial direction of the rotating shaft 12. The second elastic member 99 is configured, for example, as a coil spring, and is disposed so as to surround the outer circumferential surface of the protruding portion 94. It is attached between the tip surface of the first member 91 (the surface to which the base end of the protruding portion 94 is connected) and the base end surface of the second member 92. The second elastic member 99 is configured to bias the second member 92 toward the tip side in response to the force received from the second member 92.

[0064] The elasticity of the second elastic member 99 is set so that when the stirring pin 50 is inserted with a predetermined pressing load into the members to be joined that are made of at least one material selected from the group consisting of aluminum, copper, magnesium, and alloys thereof, the second member 92 is displaced and presses the members to be joined 2 within a predetermined range relative to the total movable range of the second member 92 (the movable length of the key 96 in the key groove 97) by the elastic member. For example, when the second elastic member 99 is a coil spring, and the second elastic member 99 is inserted with a load of 50 kg to 2 t, the second member 92 is set to press the members to be joined in a state in which the deflection amount of the second elastic member 99 is deformed in a range of 0 to 30% relative to the free length of the second elastic member 99. As a result, when the second member 92 is in contact with the members to be joined 2, the second member 92 can easily press the members to be joined 2 without being inserted into the members to be joined 2. The second elastic member 99 is more easily deformed than the first elastic member 51.

[0065] The second elastic member 99 is not limited to a coil spring like the first elastic member 51, and may be a metal spring such as a leaf spring or a disc spring, or a polymeric elastic body (elastomer) such as rubber, polymeric resin, sponge-like resin, etc. Furthermore, the second elastic member 99 may be a fluid spring using air pressure, gas pressure, or hydraulic pressure, or a magnetic spring using magnetic force or electromagnetic force.

[0066] The second elastic member 99 may be set in consideration of the joining conditions so as to satisfy the relationship between the deformation amount and the elastic modulus that allows the shoulder 60 pressed against the workpiece 2 to press down the workpiece 2 without being inserted into the workpiece 2 when in contact with the workpiece 2. Examples of joining conditions that affect the setting of the second elastic member 99 include the conditions of the workpiece 2, such as the material of the workpiece 2 and the shape of the joint, and the joining mode, such as the insertion depth of the stirring pin 50, the shape of the rotating tool 1, the rotation speed, and the movement speed. Note that the shoulder 60 only needs to be in contact with the workpiece 2 at least partially, and some space may be generated between the workpiece 2 and the shoulder 60 depending on the relationship with the surface shape of the workpiece 2, but it is preferable that the shoulder 60 be in contact with the workpiece 2 without any gaps so that the metal material overflowing due to friction stir welding can be pressed down to prevent the generation of burrs. The shoulder 60 may be inserted into the workpiece 2 to some extent, but it is preferable that the shoulder 60 is not inserted deep into the workpiece 2 to such an extent that a recess is not generated due to the contact between the workpiece 2 and the shoulder 70 after welding.

[0067] With this configuration, the tip surface of the shoulder 90 and the stirring pin 50 can move relative to each other, and the load on the shoulder 90 can be controlled by the second elastic member 99. This makes it possible to further improve the accuracy of the load control on the shoulder 90. Furthermore, in the shoulder 90 of this modified example, a holding portion (not shown) may be fixed to the outer circumferential surface of the first member 91, and the holding portion may hold the shoulder 90 and the second member 92 in a non-rotating state.

[0068] [7.Other] Although the embodiment of the present invention has been described above, appropriate design changes are possible within the scope of the present invention. In the above embodiment, the holder 21 is formed with the key groove 23, and the slide shaft 31 is formed with the key 32, but this is not limited to this. The holder 21 may be formed with a key, and the slide shaft 31 may be formed with a key groove.

[0069] In the above embodiment, the rotating tool 1 includes a holding part 80 fixed to the shoulder 60, and the holding part is connected to the welding device to hold the shoulder 60 in a non-rotating state. However, the present invention is not limited to this. The welding device 3 may include a rod-shaped arm member fixed to a fixed system of the welding device 3 as the second holding part, and the second holding part is connected to the shoulder 60 of the rotating tool 1 to hold the shoulder 60 in a non-rotating state. The second holding part is included in the welding device 3. The rotating tool 1 may include a rod-shaped arm member fixed to the shoulder 60 as the holding part 80, and the welding device 3 may include a rod-shaped arm member fixed to a fixed system of the welding device 3 as the second holding part, and the two holding parts are connected to each other to hold the shoulder 60 in a non-rotating state. The holding part is included in the rotating tool 1 and the welding device 3. In this way, the holding part included in the rotating tool 1 and the second holding part included in the welding device 3 and operating in cooperation with the holding part included in the rotating tool 1 may be provided at the same time. As described above, by providing the joining device 3 with the second holding portion that holds the shoulder 60 in a non-rotating state, it becomes easier to hold the shoulder 60 in a non-rotating state, and the finish of the surfaces of the workpieces 2 after friction stir welding is improved.

[0070] In the above embodiment, the first elastic member 51 is disposed so as to surround the lower portion of the slide shaft 31, and is provided between the lower end of the holder 21 and the step portion 54 of the flange portion 53, but is not limited thereto. The first elastic member 51 may be disposed anywhere as long as it is a position that biases the assembly 70 toward the tip side. For example, the first elastic member may be housed inside the holder 21 and attached between the base end portion of the slide shaft and the bottom portion of the holder. In addition, an extension portion that extends in a columnar shape toward the upper end side is formed at the upper end portion of the slide shaft 31, and the first elastic member 51 may be attached between the extension portion of the slide shaft 31 and the fixed portion side of the holder 21 so as to surround the extension portion. In this case, the extension portion may be formed to have a diameter smaller than that of the slide shaft 31 in accordance with the inner diameter of the holder 21. In such a case, the same action and effect as those of the above embodiment can be obtained.

[0071] In the second modified example, the tip 52 of the stirring pin 50 protrudes downward from the bottom surface of the second member 92, but the present invention is not limited to this. The bottom surface of the second member 92 may protrude downward from the tip 52 of the stirring pin 50 when the rotating tool 1 is not in contact with the members to be welded 2. As a result, when the rotating tool 1 is pulled out from the members to be welded 2, the stirring pin 50 is released from the members to be welded 2 before the second member 92, while the second member 92 is pressing the members to be welded 2. At this time, the stirring pin 50 is pulled out while the second member 92 keeps pressing the members to be welded 2, so that the second member 92 can press down the metal material that flows and overflows due to the insertion of the stirring pin 50. Therefore, the hole generated when the stirring pin 50 is pulled out is easily filled with the metal material pressed down by the second member 92. In particular, when friction stir welding is performed at a spot where the rotary tool 1 is inserted and then pulled out without moving it from the inserted position, it becomes easier to prevent the formation of a pullout hole. [Explanation of symbols]

[0072] 1 Rotate Tool 2 Parts to be joined 3 Joining equipment 10 Main body 11 Fixed part 12 Rotation axis 21 Holder 23 Keyway 31 Slide shaft 32 Key 50 Stirring pins 51 First elastic member 60 Shoulder 61 Hollow part 63 Bearing 65 Shoulder 70 Assembly 80,85 Holding part 90 Shoulder 99 Second elastic member

Claims

1. A rotary tool used in a joining apparatus for performing friction stir joining of workpieces, a main body portion having a fixed portion attached to and fixed to the welding device and a rotating shaft for transmitting a rotational force from the welding device; a stirring pin that is disposed in the main body portion so as to be rotatable by receiving a rotational force from the main body portion and so as to be movable in the axial direction of the rotation shaft, and that is inserted into the workpieces to perform friction stirring on the workpieces; and a shoulder that is configured separately from the stirring pin, does not receive a rotational force from the main body, is provided on the main body so as to be movable in the axial direction of the rotation shaft, and presses the workpieces while being in contact with the workpieces; the stirring pin and the shoulder are attached to the main body so as to be relatively rotatable and to move integrally in the axial direction of the rotation shaft, thereby forming an assembly; A first elastic member is provided to bias the assembly toward the tip side of the stirring pin in the axial direction of the rotating shaft. The main body further includes a cylindrical holder attached to the rotating shaft, and a slide shaft that is accommodated in a center of the holder so as to be slidable in the direction of the rotating shaft and rotates synchronously with the holder, The assembly is provided at the tip of the slide shaft, The slide shaft is biased toward the tip side of the assembly via the first elastic member, The first elastic member is accommodated inside the holder and is disposed between a base end of the slide shaft and a fixed portion side of the holder. A rotary tool comprising:

2. The first elastic member is interposed between the assembly and the main body. The rotary tool of claim 1 .

3. A key groove having a long groove shape is formed in the axial direction of the rotation shaft in one of the holder and the slide shaft, and a key is formed in the other of the holder and the slide shaft, the key being provided in a direction intersecting the axial direction of the rotation shaft and fitted into the key groove, The key moves inside the key groove along the axial direction of the rotation shaft as the slide shaft moves in the axial direction of the rotation shaft, As the holder rotates, the key and the key groove come into contact with each other in the circumferential direction, whereby the holder and the slide shaft rotate synchronously. A rotary tool according to claim 1 or 2.

4. A bearing is interposed between the shoulder and the stirring pin. A rotary tool according to any one of claims 1 to 3.

5. The stirring pin further includes a second elastic member that biases the shoulder toward the tip side of the stirring pin in the axial direction of the rotating shaft. A rotary tool according to any one of claims 1 to 4.

6. Further comprising a holding portion for holding the shoulder in a non-rotating state. A rotary tool according to any one of claims 1 to 5.

7. The first elastic member is an elastic member that imparts elastic force by at least one selected from a solid spring, a fluid spring, a magnetic force, and an electromagnetic force. A rotary tool according to any one of the preceding claims.

8. An extension portion is formed at the upper end of the slide shaft, the extension portion extending in a columnar shape toward the upper end side, The first elastic member surrounds the extension portion and is attached between the extension portion and the fixed portion of the holder. The rotary tool of claim 1 .

9. A joining apparatus comprising the rotary tool according to any one of claims 1 to 8, a power unit that outputs a rotational force to be transmitted to the rotation shaft of the rotation tool, and a position control unit that holds the fixed portion of the rotation tool and controls a position of the rotation tool, the position control means moves the rotating tool to a predetermined height position relative to the workpieces, and the stirring pin is inserted into the workpieces while pressing the shoulder against the workpieces, thereby performing friction stir welding on the workpieces. A joining device characterized by:

10. Further comprising a second holding portion for holding the shoulder in a non-rotating state. The joining device according to claim 9.

11. The rotating tool according to any one of claims 1 to 8 is moved to a predetermined height position relative to the workpieces, and the rotating stirring pin is inserted into the workpieces while pressing the shoulder against the workpieces, thereby performing friction stir welding on the workpieces. A bonding method comprising the steps of:

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